Airedale downflow A/C

[damo567]

I have a problem on an Airedale downflow package unit running on 407c. I have recovered the gas changed the drier and sightglass, pressure tested vacuumed down etc etc. Recharged with the recommended weight of gas.

When the unit is running it has a clear sightglass but every minute or so the sightglass has bubbles in it which lasts about 20 seconds then it goes clear again. The superheat is all over the place ranging from no superheat to 8K. (when the bubbles start the superheat drops right off to nothing).

When I removed a hose from a port located at the bottom of pipe work prior to the compressor suction (it's like a u bend) I noticed there was a lot of oil, could there be oil sat in the compressor suction pipe work causing this erratic running or is it a problem with the TXV?

Cheers

[NoNickName]

The problem is with the condensing control. It is probably hunting. Try stabilize the condensing pressure and try again.