Hi, the outdoor unit will not come on. We hit the reset button and as long as you hold it in the unit will work but if you let go of it, the unit shuts off and quits working. What could be causing this and how do we fix it. Thanks:D

Is this a ac unit or a heatpump?

This is a Heat pump I think. It does the heating and cooling with an Air Handler inside.

OK, by pushing in the contactor outside and the unit runs means you have a low volt problem, check to make sure that nothing happened to the t-stat wires going into your outdoor unit. Then check the control board outside to see if it is flashing a code