Carrier AquaEdge 23XRV Start-Up, Operation And Maintenance Instructions Manual page 16

Oil is supplied to the compressor through two separate inlets. One
inlet leads to the suction bearings, the other leads to the discharge
bearings. Most of the oil drains back into the sump while a small
amount is used to lubricate the rotors. Rotor lubrication oil leaves
the compressor mixed with the compressed discharge refrigerant
vapor.
The oil sump contains temperature and pressure sensors and an oil
heater. (In some cases a two-stage heater is supplied, with 500 W
for the first stage and 1000 W for the second stage.) The oil sump
is vented to the compressor suction to minimize the amount of re-
frigerant absorbed by the oil. Oil Sump T is displayed on the PIC6
home screen. The oil sump pressure is used to calculate the Oil
Delta P value.
Operating Oil Delta P must be at least 18 psid (124 kPa) after the
Oil Pressure Verify Time has elapsed. Under normal full load con-
ditions, oil pressure is typically 20 to 28 psid (138 to 193 kPa). If
OIL DRAIN
VAPORIZER
SUPPLY GAS
SKIMMER LINE
VENT LINE
VAPORIZER
HEATER
VAPORIZER/OIL SUMP
DUAL STAGE
OIL HEATER
Fig. 13 — Oil Flow Schematic
sufficient oil pressure is not established or maintained the chiller
will shut down. An oil pressure delta P sensor fault will be de-
clared if the OIL DELTA P is not less than 4 psid (27.6 kPa) prior
to start-up.
If the oil pressure falls below the values specified in Table 1
during start-up, the PIC6 control will shut down the chiller.
Table 1 — Oil Pressure Requirements
TIME
(SEC)
Before Oil Pump On
After Oil Press Verify Time
During Start/Run
CONDENSER
EVAPORATOR
16
MINIMUM START-UP OIL
PRESSURE REQUIREMENT
R-134a/R-513A
PSID
< 6
18
15
OIL SUPPLY
VAPORIZER
RETURN GAS
kPa
41.4
124
103