Honeywell T874 manual

PRODUCT DATA 60- 2485- 8 ® U.S. Registered Trademark Copyright © 2001 Honeywell • All Rights Reserved T874 Multistage Thermostats and Q674 Subbases APPLICATION These thermostats and subbases provid e low voltage control of multistage heating and c ooling systems, in cluding heat pump systems. FEATURES • T874 Thermostat has si lent, dust-free [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 2 ORDERING INFORMATION When purchasing replacement and modernizat io n products from your TRADELINE® whol esaler or distributor , refe r to the TRADELINE® Catalog or price sheets for complete ordering number . If you have additional questions, need further information, or w oul d like to [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 3 60-2485—8 Standard Models T874 THERMOSTATS Models: See T abl e 3. Electrical Rating: 24 to 30 V ac. Switching: Coiled bimetal elements o perate mercury switches. T empe rature Adjustment: Heating and coo ling setting levers, with separate scales lo cated on top of thermostat base. Common lever for [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 4 Key Lock Cover: Part no. TG504A replaces existing T874 cover . Mounts on T874 base and covers thermostat settling levers and subbase switches. Includes L ED window and two keys. Should not be used with 193121 A Adapter Plate. — TG504A1025: Blank face, int ernal thermometer . — TG504A1[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 5 60-2485—8 Models: See T able 4. Electrical Ratings: Switch Contacts: 2.5A at 30 V ac (7.5A inrush). LED Lights (Optional): 30 V ac. Switches: T wo slide switch es (one switch on Q674G and K; no switches on Q674D) operated by l evers. Switch position is shown on scal eplate. Mounting: Designed to mo[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 6 Optional Speci fications (Q 674 Only): Models available with up to four LEDs; for example, LED s can show EM. HT , AUX. HT , SERVICE, CHECK , FIL TER, and LOCKOUT . See Fig. 3. System switching marked HEA T -OFF/RESET -COOL for sys- tems requiring impedance rela y reset. Available on Q674[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 7 60-2485—8 MERCURY NOTICE This control contains mercury in a sea led tube. Do not place control in the trash at the end of its useful life. If this control is replaci ng a control that contains mercury in a sealed tube, do not place your old control in the trash. Contact your local waste management [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 8 Fig. 5. Instal ling Q674 Subbase on wall. Fig. 6. Subbase compo nents and leveling procedure. Wire Subbase Disconnect power supply before beginning installation to prevent electrical shock or equip ment damage. All wiring must comply with local electrical codes and ordinances. IMPORT ANT [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 9 60-2485—8 Fig. 8. Jumper adjacent ter minals for special sys tem hookup usin g stripped wire 3/4 in. (19 mm). For nonadjacent termina ls and using jumper wire supp lied with subbase. T able 5. T erminal Designations a St andard T erminal Designation Alternat e Designations or Customer Specials T yp[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 10 Outdoor Disconnect The National Electrical Code require s the installation of a disconnect switch w ithin sight of the outdoor unit of an air conditioner or hea t pump. The swit ch is for the safety of any technician working on the unit. The technician can assure that the unit remains un[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 60-24 85—8 8. Move the HEA T and COOL levers to the maximum tem- perature desired. 9. Slide the stop brackets until on e rests against the HEA T lever and the other against the COOL le ver . 10. Firmly tighten the mounting screw . 11 . If th e HEA T and COOL levers are to be locked in place at a [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 12 Most heat pump systems should cycle 2-1/2 to 3 times per hour . 4. Hang the upper edge of the thermostat cover on top o f the thermostat base and swing the cover downward until it engages with the cover clip. Fig. 1 1. Adjustable heat anticipator scales. Temperature Setting Move the heat[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 13 60-2485—8 smaller differential. In cooling, slide the lever closer togethe r for a larger differential, or wider apart for a smaller differential. While supporting the scale with hand, tighten the tension screw . IMPORT ANT Support the scale with ha nd while tightening tension screw . See Fig. 13.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 14 Move the system switch on the Q674 Subbase to COOL or AUTO. Move the cool setting lever on the T874 Multistage Thermostat about 10°F (6°C) below room temperature. See Fig. 12. The cooling eq uipment and fan should start. If the system has two stages of cooling, both stages should start[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 15 60-2485—8 thermostats. The schematics can be field-modified as required (EX: if T874C is being used, eliminate se cond stage of heat). For heat pump circuits: Cool changeover valve—operates on cooling. The revers- ing valve or relay is activa ted either by moving the sys- tem switch to COOL (man[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 16 Fig. 17. Internal schematic an d typical hookup of a T874R Thermo stat and Q674L Subbase in a heat pump application. The thermostat provides two-stage heating and one-stage cooling manual changeover operate s on cooling. M5072A (HOT) L1 L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 17 60-2485—8 Fig. 18. T racing the chang eover relay circuit. Fig. 19. T racing the heat 1 and anticipation circuit. M584 0 L1 (HOT) L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR CHANGEOVER VALVE EM. HT. RELAY RTD 1 AUX.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 18 Fig. 20. T racing the heat 1 anticipation circuit. Fig. 21. T racing the heat 2, anti cipation and AUX. HT . LED circuit. M5842 L1 (HOT) L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR CHANGEOVER VALVE EM. HT.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 19 60-2485—8 Fig. 22. T racing the eme rgency heat and EM. HT . LED circuit. Fig. 23. T racing the cooling circui t. M5844 L1 (HOT ) L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR CHANGEOVER VALVE EM. HT. RELAY RTD 1 AUX.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 20 Fig. 24. T racing the auto fan circuit. Fig. 25. Tracing the fan on circui t. M5846 L1 (HOT ) L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR CHANGEOVER VALVE EM. HT. RELAY RTD 1 AUX. HT. LED (GREEN) EM. HT. L[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 21 60-2485—8 OPERATION Heat Anticipation/Cool Anticipation When controlling a heating uni t with a thermostat, the temperature does not remain exactly at the thermostat setpoint, but varies within a certain temperature range. Heat anticipation is added to the thermostat to reduce this range. The anti[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 22 CAUTION Equipment Damage Hazard . Due to calibration techniques used for T874 Thermostats with outdoor reset, the C815A Thermistor must be wired into the system at all times. Failu re to do so will result in serious degradation of performance. Service and Replacement of C815A Outdoor The[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 23 60-2485—8 Fig. 31. System switching for automatic changeover . Automatic changeover is frequentl y used in areas where ther e are large temperature differences in 24 hours. Some uses for the automatic changeover feature are in the southern states (cool in the morning and hot in the a fternoon) and[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 24 one controlling the auxiliary heat) makes on ly when the heat pump alone cannot handle the load . That is h ow the strategy of using the most economical heat first is imp lemented. Cycling Rate Normally , thermostat anticipation is set to cycle a fossil fuel furnace about five or six tim[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 25 60-2485—8 Low Temperature Lockouts Some manufacturers of heat pumps have previously controlled their units so the compressor was locked out below a specified outdoor temperature. This was done because of the stress placed on the compressor by the very cold temperatures, and the fact that efficienc[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 26 Defrost Control In some regions, during half or mo re of the heating season, the outdoor coil operates b elow 32°F (0°C) Fro st or ice build s up on the outdoor coil of a heat pump similarly to the frost buildup in a h ousehold refrigerator . Eventually , this accumulation of ice inter[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 27 60-2485—8 Fig. 39. Auxiliary heat in two-stage thermostat. This method keeps the auxiliary heat off until the heating load is large enough to demand 100 percent heat pump operation. That demand is measur ed by the the rmostat and is the actual heat requirement of the space. The two-stage thermosta[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 28 the thermostat. A set of contacts on the emergency heat relay is used to bypass each out door thermostat so that all electric heat is under immediate thermostat stage-two control. So the emergency heat relay simply bypasses the outdoor thermostats. Se e Fig. 41. In the second method, th [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 29 60-2485—8 CROSS REFERENCE The following section lists the curre nt T874 T rad e replace- ments for T872 and T874 Mul tistage Thermostats. It also lists the Q674 Trade replacements for Q672 and Q674 Subbases. All thermostats listed carry the H oneywell logo unless otherwise noted. When using the Cr[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 30 A1279 General Electric logo; no. A Y28X1 14A; 75°F stop; locking cover; no thermometer . T874A1010 Use T874A1 176 for Dept. of Defense (DoD) application. A1287 General Electric; no . A Y28X09 7A; fan current shunt for auto fan in heating; heat anticipator set at 0.4A. T874A1036/ Q674B10[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 31 60-2485—8 C1 103 Amana logo; anticipator set at 1.2A T 874C1018 C1 1 1 1 Airtemp (Chrysler) logo T874C1018 C1 129 Day and Night lo go; no. 0.1-0.174 T874C10 18 C1 137 Fast cycle performance on both heat stages T874C1018 Adjust anticip ator faster for correct performance . C1 145 Rheem logo T874C10[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 32 C1509 Fedders logo; used with Q672L1 102 Y594R1 425 Wiring differences (old=new): C=X, K=E; remove Y -W1 jumper . C1517 Climatrol logo; used with Q672L1 102 Y594R1425 Wiring d ifferences (old=new): C= X, K=E; remove Y -W1 jumper . C1525 Square D logo; no. HCD-2 T874C1018 C1533 Airtemp lo[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 33 60-2485—8 D1 144 Carrier logo; no. HH07 A T07 2 T874 D1 16 5 D1 151 General Electric logo; no. A Y28X098; 0.4 hea t anticipator setting T874D1 165 D1 169 Airtemp (Chrysler) logo; used with Q672E1 1 18 T874D1 165/ Q674E1049 Wiring differences (old=new): A=W1; set H1 anti cipa tor to 1.2A. D1 177 T [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 34 E1036 American S tandard logo T874E1016 E1044 Y ork logo; locking cove r T874E1016 E1051 ITT logo T874E1016 E1069 Climatrol logo T874E1016 E1077 Airtemp (Chrysler) logo T874E1016 E1085 Lennox logo T874E1016 E1093 T rane logo T874E1016 E1 101 Dunham-Bush logo T874E1016 E1 1 19 Fedders log[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 35 60-2485—8 G1026 Lennox logo; fast cycle performance ; stage 2 heat; fixed anticipator stage 1 heat and cool; changeover with coolin g; us ed with Q672E1019, F1067. None Se e subbase d escription for replacement informa tion. G1034 Westinghouse logo; adjustable anticipator stage 2 heat; fixed antic[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 36 G1208 Marvair logo; special for Crispaire; used with Q672F1 1 66, F1323. Y594G1393 G1216 Janitrol logo ; no. 26G05 ; stage 2 heat anticipator set at 1.2A; used with Q672F1 1 17. Y594G1252 Wiring differences (old=new): C=X. G1224 TRADELINE; adjustable anticipator stage 2 heat; fixed antic[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 37 60-2485—8 N1010 W illiamson logo; a djustable anticipator stage 1 and 2 heat; fixed anticipator stage 1 cool; used with Q672F1 1 33 or F1315. T874N1016/ Q674F1220 N1028 TRADELINE heat mode changeover; used with Q672F1216. T874N1016 N1036 Bard; used with Q672 F1299. T874N1016/ Q674F1220 N1044 T her[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 38 R1 123 Y ork logo; no. 025-21453C; Celsius sca le. Y594R1664 R1 131 Lennox logo; separate auxiliary heat power circuit; fast cycle stage 2 heat anticipator; outdoor reset; used with Q672L1 144, C815A1013. None R1 149 Westinghouse logo; adjustable stage 2 heat anticipator; cooling changeo[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 39 60-2485—8 T able 7 . Q672-Q674 Subbase Cross Reference . Model Number Description Q674 T rade Replacement a Remarks Q672A System: HEA T -AUTO-COOL , Fan: AUTO-ON A1005 S tandard OEM Q674A1019 A1013 TRADELINE Q674 A1019 A1021 RC-RH jumper Q674A 1019 RC-RH jumper required. A1039 RC-RH jumper; Chek L[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 40 B1269 Whalen; Hi-Lo fan switch; con stant fan in heat and cool system switch positions; used with T872C1574. None B1277 Square D no. HCB-5. Q674B1034 B1285 W ards; RC-RH and F-W3 ju mpers; used with T872C1673. Gas Furnace: T874C1018/ Q674B1034 Electric Furnace: T874C1018/ Q674B1075 Adjus[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 41 60-2485—8 E1050 TRADELINE Q674E1049 E1068 RC-RH jumper; used with T872C1 699. Q674E1049 RC-RH jumper required. E1076 RC-RH internal jumper; EM. HT . LED. Q674E1049 R C-RH jumper required. E1084 Carrier no. HH93AZ076; RC-RH jumper . Q674E1049 RC-RH jumper required. E1092 Carrier no. HH93AZ082; RC-R[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 42 F1 125 BDP no. 3442DP90; used with T872G1 1 17, G1 166, G1 174. Y594G1252 Wiring differences (old=new): C=X. F1 133 Williamson; heat pump; EM. HT . LED; heat mode changeover; compressor l ockout in EM. HT .; use d with T872N1010. T874N1016/ Q674F1220 F1 141 Westinghouse; EM. HT . LED; au[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 43 60-2485—8 G1074 Singer no. 02005754; X1 and X2 terminals for field-added indicator lights; used with T872D1375. None G1082 Singer no. 02005792; X1 and X2 terminals for field-added indicator lights; used with T872D1375. None G1090 TRADELINE; B and O terminals. Q674G1070 Q672H System: OFF-ON Fan: NI[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 44 L1052 Ca rrier no. HH93AZ075; heat pump; EM. HT . LED; cool mode chang eover; compressor lockout in EM. HT .; used with T872G1075, G1 182, G1273 , G1307. Y594R1615 Wiring differences (old=new): C=X. L1060 Dunham Bush; EM. HT . LED; used with T872R1099. Y594R1243 L1078 T appan no. B13708-[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 45 60-2485—8 L1342 Le nnox no. 52C7601; used with T872W1 019 and C815A1013. None L1375 Westinghouse; used with T872R127 1, W89. None L1383 Du nham Bush; used with T872R1099. Y5 94R1243 L1391 Willi amson; used with T872R1339. Y594R1243 L1409 Du otherm special; used wi th T872R1321, W 89. None Q672N Sy[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 46 T able 8. T874 Cross R eference. Model Number Fig. No. Description T rade Mode l Replacement Remarks T874A 1-stage heat, 1-stage cool. A1002 44, 65 Honeywel l logo; S tandard OEM; used with Q674B1 331. T874A1036 A1010 44 Honeywell logo; incl udes Allen wrench and screws to lock cover; no[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 47 60-2485—8 A1200 51, 53 Obsolet e . Carrier logo; part no. HH07A T164; °C scaleplate; includes Allen wrench and screws to lock cover; used with Q674B. T874A1036 a Set stage 1 heat anticipator for total current draw of fan and stage 1 heat primary; replaceme nt has °F scaleplate. A1226 44 Honeywel[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 48 A1481 44 Obsolete . Hon eywell logo; Carrier part no. HH621602; includes locking cover and non-adjustable range stops set at 72°F (max. heat) and 78°F (min. cool). T874A1036 A1507 44 Obsolete . Cli mate-T el logo; includes Alle n wrench and screws to lock cover and non-adjustable range[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 49 60-2485—8 B1 134 222 Obsolete . Carrier Synergy 2000 lo go; part no. HH07A T1 99; °C scaleplate; used with Q674E1395 (HH93AZ209). T874B1019/ Q674E1049 a Wiring differences (old=new): W1=W; RC-RH jumper required; replaceme nt has no LEDs. T874C 2-stage heat, 1-stage cool. C1000 44, 76 Honeywell lo[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 50 C1216 44 Obsolete . Fa sco part no. 1230-8197. T8 74C1018 C1224 105 Obsolete . Square D logo. T874C1018 C1240 44 Honeywell logo; Honeywell Canada TRADELINE mod el; °C scaleplate; includes Allen wrench and screws to lock cover . T874C1018 Repl acement has °F scaleplate. C1257 44 Obsolet[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 51 60-2485—8 C1489 121 Obsolete . Hon eywell logo; non-adju stable range stops set at 75°F (max. heat and min. cool) (24°C); used with Q674L1 15 7. Y594C1322 a C1497 121 Obsolete . Honeywell logo; meets DoD specifications; used with Q674L1 157. Y594C1322 a C1513 44 Obsolete . Borg-Warner multi-logo[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 52 C1877 53 Obsolete . Hon eywell logo; TRADELIN E model; used with Q674B1554; used in Y594C1421. Y594D1347 Jumper RC-RH; system switch: OFF-HEA T -AUTO- COOL T874D 2-stage heat, 2-stage cool. D1009 166, 82 Obsolete . Hon eywell logo; used wi th Q674F1337, E1007; used in Y594D1222, D1339. T[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 53 60-2485—8 D1215 44 Obsolete . Fri edrich Climate Master logo; part no. A T5415; °F/°C scaleplate. T874D1 165 Replacement has °F scaleplate. D1223 44 Honeywell logo; Honeywell Canada T RADELINE model; Celsius scale. T874D1 165 Replacement has °F scaleplate. D1231 44 Obsolete . Honeywell logo; 1[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 54 D1470 44 Obsolete . Y ork log o; part no. 2TH04701624A; includes Allen wrench and screws to lock cover; °C scaleplate. T874D1 165 Replacement has °F scaleplate. D1488 44 Obsolete . Risco speci al. T874D1 1 65 D1496 44 Obsolete . Borg Warner multi-logo; part no . 6TH04701524A; includes [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 55 60-2485—8 D1801 45, 208 T rol-A-T emp by Honeywell logo; H1 and H2 anticipators set at 0.10A; used wi th Q674B1463, D1 1 15. None Se e T rol-A-T emp for replacement. D1819 44 Marv Air Com St at logo; part no. 50059; adjustable interstage between H1 and H2 and be tween C1 an d C2; includes Allen wr[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 56 D2056 44 Obsolete . ComSt at log o; part no. 50056; °F/°C scaleplate; adjustable interstage on both heating and cooling; includes locking cover and field-adjustable locking levers. T874D1 165 Replacement has °F scaleplate and 2°F fixed differential in heating and cooling. D2064 53 Ob[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 57 60-2485—8 E1081 44 T rane logo; part no. BA Y28X186; °F/° C scaleplate. T874E1016 Replacement has °F scaleplate. E1099 44 Obsolete . Lennox logo; part no. 13F1001; °C sca leplate. T874E1016 Replacement has °F scaleplate. E1 107 44 Honeywell logo; °C scaleplate. T874E1 016 Replacement has °F[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 58 G1014 86, 150 Obsolete . Lennox logo; part no. 24F5801; °F/°C scaleplate; H2 anticipator fa ctory set at 0.25A for fast cycle performance; changeover in cooling mode; independent heating and cooli ng circuits; used with Q674E1 148, F1 1 13. Y594G1252 a Wiring differences (old=new): R=O[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 59 60-2485—8 G1204 162 Honeywell logo; designe d for use on T rane heat pumps; no H2 anticipation; changeover in cooling mode; used with Q674J1043 and C815A1005 ; used in Y594G1 161. Y594G1 161 a Design ed for use on T rane heat pumps. G1212 155 Obsolete . Honeywell logo; H2 antic ipator factory set [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 60 G1444 160 Obsolete . ROCA logo; °C scaleplate; used with Q674J1027. Y594G1567 a Replacement has °F scaleplate. G1451 155 Obsolete . BDP multi-logo; part no. HH641502; used with Q674F1212; used in Y594G1245. T874G1246 a or V594G1252 a G1469 194 Obsolete . No logo; Addison special; used [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 61 60-2485—8 G1659 177 Obsolete . Mammoth logo; 0.8A maximum current through B or O terminal; 12°F differential between H1 and H2 for night setback; us ed with Q674 C1330; used in Y594G1427. Y594H1012 a Wiring differences (old=new): R2=L, R1=none; L-R j umper required; no night setback. T861 1G100 4[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 62 G1873 160 Obsolete . Honeywell logo; TRADELINE model; Premier White® color; designed to replace Y594G10 13 (Y ork part no. 2TH1 1702424), Y594 G1229 (Y ork part no. 6TH1 1 702424), and Y ork part no. 2TH1 1 7704124); used with Q674J1225; used in Y594G1575. Y594G1567 a Replacement is bei[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 63 60-2485—8 H1021 74 Obsolete . Fri edrich Climate Master logo; part no. A T5821 ; °F/°C scaleplate; used with Q674C1041. Y594H1012 a Wiring differences (old=new): Y1=O, Y2=Y ; L-R jumper required; replaceme nt has °F scaleplate. H1039 79 Obsolete . Mammoth logo; °F/°C scaleplate; used with Q67[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 64 J1069 124, 144, 206, 207 Obsolete . Honeywell logo; TRADEL INE model; used with Q674J1282; used in Y594J1019. T851 1G102 1 J1077 124, 171 Obsolete . Nordyne logo; part no. 9148300; °F/°C scaleplate. T851 1G102 1 T874K Heat pump model; 2-stage heat, 1-stage cool, automatic changeover in[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 65 60-2485—8 N1040 179 Obsolete . Hon eywell logo; H1 and C1 antici pation fixed; used with Q674F1261 ; used in Y594N1 015. None N1057 178 Obsolete . Inte rtherm logo; part no. 91 1 1882; used with Q674F1220; used in Y594N1023. T874N1016 N1065 178 Obsolete . Mille r logo; Nordyne part no. 9122240; us[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 66 R1079 123 Obsolete . Ruu d logo; part no. UXMT -C70; used with Q674L1 15 7. Y594R1243 a R1087 120 Obsolete . Hon eywell logo; Special for Dunham Bush; use with Q674L. Y594R1664 a R1095 123 Obsolete . Rheem logo; part no. RXMT -C70; used with Q674L1 15 7. T874R1 152 / Y594R1243 a R1 103 1[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 67 60-2485—8 R1319 191 Obsolete . Carrie r part no. 42QH400083; used with Q674B1281 on two speed fan applications. See OEM for replacement. R1327 120 Obsolete . Borg-Warner multi-logo; part n o. 6TH1 1 702224A; used with Q674L1272; used in Y594R1 193. Y594R1672 a R1335 106 Obsolete . BDP mu lti-logo;[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 68 R1574 132 Obsolete . Comfortmaker logo; part no. 1505739; used with Q674L1538; used in Y594R1383. Y594R1243 a Wiring differences (old=new): C=X, X=L, W=W2. R1582 132 Obsolete . Arcoaire logo; part no. 150739; used with Q674L1538; used in Y594R1391. Y594R1243 a Wiring differences (old=new[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 69 60-2485—8 R1889 120 Honeywell logo; designed to rep lace Y594R1 15 1 (Y ork part no. 2TH1 170232 4), Y594R1 19 3 (Y ork part no. 6TH1 17022 24), and Y ork part no. 2TH1 1 704024; used with Q674L1736 and C815A10 54; used in Y594R1672. Y594R1672 a R1897 230 Honeywell logo; Premier White® color; use[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 70 T874W 3-stage heat, 2-stage cool, manual changeover . W1007 1 18 Obsolete . Honeywell logo; Westinghouse special; used with Q674L1256. T861 1M202 5 (programmable) Includes night setback. W1015 54 Honeywell logo; used with Q674B1216 and C8 15A1005; used in Y594W1014. T874W1015 W1023 233 O[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 71 60-2485—8 T able 9. Q674 Subbase Cross Referen ce. Model Number Fig. No. Description Q674 T rade Replacement Remarks Q674A System: HEA T -AUTO-COOL; Fan: AUTO-ON A1001 71 S tandard OEM. Q674A1019 A1019 71 TRADELINE® model; used with T874A-D. Q674A1019 A10 3 5 71 Obsolete . Trane part no. BAS-0435[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 72 B1240 234 Obsole te . Northrup heat pump; AUX HEA T LED; used with T874 G1 139. Y594G1252 a Wiring differences (old=ne w): Y1=Y2, W1=W2; EM HT system switch position is not operational. B1257 56 Obsolete . LSI-Mammoth; RESET LED; automatic fan operation in heat and cool modes; u sed with[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 73 60-2485—8 B1554 82 Obsolete . TRADELINE; incl udes LOCKOUT LED and removable jumpers b etween RC and RH terminals; used with T874C1877; used in Y594C1421. Y594D1347 Jumper RH-RC; system switch: Off-HEA T -AUTO- COOL. B1562 45 Obsolete . Amana logo; part no. P1217701F; removable jumpers b etween RC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 74 C1207 78 Obsolete . Friedrich; System: OVERRIDE-AUTO-OFF; used with T874P1014. T8600D2028 (programmable) Wiring differences (old=new): L=R, W=O; W-Y jumper required; night setb ack. C1215 97 Obsolete . Friedrich part no. AQ5315; System: OVERRIDE-AUT O-OFF; O VERRIDE and SER VICE LEDs; us[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 75 60-2485—8 C1389 205, 176 Obsolete . Co mm a nd Ai re par t n o. P1099-0021; t w o LEDs; used with T874G-H. None See thermostat description for replacement informa tion. C1397 205, 171 Obsolete . Command Aire part no. P1099-0023; used with T874G-H. None See thermostat description for replacement in[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 76 D1065 63 Obsolete . Includes two LEDs; used with T874F1 122. T874F1015/ Q674D1040 a Replacement has no LEDs. D1099 55, 6 6 Ob solet e . Trane p art no. BAS-0430; used with T874A-F . Q 67 4D 10 40 D1 107 55, 66 Obsol e te . Snyder General part nos. 654958801/ 1520503/ 4ELN30 070. Q674F104[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 77 60-2485—8 E1262 82 Lennox part no. 13F1701. Q674E1049 E1270 198 Obsole te . Carrier p art no. HH93AZ189; u sed with T874L1000 (HH07A T176). Y594G1419 a E-W2 jumper required. E1304 82 Obsolete . BDP part no. P272-1887; used with T874L1026. Y594G1419 a E-W2 jumper required. E1312 224 Obsole te . McQ[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 78 F1089 152 Obsolete . Includes EM HEA T LED; X2-E an d RC-RH jumpers. Q674F1022 F1097 142 Obsolete . Southwest special; W2-X2 jumper . Q674F1 022 F1 105 145 Obsole te . Lennox heat pu mp; EM HEA T LE D; used with T874 G1 154. Y594G1252 a Wiring differences (old=ne w): V=R, Y=W2, F=G , X2=[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 79 60-2485—8 F1360 167 Obsolete . Rheem part no. 41-20797-17; AUX HEA T and EM HEA T LEDs; used with T874G14 93. Y594G1526 a F1378 195 Obsolete . Includes EM HEA T and AUX HEA T LEDs; used with T874G1501. Y594G1252 a Wiring differences (old=ne w): L1=L; changeover in co oling only . F1394 139 Obsolet[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 80 F1675 248 Obsolete . Wa terFurnace logo; part no. T A2 1H03; includes four LEDs. See OEM for replacement. Q674G System: OFF-AUTO; Fan: None G1005 184 Obsolete . Used in Y594F1063. Q674G1070 G1013 186 Obsolete . Clima te Control; used with T874D1 298. See OEM for replacement. G1021 91 Obs[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 81 60-2485—8 J1084 171 Obsolete . BDP heat pump; part no. 34427DP126, P272-1879; EM HEA T LED; used with T874J1010. Y594J1019 Wiring differences (old=new): W1=W2, F=L. J 111 8 1 9 6 O b s o l e t e . Carrier heat pump; p art no. HH93AZ188; SUPL HEA T LED; System: SU PL.HT .-ON-OFF; used with T874G10 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 82 K1026 95 System: OFF-WOOD-WOOD/ OIL-OIL ; used with T874F1 155. Q674K1026 K1034 93 Obsolete . Snyder Genera l part no. 4ELN-7920. Q 674E1049 Fan switch is not operational. K1042 93 Obsolete . Carrier part no. HH93AZ172-W; gray color ; includes removable ju mper between RC a nd RH termina[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 83 60-2485—8 L1 199 1 14 O bsolete . Lennox no. 24F 6001; used with T874D1207 and C815A1013. T861 1M2025 (programmable) Wiring differences (old=new): V -VR=R, Y=W3, X=C, R=O, M=Y , M2=Y2-W2, F=G; jumper Y2-W2; no outdoor reset needed; use only one system transformer . L1207 1 15 Used with T874R1 1 52[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 84 L1405 106 Obsole te . BDP heat pump; part no. HH641501; used with T874R1335; use d in Y594R1201. Y594R1243 a L1413 133 Obsole te . Fedders he at pump; used with T874R1343; used in Y594R1219. Y594R1425 a Wiring d ifferences (old=new): K=E, C=X, Z=L; remove W1-Y jumper . L1421 125 Obsole t[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 85 60-2485—8 L1678 209 Trol-A-T emp by Honeywell; gray color; use d with T874R1707; used in Y594R1490. None See T rol-A-T emp. L1686 209 Trol-A-T emp by Honeywell; used with T874R1715; used in Y594R1508. None See T rol-A-T emp. L1702 132 Obsole te . Snyder General heat pump; part no. 654958B07; used [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 86 L1868 125 TRADELINE; in cludes two LEDs; used with T874R1988; used in Y594R179 7; direct replacement for Evcon/Coleman Y594R1 235 (T874R1368/ Q674L1421) Coleman part no. 3600-368. Y594R1797 a L1876 245 Obsole te . Amana part no. 10573902; includes two LEDs; used with T874R2002; use d in [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 87 60-2485—8 T ab le 10. Y594 C ross Referenc e. Model Number Fig. No. Description Tr a d e M o d e l Replacement a Remarks Y594A A1001 46 Obsole te . Amana part no. D68535-1 1; contains T874A1077 , Q674B1075. T874A1036/ Q674B1075 A1019 82 Obsole te . Amana part no. P68535-12; contains T874A1077, Q6 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 88 C1348 70 Obsolete . Fiberglas; contains T874C1653, Q674S1000. T874C1000/ Q674B1075 Wiring differences (old=new): Y=Y1; jumper RC-RH and Y1- W1; replacement has no SERVICE LED; replacement has fan switching an d HEA T- OFF-COOL system switching. C1355 45 Obsolete . Nordyne “Miller” pa[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 89 60-2485—8 D1347 82 TRADELINE® contains T874D1942, Q674E1403. Y594D1347 D1354 82 SUPER TRAD ELINE® contains T874D2031 (no cover), Q674E1049, a nd TG504A with two keys. Y594D1354 D1370 45 Obsolete . Carrier part no. 50QE90022101; contains T874D2049 and Q674B1539. T874D1 165/ Q674B1034 Replacement [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 90 G1294 79 Obsolete . LSI; contains T874G1378 , Q674C1 124. See OEM for replacement. H2 is night setback. G1328 194 Obsolete . Addison part no. 8403-197; contains T874G1543, Q674F1 345. Y594G1252 Wiring differences (old=ne w): Y1=O, X=L, C=X. G1344 194 Obsolete . Heat Controller part no. 7[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 91 60-2485—8 G1617 73 Obsolete . Carrier part no. 50QE900201 01; contains T874G1949 and Q674C15 04. Y594H1012 a Wiring d ifferences (old=new): Y1=O, Y2=Y , L=R, R=none; R-L jumper required; no night setback. T8600D2028 (programmable) Wiring differences (old=new): Y1=O, Y2=Y , L=R; W-Y jumper required[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 92 J1019 244 Obsolete . TRADELINE; automatic changeove r; contains T874J1069 and Q674J1282 ; direct replacement for T87 4J1002 or T874J1028 used with Q674J1068 or Q674J1 159 (HH07A T175 or HH07A T165 used with HH 93AZ183 or HH93AZ196). (Recontrol) T851 1G1021 Y594N N1007 178 Obsolete . Will[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 93 60-2485—8 R1292 108 Contains T874R1467 and Q674L1512 ; replaces Y594R1 1 10 (T874R1 137/Q674L1 132). Y594R1292 R1300 123 Contains T874R1475 and Q674L1520 . Y594R1300 R1318 130 Obsolete . Comfortmaker part no. 1505721; contains T874R1483, Q674L153 8 and C815A1005. Y594R1763 Wiring differences (old=[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 94 R1615 230 TRADELINE; contains T874R1822 and Q674L1710; replaces Y594R1326 (T874R14 91/ Q674L1553). Y594R1615 R1623 134 Obsolete . Rheem U niversal Parts part no. 41- 20796-46; contains T874R1558 an d Q674L1504. Y594R1300 R1631 134 Rheem part no. 41-20796-29; contains T874R1442 and Q674L1[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 95 60-2485—8 R1797 125 TRADELINE; contains T874R1988 and Q674L1868; direct replacement for Y594R1235 (T874R1368/Q674L14 21) Evcon/Coleman part no. 3600-368). Y594R1797 a R1805 245 Obsolete . Amana part no. 10636702; contains T874R2002 and Q674L187 6. Y594R1797 Wiring differences (old=ne w): C/X=X. R1[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 96 WIRING DIAGRAMS Fig. 44. Schema tic and hookup of T874A, B,C,D,E,F with Q674B. Used in standard applications. Fig. 45. Schematic and h ookup of T874C,D wi th Q674B. Use d in standard applications. H1 FALL L1 (HO T) L2 1 RH W1 W2 O G Y2 Y1 RC HEAT RELAY 2 HEAT RELAY 1 HEAT OFF COOL SYSTEM[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 97 60-2485—8 Fig. 46. Schematic and h ookup of T874A,B,D with Q674B. Use d in standard applications. . Fig. 47. Schematic an d hookup of T874R wi t h Q674B. Used in heat pump applications. H1 FALL W1 W2 O G Y2 Y1 HEAT RELAY 2 HEAT RELAY 1 HEAT OFF COOL SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 98 Fig. 48. Schematic and hookup of T874D with Q674B. Used in standard applications. H1 FALL W1 G W2 B RH X1 O FAN RELAY HEAT RELAY 1 HEAT OFF COOL SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITCH 2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 99 60-2485—8 Fig. 49. Schematic a nd hookup of T874C with Q674B. Used in st an dard applications. Fig. 50. Schematic and hookup of T874G with Q674B. Used in heat pump applications. L1 (HOT ) L2 1 H1 FALL H2 FALL C1 RISE L1 (HOT ) L2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 100 Fig. 51. Schematic and hookup of T874D with Q674B. Used in standard applications. Fig. 52. Schematic and hookup of T874C with Q674B. Used in standard applications. C2 RISE L1 (HOT) L2 1 L1 (HOT) L2 1 3 3 C1 RISE H2 FALL H1 FALL M594 4 H1 ANTICIPATOR H2 ANTICIPATOR C1 ANTICIPATOR C2 ANTI[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 101 60-2485—8 Fig. 53. Schematic a nd hookup of T874D with Q674B. Used in st an dard applications. Fig. 54. Schemati c and hookup of T874 W wi th Q674B. Us ed in st andard ap plications. H1 FALL W1 W2 G Y2 Y1 HEAT RELAY 2 HEAT RELAY 1 H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITCH 1 POWER SUPPLY. P[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 102 Fig. 55. Schematic an d hookup of T874 A,D,F with Q674D. Used in standard ap plications. Fig. 56. Schematic and hookup of T874C with Q674B. Used in standard applications. M3667A POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. JUMPER RC, RH FOR SINGLE TRANSFOR[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 103 60-2485—8 Fig. 57. Schematic and hookup of T874P with Q6 74B. Used in heat pump applications . Fig. 58. Sc hematic and hookup of T 874G with Q674D. Used in st an dard applications. H2 FALL H1 RISE CO L1 (HOT ) L2 1 C1 RISE 2 1 2 POWERSUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQ[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 104 Fig. 59. Sche matic and hookup of T874 A wi th Q674Q. Used in fan coil applicatio ns. Fig. 60. Schematic and hookup of T874C with Q67 4 N. Used in evapora tive cooler applica tions. L1 (HOT) L2 1 K2 RELAY SYSTEM SWITCH ON HIGH H1 ANTICIPATOR H1 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT ME[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 105 60-2485—8 Fig. 61. Schematic and hookup of T874C with Q6 74N. Used in evaporative c ooler applicatio ns. Fig. 62. Schematic and hookup of T874F wi th Q674B. Used in wood/coal applicatio ns. L1 (HOT ) L2 EVAPORATOR RELAY ELEC. HT. RELAY FAN RELAY COMPRESSOR CONTACTOR CHANGEOVER RELAY O Y2 W2 G R H[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 106 Fig. 63. Schematic and hookup of T874F with Q674D. Used in wood/coal applications. Fig. 64. Sche matic and hookup of T874 A wi th Q674Q. Used in fan coil applicatio ns. L1 (HO T) L2 1 NO SYSTEM SWITCH H2 ANTICIPATOR H1 H2 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTEC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 107 60-2485—8 Fig. 65. Schematic a nd hookup of T874A with Q674B. Used in st an dard applications. Fig. 66. Schematic and hook up of T874A,D,F with Q674D. Used in standard applications. C1 RISE L1 (HOT ) L2 1 L1 (HOT) L2 1 H1 FALL POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQU[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 108 Fig. 67. Schematic an d hookup of T874 R wit h Q674B. Used in heat pump applications. Fig. 68. Schematic and hook up of T874P with Q674B. Used in heat pump application s. M5998 H2 FALL H1 FALL C1 L1 (HOT) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 109 60-2485—8 Fig. 69. Schematic and hookup of T874V wi th Q674R. Used in fan co il applications. Fig. 70. Schematic and hook up of T874C with Q674S. Used in heat pump applications. C1 RISE L1 (HOT) L2 1 M107 A FAN SWITCH LO AUTO HI CONT. SYSTEM SWITCH OFF COOL C1 ANTICIPATOR POWER SUPPLY. PROVIDE DI[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 1 10 Fig. 71. Schematic and hookup of T874A-D with Q674A. Use d in standard applications. Fig. 72. Schematic and hook up of T874D,E,F with Q674C. Used in standard applications. H1 FALL L1 (HOT ) L2 1 RH W1 W2 G Y2 Y1 RC HEAT RELAY 2 HEAT RELAY 1 HEAT AUTO COOL SYSTEM SWITCH H1 ANTICIPATOR C[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 1 60-24 85—8 Fig. 73. Schematic and hookup of T874G with Q674C. Used in heat pump applications. Fig. 74. Schematic an d hookup of T874H wi t h Q674C. Used in heat pump applications. H1 FALL G Y1 R FAN RELAY REVERSING VALVE RELAY OFF AUTO SYSTEM SWITCH H ANTICIPATOR C ANTICIPATOR AUTO ON FAN SWITC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 1 12 Fig. 75. Schematic and hookup of T874A with Q674C. Used in standard applications. Fig. 76. Schematic and hookup of T874A-D with Q674C. Use d in standard applications. C1 RISE L1 (HO T) L2 1 3 H1 FALL 2 THERMOSTAT SUBBASE SYSTEM COMPONENTS SYSTEM SWITCH OFF AUTO FAN SWITCH AUTO ON HEAT [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 3 60-2485—8 Fig. 77. Schematic an d hookup of T874K wi t h Q674C. Used in heat pump applications. Fig. 78. Schematic and hookup of T874P with Q6 74C. Used in heat pump applications . C1 RISE H1 H2 CO FALL FALL FALL L1 (HOT) L2 1 1 2 L1 (HOT) L2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 1 14 Fig. 79. Schematic and hookup of T874G ,H wi th Q674C. Used in standard applications. Fig. 80. Schematic and hookup of T874D with Q674E. Use d in standard applications. O 1 THERMOSTAT SUBBASE SYSTEM COMPONENTS R1 G R2 H1 ANTICIPATOR CO RISE H1 FALL FALL H2 C1 C1 ANTICIPATOR POWER SUPPL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 5 60-2485—8 Fig. 81. Schematic an d hookup of T874C wi t h Q674C. Used in heat pump applications. Fig. 82. Schematic and hookup of T874 A,C,D wi th Q674E. Us ed in st andard ap plications. H1 FALL L1 (HOT) L2 1 H2 ANTICIPATOR OFF AUTO FAN SWITCH CHANGEOVE R RELAY M5981 POWER SUPPLY. PROVIDE DISCO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 1 16 Fig. 83. Sche matic and hookup of T 874G with Q674 C. Used in standard applications. Fig. 84. Schematic and hookup of T874 G with Q674E. Used in heat pump applications. H1 FAN SWITCH ON AUTO CHECK LED (RED) M5982 POWER SUPPLY. PROVIDE DISCONECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 7 60-2485—8 Fig. 85. Schematic and hookup of T874A-D wi th Q674E. Use d in standard applications. Fig. 86. Schematic and hookup of T874 G with Q674E. Used in heat pump applications. H1 FALL 4 H1 ANTICIPATOR W2 HEAT RELAY 2 L1 (HOT) L2 1 COMPRESSOR CONTACTOR 1 M5983 POWER SUPPLY. PROVIDE DISCONECT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 1 18 Fig. 87. Schematic and hookup of T874D with Q674E. Use d in standard applications. Fig. 88. Schematic and hookup of T874B,D with Q674E. Use d in st andard applicatio ns. C2 RISE C1 RISE H2 FALL H1 FALL L1 (HOT) L2 1 L1 (HOT) L2 1 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOA[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 1 1 9 60-2485—8 Fig. 89. Schematic and hookup of T874D with Q674E. Use d in standard applications. Fig. 90. Schema tic and hookup of T874D with Q674 G . Used in st andard ap plications. Y1 W1 RC 1 M7023 THERMOSTAT SUBBASE SYSTEM COMPONENTS B Y2 G W2 RH X H1 ANTICIPATOR H2 ANTICIPATOR C1 RISE H1 FALL [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 120 Fig. 91. Schematic an d hookup of T874 A-F ,Q with Q674G . Used in standard applications. Fig. 92. Schematic an d hookup of T874 C with Q674G . Used in heat pu mp applications. H1 FALL L1 (HOT ) L2 1 RH W1 W2 O Y2 Y1 RC HEAT RELAY 2 HEAT RELAY 1 OFF AUTO SYSTEM SWITCH H1 ANTICIPATOR C1 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 121 60-2485—8 Fig. 93. Schematic a nd hookup of T874D with Q674K. Used in st an dard applications. Fig. 94. Schema tic and hookup of T874D with Q674 G . Used in st andar d applications. H1 FALL H2 FALL C1 RISE C2 RISE L1 (HOT) L2 L1 (HOT) L2 1 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD P[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 122 Fig. 95. Sche matic and hookup of T874F with Q674K. Used in wood/oil applicatio ns. Fig. 96. Schematic and hookup of T874C with Q674C. Used in standard applications. H1 FALL 1 OFF WOOD SYSTEM SWITCH H1 ANTICIPATOR WOOD/OIL OIL OIL LED (RED) W2 M5984 POWER SUPPLY. PROVIDE DISCONECT MEANS[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 123 60-2485—8 Fig. 97. Schematic and hookup of T874P with Q6 74C. Used in heat pump applications . Fig. 98. Schematic and hookup of T874D with Q674E. Use d in standard applications. H2 FALL H1 RISE CO L1 (HOT) L2 1 C1 RISE COMPRESSOR CONTACTOR FAN RELAY CLOSED-DAY OPEN-NITE B RELAY SERVICE LED (RED) [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 124 Fig. 99. Schematic and hookup of T874C with Q674C. Used in standard applications. L2 1 ON H1 ANTICIPATOR H2 ANTICIPATOR H1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. MOMENTARY POSITION. SPRING RETURN TO "ON" UPON SWITCH RELEASE. H1 AND C1 ARE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 125 60-2485—8 Fig. 100. Schematic and hookup of T874W with Q674C. Used in standard applications. Fig. 101. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . L2 1 ON H1 ANTICIPATOR H2 ANTICIPATOR H1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 126 Fig. 102. Schematic and hookup of T874J,R with Q674L. Used in heat pump applications. H2 FALL H1 FALL C1 L1 (HOT) L2 1 L1 (HOT) L2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FIELD WIRE JUMPER TO ALLOW SINGLE SYSTEM TRANSFORMER. 1 2 THERMOSTAT SUBBASE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 127 60-2485—8 Fig. 103. Schematic and hookup of T874G with Q6 74L. Used in heat pump application s. Fig. 104. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H2 ANTICIPATOR 1 SUPL. HT. LED (RED) M466 5 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQU[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 128 Fig. 105. Schematic and hookup of T874C with Q67 4L. Used in heat pump app lications. Fig. 106. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. OFF COOL IHRI RHI FAN SWITCH ON SYSTEM SWITCH SYSTEM MONITOR SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OV[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 129 60-2485—8 Fig. 107. Schematic and hookup of T874 D wit h Q674L. Used in heat pump applications . Fig. 108. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . C2 RISE C1 RISE H2 FALL H1 FALL L1 (HOT) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 130 Fig. 109. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H2 FALL L1 (HOT) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. THERMOSTAT SUBBASE SYSTEM COMPONENTS H1 FALL C1 H1/ C1 ANTICIPATOR SYSTEM SWITCH FAN SWITCH AUTO ON O[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 131 60-2485—8 Fig. 1 10. Sch ematic and hookup of T87C,R with Q674L. Used in heat pump a pplications . L1 (HOT) L2 1 F EM. HT. LED (YELLOW) R SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M2854 VR H1 FALL E AUTO ON FAN[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 132 Fig. 1 1 1. Schematic a nd hookup of T874R with Q674L. Used in heat pump applications. L1 (HOT) L2 1 COOL HEAT FALL H2 SYSTEM SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M2851 OFF H 1 C1 2 REMOVE FACTORY INSTALLED V-VR JUMPER WHEN CONNECTING A TW[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 133 60-2485—8 Fig. 1 12. Schematic and hook up of T874R with Q674L . Used in heat pump ap plications. OFF COOL COMPRESSOR FAILURE FAN SWITCH ON SYSTEM SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M8383 AUX. HT. RELAY 4 EM. HT. LED (RED) AUX. HT. LED (GREEN) EM.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 134 Fig. 1 13. Schemati c and hookup of T874 R with Q674L. Used in heat pump applica tions. H2 H1 FALL C1 L1 (HOT ) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. THERMOSTAT SUBBASE SYSTEM COMPONENTS H1/C1 ANTICIPATOR FALL H2 ANTICIPATOR SYSTEM SWITCH FAN[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 135 60-2485—8 Fig. 1 14. Schematic and hook up of T874D with Q674L . Used in heat pump ap plications. L1 (HOT) L2 1 F E SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M2 H1 FALL R AUTO ON FAN SWITCH X V M L FAN RELAY H2[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 136 Fig. 1 15. Schemati c and hookup of T874 R with Q674L. Used in heat pump applica tions. M5072A (HOT) L1 L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR COOL CHANGEOVER VALVE EM. HT. RELAY RTD 1 AUX. HT. LED ([...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 137 60-2485—8 Fig. 1 16. Schematic and hook up of T874R with Q674L . Used in heat pump ap plications. H2 FALL H1 FALL C1 YR COM G W O EH O G Y A H W2 R B X E L1 (HOT) L2 1 COMPRESSOR CONTACTOR AUX. HT. RELAY EM. HT. RELAY EM. HT. LED (RED) EM. HT. HEAT OFF COOL COMP. FAULT LED (YELLOW) SYSTEM SWITCH [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 138 Fig. 1 17. Schemati c and hookup of T874 D with Q674L. Used in heat pump applica tions. H1 FALL L1 (HOT) L2 R B 2 3 4 5 6 G Y1 Y2 W X L O ENTHALPY CONTROL RELAY HEAT RELAY CONTACT 1 DEFROST RELAY H1 ANTICIPATOR H2 ANTICIPATOR C1 ANTICIPATOR C2 ANTICIPATOR 2 2 1 1 POWER SUPPLY. PROVIDE D[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 139 60-2485—8 Fig. 1 18. Schematic an d hookup of T87 4W with Q674L. Used in heat pump applications. H1 FALL H2 FALL L1 (HOT) L2 R B 2 1 3 4 5 6 G Y1 Y2 O X E A ECONOMIZER RELAY HEAT RELAY CONTACT 1 DEFROST RELAY H2 ANTICIPATOR H1 ANTICIPATOR H3 ANTICIPATOR C2 ANTICIPATOR C1 ANTICIPATOR RESET HEATER [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 140 Fig. 1 19. Schemati c and hookup of T874 R with Q674L. Used in heat pump applica tions. Fig. 120. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H1 FALL C1 L1 (HOT) L2 1 H2 FALL SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR C1 ANTICIPATOR POWER SUPPLY. [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 141 60-2485—8 Fig. 121. Schematic and hookup of T874 C wit h Q674L. Used in heat pump applications . L1 (HOT) L2 1 R L X W2 G O E B Y ODT1 EHR1 ODT2 EHR2 RTD2 RTD3 RTD1 COMPRESSOR FAILURE HEAT CHANGEOVER VALVE COMPRESSOR CONTACTOR LACO CHP EM. HT. RELAY COOL CHANGEOVER VALVE FAN RELAY RD RTD1 H1 FALL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 142 Fig. 122. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H1 C1 2 3 H2 FALL 5 6 H1/C1 ANTICIPATOR H2 ANTICIPATOR AUTO ON SYSTEM SWITCH EM. HT. HEAT OFF COOL FAN RELAY G R K L 1 C Y W1 SERVICE LED (RED) EM. HT. LED (YELLOW) SERVICE COMPRESSOR CONTACTOR EM. HT.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 143 60-2485—8 Fig. 123. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H2 FALL H1 FALL C1 L1 (HOT) L2 1 2 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. CONNECT CHANGEOVER RELAY TO B FOR HEAT CHANGEOVER, TO O FOR COOL CHANGEOVER. THERMO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 144 Fig. 124. Schematic and hookup of T87 4J with Q674L. Used in h eat pump applications. H1 FALL C1 RISE CO H2 FALL CO RISE L1 (HOT) L2 1 THERMOSTAT SUBBASE SYSTEM COMPONENTS COMPRESSOR CONTACTOR FAN RELAY HEAT RELAY 1 OUTDOOR THERMOSTAT HEAT RELAY CONTACT 1 HEAT RELAY 2 HEAT RELAY CONTACT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 145 60-2485—8 Fig. 125. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . L1 (HOT ) L2 1 X L W2 EM. HT. LED (RED) AUX. HT. LED (GRN) AUX. HT. RELAY FAN RELAY "B" RELAY G COOL CHANGEOVER VALVE EM. HT. RELAY COMPRESSOR CONTACTOR O Y E B SYSTEM SWITCH EM. HT. HEAT OF[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 146 Fig. 126. Schematic and hookup of T874G with Q674P . Used in heat pump applications. Fig. 127. Schematic and hookup of T874C with Q67 4L. Used in heat pump app lications. H2 H1 FALL CO RISE C1 RISE L1 (HO T) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS RE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 147 60-2485—8 Fig. 128. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . Fig. 129. Schematic and hookup of T874G with Q6 74L. Used in heat pump application s. FALL AUTO ON H1 HEAT OFF COOL L2 M5653A POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 148 Fig. 130. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H2 FALL H1 FALL C1 L1 (HOT) L2 1 2 2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FACTORY-INSTALLED JUMPER. THERMOSTAT SUBBASE SYSTEM COMPONENTS H1/C1 ANTICIPATOR H2 AN[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 149 60-2485—8 Fig. 131. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H2 FALL H1 FALL C1 L1 (HOT) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FOR Q674L1454, IS "OFF". THERMOSTAT SUBBASE SYSTEM COMPONENTS H1/C1 ANTICIP[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 150 Fig. 132. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 133. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H2 FALL H1 FALL C1 L1 (HOT) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 151 60-2485—8 Fig. 134. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H2 FALL H1 FALL C1 LACO CHP POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. THERMOSTAT SUBBASE SYSTEM COMPONENTS L1 (HOT) L2 1 H1/C1 ANTICIPATOR H2 ANTICIPATOR SYSTEM SWITC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 152 Fig. 135. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 136. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H2 FALL H1 FALL C1 L1 (HOT) L2 1 R W2 L C G O E Y 2 3 4 6 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 153 60-2485—8 Fig. 137. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H2 FALL H1 FALL C1 LACO CHP POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. THERMOSTAT SUBBASE SYSTEM COMPONENTS L1 (HOT) L2 1 H1/C1 ANTICIPATOR H2 ANTICIPATOR SYSTEM SWITC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 154 Fig. 138. Schematic and hookup of T874L with Q674B . Used in heat pump app lications. Fig. 139. Schematic and ho okup of T874D with Q674F . Used in heat pump applications. M103A R1 NO2 S1 RELAY S1 NC SOLIENOID RELAY FAN RELAY FAN SWITCH AUTO ON J S G R C H2 H1 O AUX. HT. RELAY COMPRESSO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 155 60-2485—8 Fig. 140. Sc hematic and hookup of T874W with Q674L. Used in heat pu mp applications. 1 T W3 U G R E L X B O Y1 Y2 C815A OD THERMISTOR AUX. HT. RELAY FAN RELAY EM. HT. RELAY COMPRESSOR MONITOR HEAT CHANGEOVER RELAY COOL CHANGEOVER RELAY COMPRESSOR CONTACTOR 1 COMPRESSOR CONTACTOR 2 EM.H[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 156 Fig. 141. Schematic and hookup of T874C with Q674F . Use d in st andard applications. Fig. 142. Schematic and hookup of T874 C,D wi th Q674F . Used in st andar d applications. H1 FALL H2 FALL C1 RISE L1 (HOT ) L2 1 H1 ANTICIPATOR 4 1 C2 RISE C1 ANTICIPATOR C2 ANTICIPATOR 8 9 10 POWER SU[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 157 60-2485—8 Fig. 143. Sc hematic and hookup of T874G wit h Q674B. Used in heat pump applications. Fig. 144. Schematic and hookup of T874J with Q674J. Us ed in heat pump applications. THERMOSTAT SUBBASE SYSTEM COMPONENTS M837 8 H1 FALL 1 H1 ANTICIPATOR 2 FAN SWITCH AUTO ON 4 R COMPRESSOR CONTACTOR F[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 158 Fig. 145. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. Fig. 146. Schematic and ho okup of T874D with Q674F . Used in heat pump applications. OFF COOL OUTDOOR THERMOSTAT ON SYSTEM SWITCH FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PR[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 159 60-2485—8 Fig. 147. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. Fig. 148. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. H1 FALL 1 G A X W2 R AUTO COOL SYSTEM SWITCH H1 ANTICIPATOR AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 160 Fig. 149. Schematic and ho okup of T874C with Q674F . Used in heat pump applications. THERMOSTAT SUBBASE SYSTEM COMPONENTS H1 FALL H1 ANTICIPATOR 1 H2 FALL H2 ANTICIPATOR W1 EMR4 2R 1R 5R 3R Y1 G EMR4 EMR2 THERMAL SWITCHES FOR HEATING ELEMENTS HTR 1 C1 RISE HTR 3 HTR 2 OUTDOOR THERMOSTA[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 161 60-2485—8 Fig. 150. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. L1 HOT L2 1 F EM. HEAT LED (RED) V SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M2852A R H1 FALL E AUTO ON FAN SWIT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 162 Fig. 151. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. H1 FALL H2 FALL CO RISE C1 RISE L1 (HOT) L2 1 1 2 1 L1 (HOT) L2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. OPTIONAL FIELD WIRE JUMPER TO CYCLE W2 WITH H1 IN EM. HT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 163 60-2485—8 Fig. 152. Schematic and hookup o f T874D with Q674F . Used in st andar d applications. Fig. 153. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. OFF ON SYSTEM SWITCH FAN SWITCH 1 2 3 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 164 Fig. 154. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. H2 FALL YR COM G W O EH O G Y A H E W2 R 1 COMPRESSOR CONTACTOR EM. HT. HEAT AUTO COOL COMP. FAULT LED (YELLOW) SYSTEM SWITCH FAN SWITCH AUTO ON 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 165 60-2485—8 Fig. 155. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. H2 FALL L1 (HOT) L2 1 R W3 W2 X L G O E Y RTD1 OTD1 EHR1 ODT2 EHR2 RTD2 RTD3 RTD1 SYSTEM MONITOR FAN RELAY RD COOL CHANGEOVER VALVE EM. HT. RELAY LACO COMPRESSOR CONTACTOR CHP 2 3 4 5 6 8 9 10 H1 FAL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 166 Fig. 156. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. Fig. 157. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. COMPRESSOR FAILURE H1 FALL H2 FALL L1 (HOT) L2 1 CO RISE H1 ANTICIPATOR 1 2 4 6 9 8 C1 RISE OFF EM. HT. SYSTE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 167 60-2485—8 Fig. 158. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. 4 OFF EM. HT. SYSTEM SWITCH HEAT AUTO COOL AUX. HT. LED (GREEN) 1 X M5721 8 C1 ANTICIPATOR POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 1 CO RISE FALL H2 6 9 C1 RISE H2[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 168 Fig. 159. Schematic and hookup of T874 G with Q674J. Used in hea t pump applications . Fig. 160. Schematic and hookup of T874 G with Q674J. Used in hea t pump applications . L1 (HOT) L2 1 H1 FALL H1 ANTICIPATOR H2 FALL CO RISE C1 RISE 1 2 4 6 8 9 10 O G R X Y W C1 ANTICIPATOR E OFF AUTO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 169 60-2485—8 Fig. 161. Schematic and hookup of T874G with Q674J . Used in heat pump applicatio ns. H2 ANTICIPATOR 1 SUPL. HT. LED (RED) M572 4 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 1 SYSTEM COMPONENTS SUBBASE THERMOSTAT L1 (HOT ) L2 1 H1 FALL H2 FALL 2 4 6 O G R[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 170 Fig. 162. Schematic and hookup of T874 G with Q674J. Used in hea t pump applications . H1 FALL EM. HT. LED (RED) L1 (HOT) L2 1 AUX. HT. LED (GREEN) F M5725 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 1 SYSTEM COMPONENTS SUBBASE THEROMSTAT B W H2 FALL CO R[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 171 60-2485—8 Fig. 163. Schematic and hookup of T874G with Q674C . Used in standard applications . H1 FALL H2 FALL CO FALL C1 RISE L1 (HOT) L2 1 1 1 1 2 3 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. H2 HAS 10¡F FIXED SETBACK FROM H1 ON T874G1485, 0-12¡F ADJUSTABLE ON[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 172 Fig. 164. Schemati c and hookup of T874H with Q674C. Used in standard applications. Fig. 165. Schematic and hookup of T874L with Q674C . Used in heat pump app lications. H1 FALL L1 (HOT) L2 1 2 OFF FAN SWITCH SYSTEM SWITCH C1 ANTICIPATOR AUTO ON M5726 POWER SUPPLY. PROVIDE DISCONNECT ME[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 173 60-2485—8 Fig. 166. Schematic and hookup o f T874D with Q674F . Used in st andar d applications. H1 FALL L1 (HOT) L2 1 H1 ANTICIPATOR 1 OFF EM. HT. SYSTEM SWITCH FAN SWITCH HEAT AUTO COOL ON AUTO M5728 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 1 SYSTEM COMPONENTS[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 174 Fig. 167. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. M1592A (HOT) L1 L2 1 LACO CHP Y B E G L X W2 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD COMPRESSOR FAILURE FAN RELAY COMPRESSOR CONTACTOR HEAT CHANGEOVER VALVE EM. HT. RELAY RTD 1 AUX. HT. LED ([...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 175 60-2485—8 Fig. 168. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H1 FALL C L1 (HO T) L2 1 EM. HT. LED (RED) AUX. HT. LED (GRN) W3 O L G R W2 E X X2 B W1 Y AUX. HT. RELAY EM. HT. RELAY HEAT CHANGEOVER VALVE W1 RELAY COMPRESSOR RELAY W3 RELAY COOL CHANGEOVER VALVE CO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 176 Fig. 169. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. H1 FALL RISE CO L1 (HOT ) L2 1 3 C1 RISE 1 2 2 3 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. TERMINAL LABELED C/X ON SOME MODELS. W3 TERMINAL ON SOME MODELS ONLY. C1 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 177 60-2485—8 Fig. 170. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. H1 FALL RISE CO L1 (HOT ) L2 1 C1 RISE 1 2 3 3 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. ON SOME MODELS, Y TERMINAL MAY BE LABELED Y1. EMERGENCY HEAT RUNS CONTINUO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 178 Fig. 171. Schematic and hookup of T874J with Q674J. Us ed in heat pump applications. Fig. 172. Sche matic and hookup of T874H with Q674 B. Used in heat pump applications. H1 FALL C1 RISE CO L1 (HOT) L2 1 H1 ANTICIPATOR OFF EM. HT. SYSTEM SWITCH FAN SWITCH AUTO ON AUTO EM. HT. LED (RED) [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 179 60-2485—8 Fig. 173. Sche matic and hookup of T874H with Q674 C. Used in heat pump applications. Fig. 174. Schematic and hookup of T874G with Q674J . Used in heat pump applicatio ns. H1 FALL CO RISE L1 (HOT) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. THERMOS[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 180 Fig. 175. Schematic and hookup of T874 G with Q674J. Used in hea t pump applications . Fig. 176. Schematic and hookup of T874G with Q674C . Used in standard applications . FALL L1 (HOT) L2 1 O G R W2 E L C Y 2 4 6 8 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUI[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 181 60-2485—8 Fig. 177. Schematic and hoo kup of T874G ,H with Q674C. Used in st and ard applications. Fig. 178. Schematic and hoo kup of T874N with Q674F . Used in heat pump applications. H1 FALL L1 (HOT ) L2 1 FALL M114C POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. US[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 182 Fig. 179. Schematic and ho okup of T874N with Q674F . Used in heat pump applications. L1 (HOT) L2 1 W1 W2 EM. HT. LED (RED) CHECK LED (GREEN) FAN RELAY G EM. HT. RELAY COMPRESSOR CONTACTOR Y E SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR H1 H2 H2 ANTICIPATOR 1 POWER SUPPLY. PROVID[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 183 60-2485—8 Fig. 180. Schematic and hookup of T874A,D wit h Q674J. Used in heat pump app lications. H1 FALL L1 (HOT) L2 1 H1 FALL C1 RISE C2 RISE M5957 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FILTER LED ON SOME MODELS. C2 ANTICIPATOR C1 ANTICIPATOR SYSTEM SWITCH [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 184 Fig. 181. Sche matic and hookup of T874K with Q674 C. Used in heat pump applications. Fig. 182. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. FALL CO L1 (HOT) L 2 1 1 H2 FALL H1 FALL C1 RISE 2 3 6 8 9 10 Y G R W W2 A COMPRESSOR FAULT REVERSING VALVE FAN REL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 185 60-2485—8 Fig. 183. Schematic and hookup of T874G with Q674J . Used in heat pump applicatio ns. Fig. 184. Sche matic and hookup of T874A ,F wi th Q674G . Used in st andard applications. L1 (HOT) L 2 1 FAN RELAY SYSTEM SWITCH OFF EM. HT. H1 ANTICIPATOR H1 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT ME[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 186 Fig. 185. Schemati c and hookup of T87 4D with Q674E. Used in standard applications. Fig. 186. Schematic and hook up of T874D with Q674G . Used in standard applications. L1 (HOT) L2 1 SYSTEM SWITCH AUTO H1 ANTICIPATOR H1 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 187 60-2485—8 Fig. 187. Schemati c and hookup of T874C with Q674B. Used in standard applications . Fig. 188. Schematic and hook up of T874D with Q674G . Used in standard applications. L2 1 SYSTEM SWITCH OFF H1 ANTICIPATOR H1 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQ[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 188 Fig. 189. Schematic and hookup of T8 74F with Q674D. Used in standard applications. Fig. 190. Schematic and hookup of T874C with Q67 4L. Used in heat pump app lications. H1 FALL M3960 Y1 H2 W1 1 4 6 8 9 10 FALL Y2 11 W2 RH B R Y L1 L2 RC 5 ANTICIPATOR M839 MOTOR THERMOSTAT SUBBASE SYSTE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 189 60-2485—8 Fig. 191. Sche matic and hookup of T874R with Q674 B. Used in heat pump applications. Fig. 192. Schemati c and hookup of T874D with Q674C. Used in standard applications . L2 1 OFF H1/C1 ANTICIPATOR H1 FALL 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M39[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 190 Fig. 193. Schemati c and hookup of T87 4D with Q674E. Used in standard applications. Fig. 194. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. H1 FALL L1 (HOT ) L2 1 RH W1 W2 G Y2 Y1 RC HEAT RELAY 2 HEAT RELAY 1 OFF HEAT COOL AUTO AUTO ON SYSTEM SWITCH H1 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 191 60-2485—8 Fig. 195. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. Fig. 196. Schematic and hookup of T874G with Q674J . Used in heat pump applicatio ns. H1 FALL O G R E L X W2 FAN RELAY COOL CHANGEOVER VALVE EM. HT. OFF AUTO SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPAT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 192 Fig. 197. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 198. Sche matic and hookup of T874L wit h Q67 4E. Used in standard applications. H1 FALL C1 L1 (HO T) L2 1 G W U B F R T X2 O Y FAN RELAY AUX. HEATER RELAY COMPRESSOR MONITOR OUTDOOR THERMOSTAT OU[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 193 60-2485—8 Fig. 199. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. Fig. 200. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H1 FALL O G R E X FAN RELAY W3 RELAY EM. HT. OFF AUTO SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SW[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 194 Fig. 201. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 202. Schematic and hook up of T874D with Q674G . Used in standard applications. T G R Z X W1 FAN RELAY EM. HEAT OFF SYSTEM SWITCH AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OV[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 195 60-2485—8 Fig. 203. Schematic and hookup of T874 L with Q674C. Used in heat pump applications . Fig. 204. Schematic and hookup o f T874D with Q674F . Used in st andar d applications. CO FALL Y R W OFF SYSTEM SWITCH C1 ANTICIPATOR AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 196 Fig. 205. Sche matic and hookup of T874H with Q674 C. Used in heat pump applications. Fig. 206. Schematic and hookup of T874J with Q674J. Us ed in heat pump applications. H1 FALL G R X1 L Y2 OFF AUTO SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 197 60-2485—8 Fig. 207. Schematic and hookup of T8 74J with Q674L. Used in h eat pump applications. Fig. 208. Schemati c and hookup of T874D with Q674D. Used in standard applications . H1 FALL Y G R E L W2 FAN RELAY COMPRESSOR CONTACTOR OFF COOL SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 198 Fig. 209. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 210. Schemati c and hookup of T874 Y with Q674E. Used in heat pump applic ations. L EM. HEAT OFF SYSTEM SWITCH AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION A[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 199 60-2485—8 Fig. 21 1. Schemati c and hookup of T874G wit h Q674F . Used in standard applications. Fig. 212. Schematic and hoo kup of T874A with Q674E. Used in standard applications. H1 FALL G R L X W2 FAN RELAY W1 RELAY EM. HT. OFF AUTO SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 200 Fig. 213. Schematic and hookup of T874L with Q674C . Used in heat pump app lications. H1 FALL Y H1 R L COMPRESSOR CONTACTOR RELAY 1 N.O. 2 HIGH ON SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO OFF FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 201 60-2485—8 Fig. 214. Schemati c and hookup of T874A with Q674B. Used in standard applications . H1 R L COMPRESSOR CONTACTOR HIGH ON SYSTEM SWITCH COOL OFF FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. M2992 THERMOSTAT SUBBASE SYSTEM COMPONENTS COOL CHANGE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 202 Fig. 215. Schematic and hookup of T874L with Q674B . Used in heat pump app lications. H1 FALL Y H1 R L COMPRESSOR CONTACTOR RELAY 1 N.O. 2 HIGH ON SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR COOL OFF FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 203 60-2485—8 Fig. 216. Schematic and hookup of T874G with Q674J . Used in heat pump applicatio ns. Fig. 217. Sche matic and hookup of T874N with Q674 C. Used in heat pump applications. H1 FALL H2 FALL CO RISE C1 RISE L1 (HOT) L2 1 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 204 Fig. 218. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. L1 (HOT ) L2 1 X L W2 EM. HT. LED (RED) AUX. HT. LED (GRN) AUX. HT. RELAY FAN RELAY "B" RELAY G COOL CHANGEOVER VALVE EM. HT. RELAY COMPRESSOR CONTACTOR O Y E B SYSTEM SWITCH EM. HT. HEAT OFF[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 205 60-2485—8 Fig. 219. Schemati c and hookup of T874C with Q674C. Used in standard applications . M590 1 L1 (HOT) L2 1 FAN RELAY SERVICE LED (RED) FAN SWITCH OFF AUTO SYSTEM SWITCH AUTO C1 FALL H1 FALL 2 4 8 H1 ANTICIPATOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 206 Fig. 220. Schematic and hookup of T874W with Q674C. Used in standard applications. Fig. 221. Sche matic and hookup of T874H with Q674 C. Used in heat pump applications. M5929 H1 FALL L1 (HOT) L2 1 THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 4 6 8 9 10 FAN SWITCH SYSTEM SWITCH AUTO OFF ON AUT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 207 60-2485—8 Fig. 222. Schematic and hoo kup of T874B with Q674E. Used in standard applications. Fig. 223. Schematic and hookup of T8 74S with Q674F . Used in heat pump applications. M5920 L1 (HOT ) L2 1 C W R FAN RELAY COMPRESSOR CONTACTOR 2 HEAT RELAY MALFUNCTION LED (RED) LOW SPEED LED (GREEN) FA[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 208 Fig. 224. Sc hematic and hookup of T8 74A,D with Q674E. U sed in standard applications. M592 7 H1 FALL L1 (HOT) L2 1 L1 (HOT) L2 1 THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 4 6 8 9 10 11 FAN SWITCH SYSTEM SWITCH AUTO ON OFF HEAT AUTO COOL SERVICE LED (RED) COOL CHANGEOVER VALVE COMPRESSOR [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 209 60-2485—8 Fig. 225. Schemati c and hookup of T874D with Q674C. Used in standard applications . M5928 H1 FALL THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 4 6 8 9 10 11 FAN SWITCH SYSTEM SWITCH AUTO ON OFF AUTO SERVICE LED (RED) COOL DAMPER COMPRESSOR CONTACTOR #2 HEAT RELAY #2 FAN RELAY COMPRESSOR CONT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 210 Fig. 226. Schematic and hookup of T874G with Q674G . Used in standard applications . M593 0 H1 FALL L1 (HOT) L2 1 L1 (HOT) L2 1 THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 4 6 8 9 10 11 SYSTEM SWITCH OFF AUTO SERVICE LED (RED) FAN RELAY O COMPRESSOR CONTACTOR #2 HEAT RELAY #2 T RELAY COMPRES[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 21 1 60-2485—8 Fig. 227. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicatio ns. CO (HEAT) FALL H2 FALL RISE H1 FALL L1 (HOT) L 2 1 2 1 2 RISE C1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. W1 - Y1 JUMPER IS Y TERMINAL; REMOVE JUMPER WHEN W1 RELAY[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 212 Fig. 228. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. H1 FALL C1 L1 (HOT) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. REMOVABLE JUMPER (INSTALLED). THERMOSTAT SUBBASE SYSTEM COMPONENTS H2 FALL H1/C1 ANTICIPATOR H[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 213 60-2485—8 Fig. 229. Schemati c and hookup of T874G with Q674F . Used in heat p ump applicat ions. Fig. 230. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . H1 FALL H 2 FALL CO RISE C1 RISE L1 (HOT) L2 1 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECT[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 214 Fig. 231. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. Fig. 232. Schematic and hook up of T874D with Q674G . Used in standard applications. C1 RISE H2 FALL H1 FALL H1 RISE CO L1 (HOT) L2 1 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTEC[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 215 60-2485—8 Fig. 233. Sc hematic and hookup of T874W with Q674L. Used in heat pu mp applications. Fig. 234. Sc hematic and hookup of T874G wit h Q674B. Used in heat pump applications. FAN SYSTEM SWITCH COOL HEAT H1 ANTICIPATOR H1 FALL M395 2 AUTO ON FAN SWITCH R G L Y X H3 E W2 B EM. HT. LED (YELLO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 216 Fig. 235. Schematic and hookup of T 874G an d Q674F . Used in heat pump applications. Fig. 236. Schemati c and hookup of T874 A-D wi th Q674C. Use d in stan dard applications. H2 FALL L1 (HOT) L2 1 R W2 X L G O E Y RTD1 OTD1 EHR1 ODT2 EHR2 RTD2 RTD3 RTD1 SYSTEM MONITOR FAN RELAY RD COOL[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 217 60-2485—8 Fig. 237. Schemati c and hookup of T874C with Q674B. Used in standard applications . Fig. 238. Schematic and hoo kup of T874C with Q674F . Used in heat pump applications. H1 H2 FALL G B R FAN RELAY OFF COOL SYSTEM SWITCH H2 ANTICIPATOR H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITCH 1 [...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 218 Fig. 239. Schematic and hookup of T874R with Q67 4L. Used in heat pump app lications. Fig. 240. Schematic and hookup of T8 74A with Q674W . Us ed in standard applications. L1 (HOT ) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FAN SWITCH AUTO ON[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 219 60-2485—8 Fig. 241. Schematic and hookup of T8 74J with Q674L. Used in h eat pump applications. Fig. 242. Schematic and hookup of T874G with Q674C . Used in standard applications . RISE L1 (HOT ) L2 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FAN SWITCH AUTO ON[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 220 Fig. 243. Schemati c and hookup of T874 G with Q674F . Used in heat p ump applicat ions. Fig. 244. Schematic and hookup of T874J with Q674J. Us ed in heat pump applications. H1 FALL RISE CO L1 (HOT ) L2 1 C1 RISE 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS RE[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 221 60-2485—8 Fig. 245. Schematic and hookup of T874 R wit h Q674L. Used in heat pump applications . Fig. 246. Schematic and hook up of T874C with Q674G . Used in standard applications. H1 FALL L1 (HOT ) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. TERMINAL L[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 60-2485—8 222 Fig. 247. Schema tic and hookup of T87 4W with Q674L. Used in heat pump a pplications. 1 T W3 G R E X1 C B O X2 Y1 Y2 C815A OUTDOOR THERMISTOR AUX. HT. RELAY FAN RELAY EM. HT. RELAY CHANGEOVER RELAY (HEAT) CHANGEOVER RELAY (COOL) COMPRESSOR CONTACTOR 1 COMPRESSOR CONTACTOR 2 EM.HT. AUTO[...]

T874 MULTISTAGE THERMOST ATS AND Q674 SUBBASES 223 60-2485—8 Fig. 248. Schematic and hookup of T8 74Y with Q674F . Used in heat pump applications. M5923 L1 (HOT ) L2 1 C E R FAN RELAY COMPRESSOR CONTACTOR 2 EM.HT. RELAY MALFUNCTION LED (RED) LOW SPEED LED (GREEN) SYSTEM SWITCH HEAT AUTO COOL C2 RISE H1 FALL 2 3 4 8 H1 ANTICIPATOR 1 POWER SUPPLY. [...]

60-2485—8 J.H. Rev . 3-01 www .honeywell.com Home and Building Control Home and Building Control Honeywell Honeywell Limite d-Honeywell Li mitée 1985 Douglas Drive North 35 Dynamic Drive Golden Valley, MN 5542 2 Scarborough, O ntario M1V 4Z9 Printed in U.S.A. on recycled paper containing at least 10% post-consumer paper fibers. T874 MULTISTAGE T[...]