Bosch GWH 425 HN User Manual
Bosch water heater user manual model 425hn
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Also See for GWH 425 HN:
- Applications manual (50 pages) ,
- Manual (29 pages) ,
- Service bulletin booklet (23 pages)
Table of Contents
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Table of Contents
Troubleshooting
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Summary of Contents for Bosch GWH 425 HN
- Page 1 Water heaters for use with Natural and L.P.G. GWH 425 HN Flow Modulated with Electronic Ignition Suitable for heating potable water only - Not approved for space heating purposes (Intended for variable flow applications with steady cold water inlet temperatures)
- Page 4 FRONT VIEW SIDE VIEW...
- Page 9 MAXIMUM INLET GAS FLOW PRESSURE SETTING 2.000 ft - 4.500 ft Above 4.500 ft consult your local gas provider. GAS INLET PIPE PRESSURE TAP PLASTIC VENT CAP PRESSURE REGULATOR (with directional arrow on reverse side pointing upward) Altitude Natural Gas inches W.C: 0' - 2.000 ft 5.7"...
- Page 10 Nominal Iron Pipe Internal Size, Diameter inches inches 0.364 0.493 0.622 0.824 1.049 1 1/4 1.380 1050 1 1/2 1.610 1600 1100 2.067 3050 2100 1650 2 1/2 2.469 4800 3300 2700 3.068 8500 5900 4700 4.026 17,500 12,000 9,700 8,300 Length of Black Iron Pipe, Feet 1450 1270 1150 1050...
- Page 12 - on - off...
- Page 13 PILOT ORIFICE Correct gap between pilot burner tip and electrode tip Piezo Electrode Flame sensor Piezo...
- Page 15 It is extremely important for a tankless instantaneous water heater to have the right size gas line to obtain correct pressure...
- Page 16 Do not add any flow restrictor to the shower head.
- Page 17 6 720 606 804-10.1AL...
- Page 19 Cover Temperature adjustment knob Temperature adjustment collar Draft diverter Heat exchanger Main burner Main burner Burner assembly washer Throttle disc Pilot burner Pilot burner Pilot electrode Pilot orifice Pilot orifice Pilot tube Washer pilot tube Gas valve Gas valve Diaphragm switch Diaphragm switch Pilot electrovalve Burner electrovalve...
- Page 24 † † † † © † †...
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Questions and answers
I removed the unit for the wall for renovation. When I put it back up it work for the first few times. On the last test run it came on like normal but when I shut it off the gas stayed on.
The Bosch GWH 425 HN gas unit should turn off when the ON/OFF switch is set to the OFF position and the gas valve is shut off. If the unit stays on after shutting it off, possible reasons could include:
1. Faulty ON/OFF Switch – The switch may not be functioning properly, preventing the unit from shutting down.
2. Gas Valve Issue – If the gas valve does not fully close, gas may continue flowing to the burner.
3. Flue Gas Sensor Malfunction – If the sensor incorrectly detects inadequate venting, it may cause unintended operation.
4. Negative Air Flow – Poor venting can result in improper burner shutdown.
A qualified service technician should inspect the unit to diagnose and fix the issue.
This answer is automatically generated