Bang the side of the heater and it works

crwalker

A month or so ago my heater stopped working. I went into the basement and inspected, took the panel off and held the button the door pushes closed and lights came on in the panel, but no flame/blower, etc. The light labeled flame would not come on. Called hvac guy who came out and inspected; took the door off and put it back on and it fired up. He said the doors were warped a bit so straightened them by bending. I understood the theory was that they were warped, thus not pushing in the button correctly. I wasn't convinced because it this were the case, then it should work by pushing in the button manually. Hell, he got it working though so I wasn't arguing. It worked fine for a month or so. Recently, failed again. I went down and banged the door on the side (implementing his warped door theory). Wow, it worked. Went back inside and went to bed. Woke up in a cold house. Went down, banged the side, it worked again. I've narrowed it down that the door is a red herring. As long as the button is pushed down and you bang the side of it, the flame and blower fires on, but when it reaches temperature and shuts off naturally, it cannot restart via thermostat data prompting it to fire back up. It may be a loose wire or the like, but I'm worried some safety issue with the flame, etc. preventing it from coming back on. Way over my comfort level to handle by myself, so I would like to call the same guy back and give him new data. Just want to know the possibilities here so I can tell whether he knows what he's doing.

Any comments or suggestions would be greatly appreciated.

Cheers

Jackofall1

Well the way I see it, you have (2) choices, you can hire a left handed dwarf who's sole purpose in life is to bang on the side of your warped door to keep your furnace going or better solution, fix the door and related switch so they make positive contact.

Mark

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how

If you have no visable flashing light diagnostic system, turn the power off to the furnace. Electrically isolate & bypass the door switch to test out your door switch theory. Tape any exposed connections you make. Put a sign on the furnace door saying that the door switch has been bypassed and wait.
If the heating problem goes away then you know you need to replace the switch. If it continues then you know you have something else that's loose that responds to vibration and you should hook the door switch back up the way you found it. Check the snuggness of all electrical connections especially the green ground wire. Beyond that it's bringing in someone who doesn't need any suggestions from here!

crwalker

Thank you for your responses. I'll opt to fix it so I don't have to put up with HR-related dwarf drama. On a new note, I isolated the problem to one of the electrical wiring harnesses. No problem with the switch. I checked all of the electrical connections as suggested. All secure and nothing kicked on while checking the connections. Afterward, I grabbed one of the bundles of wires with my hand. When I lifted the bundle upwards, it triggered on the flame and blower. Must be a short or the like in one of the wires in the bundle that deals with firing it up. A bang to the side or moving the harness completes the circuit allowing it to fire up until reaching the set temp. After it shuts off it needs the bundle to move to complete the circuit. Any idea on which component this wire would go to? This is for curiosity sake and so I can articulate it to the professional? I don't mess with electricity other than simply stuff.

how

Telling him what you told us will be enough. He'll know he's probably dealing with a loose pin connection in the harness.

Tator1076

Was that harness on the board? Is that unit a goodman? If so need replace the board.