Heat pump blowing cold air until unit is jostled.

by Brian
(Sanford, NC)

Rheem model RKMA-A048JK13E exterior heat pump. Thermostat is good (I replaced it to make sure)and functioning properly. The thermostat activates once the interior temperature of the house drops below desired setting. The blower (in the exterior heat pump) begins to blow and continues to blow cold air. There is a humming coming from inside the unit. The ignition sequence doesn't begin and heres the "kicker" (pun intended): when I smack or gently kick the unit, I hear another fan start blowing inside then
I hear the unit ignite and it runs great warming our house to the desired temperature. Then, it turns off and when the interior temperature drops again it just blows cold air until I go smack the unit again. Currently, I open the kids
playroom window and strike the unit with a broom to save the trip around the side of the house.

Other potentially helpful information: the unit sat unused for two years until we bought the house. Prior to us purchasing it, it was serviced and the heating pipes (where it actually ignites) were all changed.