Question about Carrier XHB123D X/Y Series Heat/Cool Air Conditioner

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Carrier Natural Gas Furnace/Air Conditioner, Model 518CXX036000MBAA


Hope you can help with this issue. The fan on my unit runs for hours after the heat turns off. It is an intermittent problem. Sometimes it shuts off, sometimes it doesn't.

First, I made sure the fan was set to auto on the thermostat. I checked the wiring on the thermostat and then replaced the thermostat, to no avail.

I did a little research and found out that my fan limit switch either needs to be adjusted, reset, or replaced. Problem is, I don't know where to look for the switch and I'm not even sure if I can reset or adjust it when I find it.

Thought I would give this a try before I call a pro to come fix it for $200.00 when it could have been something I could have easily taken care of.

Thanks for your anticipated assistance

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Re: Carrier Natural Gas Furnace/Air Conditioner, Model...

Is this a package unit??? Or is it inside the home?? How old is the furnace. The first thing to do is axcess the fan and see if it is controlled by a computer or its old enough to have a fan switch. Trace the red wire from the fan mtr that should take you to the fan switch

Posted on Dec 01, 2007

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