I have a customer that is popping the inline fuse on the circuit board. It is a Carrier 2.5 ton heatpump. I checked all the wires and found it would not pop the fuse if I unhooked the common going to the t-stat, so I thought it was a bad t-stat. shorted g,r,y,o with t-stat off the wall and popped fuse again. changed common wire going to t-stat and tested by shorting all out again- pop fuse. When I unhook the orange wire every thing work fine except in heat mode, So I went to the outdoor unit, reversing valve read 2.2 ohms, I thought that was low so I put straight to 28V and it just spark. Tested a new valve read 22 ohms. test new valve outside the unit,could hear clicking every time I applied power. So the old one was defiantly bad. Changed valve,test poped the fuse and smoked the t-former. When back tested valve now it is shorted! Im thinking the board must be bad and taking out the valve, right?
Is there a way to change the coil only on the valve? took me 2 hours to change it before.