Carrier 19XL - Manual (Page 45)

of post-lubrication. The oil pump can also be energized for testing purposes in the Control Test.
Ramp loading can slow the rate of guide vane opening to minimize oil foaming at start-up. If
the guide vanes open quickly, the sudden drop in suction pressure can cause any refrigerant in
the oil to flash. The resulting oil foam cannot be pumped efficiently, therefore oil pressure falls
off and lubrication is poor. If oil pressure falls below 15 psid (103 kPad) differential, the PIC will
shut down the compressor.
Oil Reclaim System
The oil reclaim system operates to return oil back to the oil reservoir by recovering it from 2
areas on the machine. The primary area of recovery is from the guide vane housing. Oil also is
recovered, along with refrigerant, from the cooler.
Any refrigerant that enters the oil reservoir/transmission area is flashed into gas. The
demister line at the top of the casing will vent this refrigerant into the suction of the compressor.
Oil entrained in the refrigerant is eliminated by the demister filter.
During Normal Machine Operation , oil is entrained with the refrigerant. As the
compressor pulls the refrigerant into the guide vane housing to be compressed, the oil will
normally drop out at this point and fall to the bottom of the housing where it accumulates. Using
Click here for Figure 4 — Lubrication System