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Repair guides and support for home heating, ventilation, and air conditioning system repair.

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American Standard (Trane) Freedom 90 Furnace will not fire up no heat

My furnace will not fire up (American Standard or Trane Freedom 90) at all. When I turn the gas switch to on and then turn on the power switch I hear a click and then nothing, no other noises, no glow or ignition or anything. If I set the thermostat to have the fan on then the fan does come on and runs. There are lights on the control board so it is getting power. A friend has suggested the control board may be bad and to replace it but I thought I would get a second opinion here just in case. I would hate to replace a part that isn’t the problem. I attached some pictures for reference on the type of furnace it is. I think the red light blinks twice so it is “locked out” but turning the power off (resetting it) even for several hours doesn’t seem to get it out of this mode. Or maybe I’m reading the lights wrong. Any help is greatly appreciated!

Edit: I added a video of the startup code. I really hope it’s not the control board because I can’t find the replacement part it may be too old to buy a new one.

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I have had a couple of units go bad because of bad solders on a molex type connector on the PCB. It looks like there are 4 of them on that board. The ones on the bottom left and right are the most suspect, but do them all. Carefully photo the PCB and wiring for reference to reassemble. Remove the PCB and focus on a large white connector. Remove the conformal coating from the back connections, then resolder all the pins on the connector. If you take a glass to it you may be able to see the breaks but it is very subtle. Then try again.

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Do you agree that it is most likely the board that is bad then?

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@tonedub do not go throwing parts at this. There are multiple reasons it could lock out. Induced draft motor not working. Sensors failed. I'm not sure exactly what type of ignitor this model has as I don't have a model number but that could have failed. There could be something blocking the exhaust pipe, like an animal or something. Solenoid on gas valve could have failed. These are all possibilities I've seen time and again. Weirdest one was induced draft motor wouldn't run because a lizard had died in it during the summer and jammed it.

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I removed and tested the igniter with a digital multimeter for continuity and I am only getting a reading of under 17ohms? According to everything I can find it should be at least 35-75 range?

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I have same unit and have had the sissue of the unit starting and staying running for very long due to either the harnesss not making contact or the circuit board not making contact over and over ,

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