33 11112014GW
Code 71 Troubleshooting Procedure
SV0, SV1, SV2, SV3 Solenoid Valve Fault
WARNING: Turn off the electrical, gas and water supply to the water heater before proceeding.
1. Check wiring harnesses to SV0, SV1, SV2 and SV3 for loose, broken or damaged connections
from gas valve solenoids back to PC board.
2. Check for moisture in plastic tubing on internal units from bottom of combustion box back to
gas valve. If moisture is found in this tube replace gas valve. In addition; remove burner
manifold and burner assembly to determine what is causing the moisture. Look for a leaking
heat exchanger or condensation coming from the vent system.
If the heat exchanger is leaking replace it and any other components damaged due to that leak.
If the moisture is caused by condensation running back into the unit from the vent system make
provisions to stop this by installing a condensate drain line at the top of said unit.
3. Check voltage to SVO and SV1 while unit is trying to fire. If you have proper voltage but keep
getting an error code proceed to item 4 below.
4. Measure the resistance of SV0, SV1, SV2 and SV3 if any of the solenoid valves are found to be
open, meaning having no resistance replace the gas control valve.
5. If you are still getting a code 71 replace the gas control valve. You may get a good resistance
reading upon unplugging the wires, however under load it could open or you may have a
mechanical problem inside the valve that won't allow the valve open.
6. Replace PC board
To Next Page
Loading...
Need help?
General
