A.O. Smith HW-120M manual

1 P ART NO. 21 2626- 000 PRINTED IN U.S.A. 0905 SUPERSEDES P ART NO. 19201 1- 000 REV . 4 MODELS HW-120M, 160M, 200M, 225M COMMERCIAL GAS COPPER HEA T EXCHANGER W A TER HEA TER BURKA Y UP-FLOW MODELS Including Models with Intermittent Pilot Ignition (I.I.D.) A DIVISION OF A.O. SMITH CORPORA TION McBEE, SOUTH CAROLINA, USA RENTON, WA, USA STRA TFORD[...]

2 ROUGH-IN-DIMENSIONS HEA TER PERFORMANCE DA T A NOTE: T o compensate for the effects of high altitude areas above 2000 feet, input rating, and therefore recovery ratings, should be reduced approximately 4% for each 1000 feet above sea level. Recovery rating of models shown in chart above are obtained by actual efficiency test dat a by recognized C[...]

3 FOREWORD This design complies with the latest edition of the ANSI Standard Z21.10.3 for gas water heaters V ol. III S torage W ater Heaters with input ratings above 75,000 BTU per hour Circulating and Instantaneous. Detailed installation diagrams are in this manual. These diagrams will serve to provide the installer with a reference for the mater[...]

4 SHOULD OVERHEA TING OCCUR OR THE GAS SUPPL Y F AIL TO SHUT OFF , TURN OFF THE MANUAL GAS CONTROL V A L VE TO THE APPLIANCE. Heater must be protected from freezing downdrafts during shutdown periods. GROUNDING INSTRUCTIONS This water heater must be grounded in accordance with the National Electric Code and/or local codes. These must be followed in[...]

5 AUTOMA TIC GAS SHUT OFF CONTROL The automatic gas shutoff control, fig. 1, is an automatic safety device which activates at a water temperature of approximately 195 0 F (90.5°C). This limits the water outlet temperature to a maximum of 200 0 F (87.7°C). The device is wired in series with the gas valve. The control will automatically reset when [...]

6 4. Discontinues ignition spark when the pilot flame is established. The S-8600 control used on propane gas models provides safety lockout if the pilot fails to ignite within the pilot flame establishing period. The S-8600 control used on natural gas models continues trial for ignition until pilot flame is established. 5. After proof-of-pilot flam[...]

7 CAUTION Any part of the paddle must not touch the pipe or any restrictions in the pipe. Screw the flow switch in position so the flat of the paddle is at right angles to the flow . The arrow on the side case must point in the direction of the flow . The safety flow switch may be field adjusted to obtain higher minimum flow rates than those shown [...]

8 INST ALLA TION INSTRUCTIONS IMPORT ANT Strict adherence to installation wiring diagrams shown in this manual is required to prevent constant pump operation when the system temperature control is satisfied, otherwise the warranty is void as stipulated under item 2a (6) of the LIMITED WARRANTY . REQUIRED ABILITY INST ALLA TION OR SERVICE OF THIS W [...]

9 CONFINED SP ACE When drawing combustion and dilution air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE IN OR WITHIN 12 INCHES (30.5cm) OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of at least one square inch per 1000 Btuh (2,225mm 2 /Kw)of the[...]

10 Y our local code authority may have other specific relief valve requirements not covered in this section. THE PURPOSE OF A RELIEF V AL VE IS TO A VOID EXCESSIVE PRESSURE OR TEMPERA TURE INTO THE STEAM RANGE, WHICH MA Y CAUSE SCALDING A T FIXTURES, T ANK EXPLOSION, SYSTEM OR HEA TER DAMAGE. TO A VOID SCALDING OR WA TER DAMAGE, A DRAIN LINE MUST B[...]

11 PIPING DIAGRAMS (USE THIS DIAGRAM FOR STRAIGHT RECOVERY SYSTEMS SUPPL YING HOT W A TER A T ONE TEMPERA TURE ONL Y) FIGURE 7 DANGER TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE A T FIXTURES. SEE W A TER TEMPERA TURE CONTROL W ARNING ON P AGE 19. IF HIGHER PREHEA T TEMPERA TURES ARE NECESSARY TO OBT AIN ADEQUATE BOOSTER OUTPUT , ADD[...]

12 FIGURE 8 DANGER TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERA TURE A T FIXTURES. SEE W A TER TEMPERA TURE CONTROL W ARNING ON P AGE 19. IF HIGHER PREHEA T TEMPERA TURES ARE NECESSARY T O O BT AIN ADEQUATE BOOSTER OUTPUT , ADD AN ANTI-SCALD V A LVE FOR HOT W A TER SUPPLIED TO FIXTURES.[...]

13 FIGURE 9 FIGURE 10 DANGER TEMPERA TURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERA TURE A T FIXTURES. SEE WA TER TEMPERA TURE CONTROL W ARNING ON P AGE 19. IF HIGHER PREHEA T TEMPERA TURES ARE NECESSARY T O OBTAIN ADEQUA TE BOOSTER OUTPUT , ADD AN ANTI-SCALD V AL VE FOR HOT W A TER SUPPLIED TO FIXTURES.[...]

14 GAS CONNECTIONS W ARNING THE INLET GAS PRESSURE MUST NOT EXCEED THE V ALUE SPECIFIED BY THE MANUF ACTURER ON THE RA TING PLA TE (10.5" W .C. - NA TURAL GAS, 13.0" W .C. - PROP ANE GAS). EXPOSURE T O HIGHER GAS SUPPL Y PRESSURE MA Y CAUSE DAMAGE T O THE GAS V A L VE WHICH COULD RESUL T IN FIRE OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED [...]

15 ELECTRICAL WIRING D IAGRAMS FOR THE HW-120M, 160M, 200M AND 225M WA TER HEA TERS I.I.D. SYSTEM (NA TURAL) FIGURE 1 1 A minimum gas supply pressure of 4.5" W .C. (1.12kPa) for natural gas and 1 1" W .C. (1.74kPa) for prop ane gas is required for purposes of input adjustment. ELECTRICAL INFORMA TION ALL ELECTRICAL WORK MUST BE INST ALLED[...]

16 ELECTRICAL WIRING DIAGRAMS FOR THE HW -120M, 160M, AND 200M W A TER HEA TERS I.I.D. SYSTEM (PROP ANE) FIGURE 12 NOTES:[...]

17 OPERA TION IMPORT ANT Only qualified personnel shall perform the initial firing of the heater . At this time the user should not hesitate to ask the start-up technician any questions regarding the operation and maintenance of the unit. Lighting and Operating instructions are included with this manual. By using these instructions, the user may be[...]

18 OPERA TING INSTRUCTIONS FOR I.I.D. MODELS The I.I.D. models have an automatic intermittent spark ignition system, figure 3, mounted on the jacket at the front of the heater which ignites the pilot gas whenever system controls call for heat. S t art the unit in accordance with the instructions on the operating label att ached to the heater . Thes[...]

19 DANGER HOT W A TER TEMPERA TURES REQUIRED FOR AUTOMA TIC DISHW ASHER AND LAUNDRY USE CAN CAUSE SCALD BURNS RESUL TING IN SERIOUS PERSONAL INJURY AND/ OR DEA TH. THE TEMPERA TURE A T WHICH INJURY OCCURS V ARIES WITH THE PERSON’S AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR DISABLED PERSONS INCREASES THE HAZARDS T O TH[...]

20 SER VICE INFORMA TION The installer may be able to observe and correct certain problems which may arise when the unit is put into operation. HOWEVER, it is recommended that only qualified service personnel, using appropriate test equipment, be allowed to service the heater . Any safety devices used in conjunction with this appliance should recei[...]

21 PILOT BURNER USED ON I.I.D. SYSTEMS FIGURE 15 PROTECTOR SWITCH (Coil High Limit - All Heaters) If the protector switch, fig 2, should shut off unit, check for the following conditions: 1. No water in heater . 2. Restricted water flow through the heater . 3. Excessive liming. 4. Improper wiring (automatic gas shutoff control acting as primary con[...]

22 PREVENTIVE MAINTENANCE RECOMMENDED PROCEDURE FOR PERIODIC REMOV AL OF LIME DEPOSITS FROM COIL TYPE COMMERCIAL W A TER HEA TERS The amount of calcium carbonate (lime) released from water is in direct proportion to water temperature and usage, see fig. 17. CAUTION DO NOT USE A NYLON BRUSH OR OTHER STA TIC CREA TING MA TERIAL TO CLEAN DUST AND CARB[...]

23 The usage of water softening equipment greatly reduces the hardness of the water . However , this equipment does not always remove all of the hardness (lime). For this reason it is recommended that a regular schedule for deliming be maintained. The time between cleaning will vary from weeks to months depending upon water conditions and usage. A [...]

24 CHART 1 - CER-TEMP 80 RECOVER Y SYSTEM CHECKOUT PROCEDURE (Use this checkout for Cer-T emp 80 Recovery Systems) CHECKOUT The checkout sequence should be used as an on-the-job trouble- shooting guide to identify the cause of incorrect system operation and suggest a remedy for its correction. Because improper piping and wiring can result in unsati[...]

25 CHART 2 S8600 (NA TURAL GAS AND LP GAS) INTERMITTENT PILOT SYSTEM TROUBLESHOOTING NO SP ARK A T PILOT BURNER T urn gas supply off. Is voltage (24 V ac) across the 24 V terminals on “Call for heat”? Is voltage (24 V ac) across the PV & MV/PV terminals on “call for heat”? NOTE: (FOR LP MODELS ONL Y) Pilot valve will be de-energized if [...]

26 CHART 2 S8600 (NA TURAL GAS AND LP GAS) INTERMITTENT PILOT SYSTEM TROUBLESHOOTING Ensure all manual shutoff valves are fully open; All filters are clean; All gas connections are gas tight; Pilot tubing is not damaged, obstructed or kinked; and pilot orifice is unclogged. Check for air in gas line, purge (bleed) line if necessary . Are the wires [...]

27 CHART 2 S8600 (NA TURAL GAS AND LP GAS) INTERMITTENT PILOT SYSTEM TROUBLESHOOTING PILOT BURNER LIGHTS BUT MAIN BURNER DOES NOT LIGHT Does the pilot flame cover 3/8” to 1/2” of igniter/sensor rod? Does spark stay on for more than 30 seconds after the pilot is “proven” (lit)? Is the pilot burner ignition cable in good condition (not brittl[...]

28 MODEL HW LIMITED W ARRANTY A. O. Smith Corporation, the warrantor , extends the following LIMITED W ARRANTY to th e owner of this water heater . 1. If within FIVE years after initial installation of this water heater , a heat exchanger , coil or gas burner shall prove upon e xamination by the warrantor to be defective in material or workmanship,[...]