Hi everyone. I recently had something unusual happen to my heat pump. It's a Trane Executive and it's the original heat pump that was installed in my home 25 years ago. Yes, it's old!
The problem I'm having seems to be related to the very cold weather we had last week. Because of the cold weather and windy conditions, my heat pump was running almost non-stop for several days. Late last Friday evening I noticed that the condenser fan was not running. It was not a defrost cycle because I went outside and checked the coolant lines and one (large one) was hot and the other (small one) slightly warm. While outside, the fan started running again and then seemed to slow down and speed up. Then after a couple minutes, the fan ran progressively slower and slower until it stopped. I tried turning the fan manually, but it wouldn't move.
At that point I thought that the fan motor had seized up, so I switched the system to emergency heat until the next day. The next day I turned the system back to normal mode. The compressor started, but the fan did not start, and the fan still could not be turned manually. I switched back to emergency heat. On Sunday the weather was a bit warmer, so in the middle of the afternoon, I decided to try the heat pump in normal mode one more time. The outside unit started and the fan was running again at normal speed. It's now 5 days later and the heat pump's been working fine.
Anyone have any idea what would cause the condenser fan motor to seemingly seize up and then run normally two days later?