Oil System - Trane RTRA Series Installation Operation & Maintenance

Figure 15 - Typical CHHB compressor
Oil system operation
Overview
Oil that collects in the b
condensing pressure during compressor operation ;
therefose, oil is constantly moving to lowwer pressure
areas.
As the oil leaves the separator, it passes through the oil
cooler at the top of the condensing coils. It then goes
through the service valve and filter. At this point, some
of the oil is used to control the slide valve movement in
the compressor, via the load/unload solenoids. The
remaining oil passes through the oil master solenoid
valve and performs the functions of compressor bearing
lubrication and compressor oil injection. If the compres-
sor stops for any reason, the master solenoid valve clos-
es, isolating the oil charge in the separator and oil cooler
during «off» periods.
To ensure proper lubrication and minimize refrigerant
condensation in the compressor, a heater is mounted on
the bottom of the compressor housing. A signal from the
UCM energizes this heater during the compressor «Off»
cycle to keep refrigerant from condensing in the com-
pressor. The heater element is continiuously energized.
Oil separator
The mixture oil + refrigerant enters tangentially the oil
separator and swirls around. Thus, the oil (which is
denser) is thrown to the outside wall and flows to the
bottom of the separator. It then goes to the cooling cir-
cuit. The gas exits out the middle part of the separator
and is discharged into the condensing coils. (Figure 16).
ottom of the oil separator is at
Compressor bearing oil supply
Oil is injected into the bearing housings located at each
end of both the male and fermale rotors. Each bearing
housing is vented to compressor suction, so that oil leav-
ing the bearings returns through the compressor rotors
to the oil separator.
Compressor rotor oil supply
Oil flows through this circuit directly from the master
solenoid valve, through the oil filter to the top of the
compressor rotor housing. There, it is injected along the
top of the rotors to seal clearance spaces between the
rotors and the compressor housing and to lubricate the
rotors.
Figure 16 - Oil separator
From compressor discharge
Hot oil to oil cooler
21
To condensator
GAS
GAS
+
OIL
OIL OIL OIL