Suction Line Accumulator

[newbietech]

I know I probably don't have enough info.,but here is the scenario: 2ton Rheem heatpump,piston metering devices, compressor(compressor was grounded according to customer) and rev. valve recently replaced by another co., running in heat mode. The system suction pressure appears normal and then compressor pitch changes,pressure drops and accumulator frosts from outlet to compressor.It stays like this for a few minutes, returns to normal and then repeats the process. Any ideas?

[stonefly]

pump the outdoor section down,disconnect power to compressor,run fan until there is no temp.change across the outdoor coil and hopefuully there is a comp. shell schrader port you can use to compare press./temp.to see if you got junk in the trunk.rule of thumb "if they didnt add a drier,they didnt evaquate"

[frigetater]

huh?????

[newbietech]

Thanks Stonefly. I went ahead and recovered the charge, changed out the dryer,pulled a good vacuum and weighed in the charge. This seems to have taken care of the problem. I'm still not exactly sure what was going on with it, so if anybody has any insight let me know.(unless your idea of insight is repling with a huhhh)

[karsthuntr]

What stonefly was trying to say was, you had non condensibles in the system.

[newbietech]

I understood that much, but i've always been told that non-codenseables get trapped in the condenser coil. How exactly would they create the problem I've described? Could it be the nons passing through the piston and temporarily dropping the pressure?