R410a with TXV - After a 4" spacer was installed between my evaporator and furnace, the tech added a little 410a, but I suspect he overcharged. Subcooling is about 17F (nameplate calls for 15F, so its within 3F).
But when I had another tech do a compressor pumpdown test for me, the following happens:
suction pressure starts to drop, hi side pressure starts to drop, but the high pressure trips the unit offline rather quickly (suction only gets down to 150, high side gets down to 200).
I assume that high pressure sensor is on the other side of the king valve, so I guess we aren't really seeing the pressure between the compressor discharge and the king valve.
Is this a symptom of over-charge? It does not trip during normal operations.
I've got another company coming out next week to do a full check of this system, but I wanted to check my logic.