bradrm Report post Posted August 16, 2014 I have a Duo Therm heat pump that is not working as expected. The front system is running in "Aux Heat" mode, so the furnace runs when I set the CCC for heat pump to run. The rear heat pump runs normally. I understand that when the temperature drops below 30 degrees the heat pump will switch to Aux Heat but where I am located night time temps are in the high 50's. I suspect that I may have a bad temp sensor causing this. How can I find out what is happening here? Share this post Link to post Share on other sites
kaypsmith Report post Posted August 17, 2014 A bad, or not working reversing valve can cause this to happen on a heat pump, assuming the air conditioning part is working and getting cool correctly. If A/C doesn't work correctly, the heat side of a heat pump can't either. Assuming that it has worked correctly in the past, then suddenly started this. If it has never worked correctly, could be wired incorrectly, and yes, could be an outside temp sensor not working correctly. Share this post Link to post Share on other sites
