Trane Heat Pump time delay between OD fan cut on and solenoid deenenergizing

by Thomas
(Elkton, Virginia)

I have a Trane TWR736A100A1 heat pump. At the conclusion of the defrost cycle, the defrost control board has a time delay between the OD fan cut on and the reversing valve solenoid deenenergization. In temperatures below 34 degrees, this delay causes the head pressure to drop, causing the reversing valve to hang in cool position after the defrost is complete. The charge is chart perfect. The coils are spotless. The TEX used in heat pump mode is fed with 14 degree subcooled liquid. The superheat is variable from 2 degrees (at 20 degrees outside) to 25 degrees (at 50 degrees outside). I suspect if I could have the OD fan and the solenoid act at the same time the reversing valve would switch correctly. The control board for this unit has no adjustments at all. Any ideas to help??

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Heat Pump Defrost Problems.

Share this page:
Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.