GE Gas Fired Warm Air Furnace / Fan and Limit Control Issues


Old 02-07-13, 07:26 PM
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GE Gas Fired Warm Air Furnace / Fan and Limit Control Issues

I have tried to do my research prior to this post. I am hoping this helps me and anyone who can help.

I have a GE Gas Fired Warm Air Furnace. From the GE Plate inside the unit, it states the Model Number is: 21LU105A2A3.

My problem is that the knob (which used to be orange) that adjusts the fan broke off. So I turned the power off to the unit, removed the cover plate for the fan and attempted to adjust it by using a small pair of pliers. There are two round knobs, almost look like screws with blue middle tips. One is on the top (next to it is marked fan) the other on the bottom (next to it is marked limit). I was trying to adjust the fan and turn it back to off, it was previously on a setting to where it was constantly blowing. In the process, I accidentally adjusted the bottom screw which I believe is for the limit. When I turned the unit back on, not only does the fan still continue to run non-stop. But now the air is consistently cool.

I have attached 3 photos. One is of the fan control unit itself, the other is of the fan cover. The third photo is of the wiring diagram I found taped inside the furnace.

I have tried to find parts for this unit, manuals, etc. I believe due to it's age I am sorta out of luck here. The unit runs very well and I am a very abled DIY'r. I just need to be educated on how to adjust the fan and limit without the knob.

Thank You in advance to anyone that can help!!
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Old 02-07-13, 08:44 PM
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I think it's more than adjusting it...... it sounds like it needs to be replaced.
Old 02-08-13, 02:33 PM
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Lots of fan switches can be made to work in your furnace.

I'd take the old fan switch in to a furnace parts distributor and have them choose a suitable replacement for you.

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