Fan won't stop running

[ideascan]

The fan on my furnace won't stop blowing. I have a Trane BWV724A100D2. With the a/c continuously on it causes the pipes to freeze. Could this be the thermostat or the unit itself? Can someone please help?

[HandymanTrainer]

sounds like a compound problem. T-stat should be set to cool and Auto...if the unit is freezing, then it is not likely making temperature set on stat, and this causes the unit to run forever. If you have faithfully replaced the filter in your unit and the coil is not dirty, then you are most likely low on freon. Freon handling requires an EPA certified technician, but before you call one be sure to leave the unit off long enough to thaw out the frozen coil or you will be paying a tech to stand around and watch ice thaw =)

HandymanTrainer

[ideascan]

Thank you. I have a tech person coming tomorrow. He replaced the fan switch, and will be replacing the thermostat tomorrow. I will have him check the freon level as well. Thanks for your help.

[HayZee518]

why did he replace the fan switch? did it fail? I can't see spending money without a good reason. why change the thermostat? again, did it fail? the thermostat is just a switch. either it works or it doesn't. one of my posts deal with a/c. a refrigeration system is a closed loop of tubing, compressor, evaporator and condenser. the only reason to top off the freon is IF THERE IS A LEAK! The leak must be found or you'll be putting freon in there for the next fifty years! Use yer head! Have the tech examine the system for leaks. They don't want to do it most of the time because it takes time to do the job correctly. They want to get in there, add freon and charge you an arm and a leg for the freon and their time. AND they haven't accomplished anything.

[ideascan]

Thanks for the advice. Yes the fan switch failed. The only way that I was able to cut it off was to switch it off from the circuit breaker. Yesterday, the thermostat stopped switching the unit off. He checked it on Monday when he changed the fan switch. He said I had the wrong theromstat, and that I needed one that was two tiered. (?) I will ask him to check for freon leaks. I have a warrenty on the units, so they will have to do it if I request it.