The gas flame is short cycling. The flame stays on for 5 seconds, burns with an acceptable colored flame then shuts off then repeats the process in about 1 minute. I have done the following: Cleaned all lint and residue from all ductwork and all components in the machine. Replaced the 3 gas valve coils(AP4008890), ignitor(304970), burner assembly(AP4044019)and blower wheel(303836). The flame sensor(AP2910747) & Hi-Limit Thermostat (AP4036956) tested good continuity. Checked all wires and connections for solid contact or damage. Operated the machine with the front panel installed to assure proper air flow. The problem remains the same. What would you recommend as my next step?
Answer Hello Tony,
Of course you should check the exhaust duct first since the temperature being held in the unit can cause the issue. Beyond this you should check the following in the following order:
Gas available, igniter, radiant sensor, gas valve, hi-limit thermostat, regulating thermostat, temperature selector switch, timer, cycle selector switch, and the drive motor start switch. I know you already checked some of these in addition to changing some of these out. Obviously, the parts you have already changed are most likely not the issue. The others should have been checked in this order. One of these will be the issue. Let us know if we can assist you further.