STEADY ON
Tappan
Internal Control Board Failure / No Self-Diagnostics
LED on Tappan control board is solid ON with no flashes; furnace does not respond to thermostat.
Advertisements
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.
Advertisements
Possible Causes
Failed microprocessor on integrated furnace control, surge damage, shorted low-voltage circuit locking the board
How to Fix / Troubleshooting
Safety: Turn off power before handling the control board.
Steps:
- Verify 120 VAC is present at the board's L1 and neutral terminals and 24 VAC is present at R and C. If either is missing, correct the power supply issue first.
- Disconnect thermostat wires from R and W at the board, then jumper R to W directly to simulate a heat call. Restore power. If the furnace still does not respond and the LED remains solid, the board is likely defective.
- Inspect the back of the board for burned traces or components. If found, replace the board with an OEM Tappan-compatible control.
- When replacing, transfer each wire one at a time from the old board to the new board, following the wiring diagram on the furnace door.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Integrated Furnace Control Board
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements