Help Needed With Older Goodman Furnace

Morrow GA

Description

Looking for someone to diagnosis this issue that might have experience with older model Goodman gas furnaces. The unit has a delayed ignition issue. The burners were cleaned of soot and ash along with the burn area. The pilot unit, tubing and thermocouple were replaced. The control value was changed about 3 years and seems to in working order. The pilot unit is free standing inside the burning area as there is nowhere to bolt it down, but it was moved closer to gas flow direction to the right. The unit did not have a delayed ignition problem last winter, but the pilot tubing was worn near the pilot so that was replaced. Regardless of the changes, the unit still started up with the same loud boom as before cleaning and changing parts. But this time instead of continuing the flame it completely shuts off the gas. A dirty flame sensor would cause this on newer models but this unit doesn't appear to have that type of senor although there has to be some type of sensor in place to shut off the gas, besides the thermocouple. Thanks in advance for your help and time!