Foam in Comp Oil Sight Glass

[jwasir]

Does the foam in oil SG means liquid coming back to comp??

I've seen a system where Super heat was 25 deg and still glass was foaming badly.

Any Suggestions??

[gregd1401]

May be caused by low suction pressure due to insufficient refrigerant.

[sedgy]

jwasir, have you got a cch, < crank case heater < on the compressor?

[chemi-cool]

The foam is boiling refrigerant.
Check that the oil level sight glass is over 38°C and it should be OK, a little bit of refrigerant in the oil never killed any compressor.

[Tesla]

Some systems like Carrier Recip chillers keep the liquid solenoid closed for 30 seconds at start up to boil off any refrigerant in crank case. There could also be a partially blocked suction service valve strainer causing the same.

[SkyWalker]

Check that the oil level sight glass is over 38°C and it should be OK,

hi chemi-cool, is this a good rule of thumb for all refrigerant oils?

if so, what is key about 38C and over?