I have a Carrier Heating/AC Unit that the blower fan will not shutoff. The unit was running, then the heat turned off but the blower fan did not. Now the blower fan is on all the time and the heat or A/C will not come on. In order to get the blower fan off I have to cut the power to the unit at the main house breaker. This unit is the type that mounts on the roof. I have replaced the thermostat and this changed nothing.
The model number is: 48NMT036---301BE

Here is a link to the circuit board diagram:
http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/wd584a.18.1.pdf

The Circuit board number is: 316457-401

I have a Carrier Heating/AC Unit that the blower fan will not shutoff. The unit was running, then the heat turned off but the blower fan did not. Now the blower fan is on all the time and the heat or A/C will not come on. In order to get the blower fan off I have to cut the power to the unit at the main house breaker. This unit is the type that mounts on the roof. I have replaced the thermostat and this changed nothing.
The model number is: 48NMT036---301BE

Here is a link to the circuit board diagram:
http://www.xpedio.carrier.com/idc/groups/public/documents/techlit/wd584a.18.1.pdf

The Circuit board number is: 316457-401

If you have replaced the thermostat, the only thing remaining is the air handler/inside unit fan timer circuit board. It will usually cost about $50. I recently had the same problem with a carrier Heat Pump/Air Handler. Mine would not cut on. Replacement of it solved the problem. Good luck!

If you have replaced the thermostat, the only thing remaining is the air handler/inside unit fan timer circuit board. It will usually cost about $50. I recently had the same problem with a carrier Heat Pump/Air Handler. Mine would not cut on. Replacement of it solved the problem. Good luck!

Thanks for the reply. I called a local place about the circuit board and was quoted $180 for the circuit board and another $100 for the piggy back board. Is there more than one circuit board? The only one that I have seen is the one that the thermostat wires go to.

Hi

I had the same problem and haven't been able to solve mine either. What did you do to solve this problem?