Few days ago another tech went and checked this unit for no cool. Contactor was stuck open, he was able to bust it loose and unit worked, so replaced contactor and unit running. Today we got another call with same complaint, no cool. Space was 95* when I showed up. Check unit and same issue contactor stuck open. Other tech only had a 50 amp contactor on his truck so that's what he installed, OE is 40 amp. I changed out contactor and started unit up. Unit has not been maintained regularly so coils are packed with dirt and throw away filters are 8 lb bricks. Stabilized at 145 suction 425 discharge (R410A) 24* delta T (did not check SH). Unit pulling 22.5-22-18 amps and voltage is 194-195-192. Voltage is low but within the operating range of the unit (187-253). I pulled backing off of old contactor and the coil was black due to heat and melted plastic was keeping it from pulling in (50 amp contactor). 24v coil and transformer is putting out 25v. I did not check voltage at the coil unfortunately. Had calls stacking up behind me and had to split, what am I missing here? There's a twin to this unit about 15' away with same supply voltage and lack of maintenance but its purrin away whole time I was there.