I have a Trane XL 1400 heat pump with the model number TWY048B100A1. In winter the system frequently blows out cold air in the house; when it is really cold out, it seems to blow out cold air for 15 minutes every 30 to 45 minutes. I looked at the system closely and found that the emergency heat electric heating coils are broken and the fan on the outdoor compressor unit runs a defrost cycle about every 30 minutes for 15 minutes. During this defrost cycle, the compressor unit fan runs.
I found that there is a defrost control board with the model number cnt02941.
I also found a manual that explains that the outdoor fan should not run during the defrost cycle here: http://docslide.us/documents/heat-pump-defrost-control-book34-4101-07.html
Since the fan is running during the defrost cycle, it seems that the outdoor coils are not able to heat up to the required 50°F and the board uses a time override feature that prevents the system from being locked into a defrost cycle.
The manual states that if the fan runs during the defrost cycle, to replace the defrost control board in multiple places.
I replaced the board and ran a forced defrost cycle. During this test, the fan continued to run during the defrost cycle, making it seem that it is not the board. In other words, the new board does the same thing as the previous board.
Can anyone confirm that the fan should not run during the defrost cycle?
I found that there is a defrost control board with the model number cnt02941.
I also found a manual that explains that the outdoor fan should not run during the defrost cycle here: http://docslide.us/documents/heat-pump-defrost-control-book34-4101-07.html
Since the fan is running during the defrost cycle, it seems that the outdoor coils are not able to heat up to the required 50°F and the board uses a time override feature that prevents the system from being locked into a defrost cycle.
The manual states that if the fan runs during the defrost cycle, to replace the defrost control board in multiple places.
I replaced the board and ran a forced defrost cycle. During this test, the fan continued to run during the defrost cycle, making it seem that it is not the board. In other words, the new board does the same thing as the previous board.
Can anyone confirm that the fan should not run during the defrost cycle?