System is 10-15 yr old heatpump, 10 seer. was cooling space perfectly but performance fell off, is not able to reach set point temp. . checked ducts everything is attatched, no air leaks. system pressures are 85 suction and 275 discharge.condenser fan is operating normally,proper amp draw, compressors RLA on id tag says 17.5 but is reading 11.6 while operating. evap coil was replaced by another tech. system is still operating poorly, old coil was only about 10% resticted. with that restriction it operated properly,but then it's performance fell gradually in a 4month period. the one technicians solution was to change the coil,it didn't work. Evap. fan is functioning properly, fan is wired to hi speed. return air temp. is 78 and discharge air temp. is 64, temperature drop is low, system will not satisfy. superheat is 7 and subcooling is 21. systems metering device is a fixed orifice. also compressor is a bit loud on start up. please help I'm having a bit of trouble figuring this one out.
Hi, could be compressor loosing efficiency, i think suction pressure is to high at 85, also it could be moisture in your system, did mechanic replaces filter drier on high side of system , when he replaces evap. install filter drier on liquid line, if there isn't one, also check compressor valve, you can do that by cutting or desoldering the high side from compressor, connect charging port to compressor, conect your gauge charging port, start compressor, pump up to between 150- 200 psi shut off gauge, and leave for about 1 hr. then check pressure, if pressure decreases, then your compressor valve are leaking, if it maintain same pressure, then compressor valve is o/k. you can do same on suction side, this time in vacuum, if it holds vacuum pressure, then valve is o. k, RLA(LRA) lock rotor amps, is amount of amps compressor used to start, but will drop once compressor is running, 11.6 when operating is o/k, does your evap. compatible with condensing unit?, is it right size. check also that you're using right type of freon, check condensing unit & evap labels for right type of freon, make sure they can handle same type of freon. but check compressor valve carefully, i think your comperssor could be loosing it efficiency, compressor could be your problem. good luck.good luck
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