SunHeater
Post-Purge Overrun / Stuck Relay
Heater fan/blower continues to run for a very long time after burner shuts off
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Control board logic fault, Stuck blower relay, Incorrect thermostat wiring, Overheat condition requiring extended purge
How to Fix / Troubleshooting
Safety: Normal observation is safe; avoid hot surfaces.
- Understand normal behavior: Many SunHeater models run the blower for a short post-purge period (30–90 seconds). Longer runs may indicate a problem.
- Check for overheat codes: Review the display for any overheat or high-limit-related errors that might trigger extended purge.
- Power cycle: Turn off power for 1 minute, then restore. If the blower starts immediately without a call for heat, the blower relay on the Main Control Board may be stuck.
- Inspect wiring: Ensure no external control is backfeeding power to the blower circuit.
- Replace control board: If the blower runs continuously with no call for heat and wiring is correct, replace the main control board.
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Repair Difficulty
Hard
4/5
Required Part
Main Control Board
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