Had a call today a Trane XL12 4 ton split system from 1/2001. Dont have model or serial handy. Anyways about a month ago a tech went out and did a C&C and found run capacitor low on MFD's. Cap is a 50/7.5 440VAC. He changed it out only had a universal cap for that size. Cap work and unit ran for 3 weeks.
Another tech got called back out, cap bad again. Figured maybe fault universal cap. Replaced again with another univeral. Worked for 2 1/2 week.
I got the call today and sure enough cap was bad again. So I replaced again mean while I checked amp draw on the compressor. RLA 16.0, compressor running at 10A. Pressures were good, 10SC and 18SH TXV system. Condenser fan RLA 1.9A, fan running 1.6A.. Check voltage of each leg out of contactor 248VAC. 123VAC and 125VAC on each leg to ground.
Any idea what could be causing cap to blow? All connections tight... Thinking power issue supplying unit, customer has another unit the same and it has had zero issues. Ordered an OEM cap to try also will put it in tomorrow.
PS, Cap is a motor-mate universal