Carrier Control Board Fuse Blows
I have a Carrier Heat pump with electric heat strips to supplement. Two nights ago the heat went off during the night and I woke up to fifty some degrees in the morning (normally it would not cool off that much here, but we just had that cold snap so it was about 28 degrees outside). I noted that the Thermostat was blank, but had to leave for work. After work I took the cover off the airhandler and found that the 5 amp fuse on the control board was blown. I replaced the fuse and it ran till the house was warm, it ran several times during the evening. At bedtime I noticed that it was getting cool in the house and sure enough the Themostat was blank again. I replaced the fuse again and it blew within five minutes.
After work today, it checked all of the thermostat wires (both to the thermo and to the heat pump) for shorts and found none. I pulled the plug at the heat pump and put a new fuse in then turned the thermostat to EMRHT and it seems to be working now. It has been about 3 hours and the furnace has run several times.
What is the next step? I guess I'll plug the heatpump back in tomorro evening and see what happens. If the fuse blows again is there something I can check or is it time for a new control board?