Atwood 8500 Furnace
Working on a Friends furnace. Here is the issue. -turn the thermo on for heat and the furnace starts -fan spins ignitor sparks and gas flows -you can feel heat at the exhaust -after about 10 sec...
Forum Discussion
NOT the Sail Switch
1. The Spark Electrode could be bad or incorrectly gapped (enough gap to light the burner but too close to the burner to correctly sense the flame to send the signal back to the Ignitor module) VERY RARE!
2. The WIRE from the Ignitor board to the Spark Electrode could be bad and "leaking" the return AC flame sense circuit.
3. The Control Board is bad. Doug
You obviously have an older model because the newer models shut the fan OFF after the 3rd attempt. IF the Control module is bad, you can install the newer board and rewire to the newer style to kill the motor after 3 attempts.
1. The Spark Electrode could be bad or incorrectly gapped (enough gap to light the burner but too close to the burner to correctly sense the flame to send the signal back to the Ignitor module) VERY RARE!
2. The WIRE from the Ignitor board to the Spark Electrode could be bad and "leaking" the return AC flame sense circuit.
3. The Control Board is bad. Doug
You obviously have an older model because the newer models shut the fan OFF after the 3rd attempt. IF the Control module is bad, you can install the newer board and rewire to the newer style to kill the motor after 3 attempts.
