I live in Tennessee and we are getting temps in the 20's. I have two heat pumps, one for 1st floor and one for 2nd floor. The 1st floor unit seems to run fine, the 2nd floor outside unit does not run at all. It has been this way for a few weeks. On this unit the inside air handler and aux elec. heat is all that is working right now. I would like to check whatever I can prior to calling my service co. Any Ideas? Thanks