Thursday, July 23, 2015

What am I Missing?

Yesterday found a scroll compressor locked up on Bryant RTU. Today I replaced the compressor & drier, pulled 500 micron vaccum, and added the 9# of recovered R-22. I'll note that the factory drier was about 75% restricted. Restart unit and am running 70/285# with 86 deg air entering the condenser which I split and washed 2 weeks ago - double checked cleanliness and its spotless. Can't figure out why its running such high head.

Next...pull refrigerant, change vacuum pump oil, pull another vacuum and weigh in factory charge - same results and subcooling high at 25 degrees.

Here are the facts...
86 degree OAT
76 degree RAT
70# suction, 285 - 290# head
Superheat 7-9 degrees
Subcooling 25 degrees (fixed orifice metering device)
Suction Temp 48-50 degrees
Discharge temp 205 degrees
Compressor amps & volts all 3 legs - 23.50, 206V
Cond fan spinning correct direction
No temp drop across new drier

Bryant RTU, MN#: 580FPV072115AB - -, SN#: 2102G30366
Old compressor: Carlyle MN#: SRY752AC01, SN#: S2002K09245
New compressor: Danfoss MN#: hlm075t2lc6, SN#: s2615k01668
9# R-22

The system is kind of behaving like its overcharged to me. I weighed what I took out and verified it was 9#...scale seems on. I'm assuming the high subcooling is due to the high condenser split temps. I'm kind of at a loss on what to do next. Hoping someone might have some insight. Could the factory charge on the nameplate be wrong??

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