Bosch GWH 425 EF manual

Water heat ers for u se with Natural an d L.P.G. GWH 425 EF Flow Modulat ed wit h Elec t ronic Ignit ion and Power V ent ing Suit able for heat ing pot able w ater only - Not a pproved fo r spac e heat ing purpose s (Intend ed for vari able flow a pplicatio ns with stea dy cold wa ter inlet t emperatu res) GWH- 425-EF -N GWH- 425-EF -L 6 720 607 01[...]

2 6 720 607 017 WARNING : Improper installation, adjustment , alteration , service or maintenance can c ause injury or property damage. Refer to this manual. For assistance or additional information consult a qualified installer, service agency or the gas supplier . Upon completion of the installation, these instructions should be handed to the use[...]

3 6 720 607 017 425 EF LP and 425 EF NG Specifications W ater C onnection 1 /2” Thread fitting N PT H x W x D 29 3/ 4” x 1 8 1 / 4” x 8 3/ 4" V ent 4” Gas C onnection 1 /2” N PT thread Min. W ater Pressure 1 8 Psi Max. W ater Pressure 1 50 Psi Shipping W eight 50.6 LB Net W eight 44 LB 2.3 G P M at 90 ° rise 4.6 G P M at 45 ° rise [...]

4 6 720 607 017 M I N I M U M I N S T ALLA TIO N C LE AR AN C E S F R O M C O M B U STI B LE AN D N O N CO M B U STI B LE MA TE R IAL S F O R AL C OVE O R C L O SET I N ST ALLA TI O N S FR O NT VI EW S I D E VI EW MO DE L 425 E F * On a combustible wall surface the unit should be mounted away from the wall to provide adequate clearance of the vent [...]

5 6 720 607 017 G E N E R AL R U LE S T O FOLL O W FOR SAF E OP E R A TION 1. Y ou should follow these instructions when you inst all your heater . In the United St ates : The installation must conform with local codes or, in the absence of local codes , the National Fuel Gas Code AN S I Z223. 1 / N F P A 54. In Canada: The Installation should conf[...]

6 6 720 607 017 COMBUSTION AIR REQUIREMENTS The 425 E F water heater holds cold water in its copper heat exchanger and brass water valve when not in use. Because of this, any cold air that comes in through the unit’s vent pipe is capable of freezing these components. This Installation Manual specifies the vent length requirements and the amount o[...]

7 6 720 607 017 Fig. 3 - Incandescent Part icle T ray Illust ration The incandescent particle tray (shipped loose in the carton with the water heater) must be attached at the bottom of the water heater front cover at the time of installation. Use the screws provided. See figure 3. SCREWS INCANDESCENT P ARTICLE TRA Y Fig. 2 - Mounting the Heater WAL[...]

8 6 720 607 017 VENTING WARNING: Do not reduce the vent pipe size and do not common vent with any other vented appliance or stove. This appliance must be vented horizontally to the outside with a sealed 4” single wall vent pipe. The appliance’s flue gasses are under positive pressure and must travel through a single wall 4” pipe that is seale[...]

9 6 720 607 017 Fig 4: S ome V enting Guide Suggest ions An approved side wall vent terminal must be used when the water heater is vented through a side wall. Locate in accordance with AN SI Z223. 1 and local applicable codes. See Fig 5 for restrictions in location of vent terminal in relation to opening doors and windows, grade, and forced air inl[...]

10 6 720 607 017 Fig 5: Side wall exit locations for mechanical draft vent terminals SOFFIT VENT HOOD 7’ MINIMUM ABOVE PUBLIC WALKW AY ONE FOOT ABOVE GRADE 3’ ABOVE ANY FORCED AIR INLET WITHIN 10’ 4’ MIN 1’ MIN 4’ MIN 4’ MIN 4’ MIN 1’ MIN VENT HOOD MUST BE MOUNTED FOUR FEET AW AY FROM DOORS AND WINDOWS VENT HOOD MUST BE MOUNTED FO[...]

11 6 720 607 017 Fig. 6 - Appliance pressure regulator (with directional arrow on reverse side pointing up) GAS LINE SIZING The pressure regulator provided with the heater is adjusted to deliver the proper gas pressure (as indicated on the rating plate and in the manual for altitude up to 2000 feet (660 meters) above sea level. On appliances being [...]

12 6 720 607 017 GAS PIPING, CONNECTIONS Before connecting the gas supply, chec k the rating plate on the right side of the front cover to be sure that the heater is rated for the same gas to which it will be connected. In the United States : The installation must conform with local codes or , in the absence of local codes , the National Fuel Gas C[...]

13 6 720 607 017 Fig.7 - Water valve and water connectors, top view W A T ER C O NNEC T IO NS Install the heater centrally in the building if possible and make hot water piping runs as short as possible When facing the heater , the cold water inlet will be on the right and the hot water outlet on the left.. Although water piping throughout your str[...]

14 6 720 607 017 ELECTRICAL CONNECTIONS WARNING: For safety reasons, disconnect the power supply to the heater before any service or testing is performed. WARNING: This heater must be electrically grounded in accordance with the most recent edition of the National Electrical Code , NF P A 7 0. In Canada , all electrical wiring to the heater should [...]

15 6 720 607 017 OPER A T ING INST RUC T IO NS Before operating the heater , make sure that the system is filled with water . Open the cold water inlet supply to the heater fully . Open a hot water faucet to permit the water to fill the heater and the piping and to eliminate the air trapped in the system Close the hot water faucet after the water f[...]

16 6 720 607 017 Fig. 1 2 - Charact eristic Pilot Flame Flame sensor Piezo Electrode W at e r V alve (Part # 87 07 002802): The water valve on this heater should be ser viced periodically . Lubricate component #36 on page 22 with a small amount of silicon, faucet or lithium grease every two years to keep its o rings fresh and pushrod sliding smooth[...]

17 6 720 607 017 3. Water flow is not sufficient to activate heater . W ater flow rate at faucet is below minimum flow needed to activate heater . When temperature adjustment knob is turned all the way clockwise, the model 425 EF requires 1 /2 gallon per minute flow to activate the heater. As a reference , this is a flow which would fill a quart ja[...]

18 6 720 607 017 Mineral deposits can eventually (3-5 years in hard water areas) corrode the water valve parts to a point where they will need replacing. Any sign of moisture at the bleed hole is a sign that the water valve needs to be replaced immediately. 1 0. Poor circuit connect ions at t he EC O ( overheat sensor ) or the flue gas safety devic[...]

19 6 720 607 017 WA T E R I S T OO HOT 1 . T emperat ure Select ion t oo high T urn the temperature adjustment knob counter-clockwise (to the left) to lower the maximum water temperature. Note: This will increase the activation flow rate. 2. Inlet water temperature is very warm (60°-75°F) Reduce inlet gas supply to lower the heaters degree rise. [...]

20 6 720 607 017[...]

21 6 720 607 017 Fig . 1 5 - Diagram of 425 E F 1 . Heat exchanger 2. Pilot assembly 3. Burner manifold gas pressure test nipple 4. Main gas burner 5. Pilot gas tubing 6. Gas valve 7 . electric control box 8. Power cord 9. on/off switch 1 0. T emperature adjustment selector 1 1 . Microswitch 1 2. Gas inlet gas pressure test nipple 1 3. Exhaust Fan [...]

22 6 720 607 017 Fig. 1 6 - I NTE R IOR COM PO N E NTS D IAGR AM AN D P ARTS LI ST[...]

23 6 720 607 017 Fig. 1 6 INTERIOR COMPONENTS DIAGRAM AN D P ARTS LIST 425 E F 1 Cover 8 705 421 775 2 Temperature a djustment knob 8 702 000 111 3 Temperature adjustment collar 8 700 403 008 4 Draft diverter 8 705 505 451 5 Heat excha nger 8 705 406 235 6 Overheat sensor (ECO) 8 707 206 040 7 Main burner 8 708 120 298 NG 7 Main burner 8 708 120 29[...]

24 6 720 607 017 Fig. 1 7 - Flow chart of 425 EF[...]

25 6 720 607 017 Fift een Y ear Limit ed Warranty General B O SC H P R O water heaters are warranted by the Manufacturer ( B O SC H ) through C ontrolled Energy C orp. C ontrolled Energy Corp . ( C E C ) will furnish a replacement heat exchanger and will furnish a replacement of any other part which fails in normal use and service within the applic[...]

VU L C AN O T ermodomésticos S.A . Estrada de Cacia 380 1 - 8 56 Aveiro - P O RTUGAL Recycled paper © 20 04 C ontrolled Energy Corporation , W aitsfield , V T all rights reserved Replacement Parts available from North American Distributor CONTROLL E D E NE R G Y C OR P . 340 Mad River Park Waitsfield, Vermont 0 567 3 Phone 86 6-33 0-27 30 Fax (80[...]