Honeywell S8610U Error Codes: Green LED Flash Codes

2 flashes: let it retry, or restart the call for heat

Resideo says the control tries to light the pilot, and if the pilot does not light or is not sensed, it shuts off the spark and the pilot gas and waits five minutes before another try. It keeps doing that until the pilot lights or the call for heat ends. The five minute delay can be skipped by cycling the thermostat, or by removing and restoring the system power.

If it fails to light on the next try, Resideo’s service list is the gas supply, the pilot burner, the spark and flame sense wiring, a flame rod that is dirty or out of position, and the burner ground connection. Those are a technician’s checks.

3 flashes: the flame went out while running

The control starts a new trial for ignition at once, and the code stays through it until the flame is proved. If it fails to light on the next trial, Resideo’s list is the gas supply, the pilot burner, the flame sense wiring, a dirty flame rod and the burner ground connection, for a technician.

4 flashes: a flame when there should be none

The control has sensed a flame out of sequence. If it clears within 10 seconds, the control goes back to its normal sequence; if it lasts longer, the control waits until 1 hour after the error is corrected.

Resideo’s service action is to check for a pilot flame and replace the gas valve if one is present; if there is none, cycle the call for heat, and replace the control if the error repeats. A flame that should not be there is a call for a technician, and if you smell gas, follow the steps in the warning above.

5 flashes: the vent damper

Code 5 is a damper error: a damper is required but not present, or it failed to open or to close within 60 seconds. Once the damper error corrects, the control goes back to normal. Resideo’s service actions are the damper connection, the damper wiring and the 24 volt connection on the control, then replacing the damper if needed.

Resideo also says that once the control has completed 10 ignition cycles with a vent damper connected, it will not work without one. So a damper that was unplugged or removed brings this code, and the damper has to be connected again. That is a technician’s job: Resideo says to disconnect the power supply before making any wiring connection.

6, 7 or 8 flashes: wait mode

For all three, the control stays in wait mode and resumes normal operation when the fault corrects. For 6, a control internal error, Resideo’s step is to cycle the call for heat, and to replace the control if the error repeats.

For 7, a flame rod shorted to ground, Resideo’s checks are the flame sense lead for damage or shorting, the flame rod’s position, and its ceramic for cracks, damage or tracking. For 8, a low secondary voltage supply, they are the transformer and the AC line, checked with the full system load. Both are technician work.