80 NPE Service Manual
Failure mode Cause Check method
Ignition failure
Main gas valve
1. Check the primary/secondary power supply to the main gas valve.
●
Check, with a multimeter, if the input power is DC 22-24 V.
2. Replace the PCB if power is not supplied.
3. If power supply is normal, check if the coil is open.
4. Check if the solenoid valve works properly.
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Feel or hear a click.
Gas block Check if the coil is open Check the voltage of the solenoid valve /
White-Yellow , White-Red
Repeated ignition-out
Flame sensing error
1. Check the location of the flame, if there is any deformation or foreign substance,
repair or replace the part.
2. Check the flame rod wire for proper connection and/or damage.
3. Check the grounding to the water heater case to verify proper grounding at the
outlet.
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If the ground wire is improperly connected or not making a good connection,
remove and reattach the ground wire ensuring good contact with the case.
●
Or use a multimeter to measure the flame sensing current (normally 3~4 µA).
Measuring flame current Grounding wire position
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