Trane CenTraVac Duplex CDHE, Operation & Maintenance Manual

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CDHF-SVU01C-EN
22
General
Information
Oil and Refrigerant Pump
Compressor Lubrication System -
A schematic diagram of the
compressor lubrication system is
illustrated in Figure 16. (This can be
applied to circuit 1 or 2.)
Oil is pumped from the oil tank (by a
pump and motor located within the
tank) through an oil pressure-
regulating valve designed to maintain
a net oil pressure of 18 to 22 psid. It
is then filtered and sent to the oil
cooler located in the economizer and
on to the bearings. From the
bearings, the oil drains back to the
manifold under the motor and then
on to the oil tank.
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WARNING
Surface Temperatures!
MAY EXCEED 150°F. Use caution
while working on certain areas of
the unit, failure to do so may result
in death or personal injury.
To ensure proper lubrication and
prevent refrigerant from condensing
in the oil tank, a 750-watt heater is
immersed in the oil tank and is used
to warm the oil while the unit is off.
When the unit starts, the oil heater is
de-energized. This heater energizes
as needed to maintain 140° to 145° F
(60-63°C) when the chiller is not
running.
When the chiller is operating, the
temperature of the oil tank is typically
115° to 160°F (46-72°C). The oil return
lines from the thrust and journal
bearings, transport oil and some seal
leakage refrigerant. The oil return
lines are routed into a manifold
under the motor. Gas flow exits the
top of the manifold and is vented to
the Evaporator.
Note: A vent line solenoid is not
needed with the refrigerant pump. Oil
exits the bottom of the manifold and
returns to the tank. Separation of the
seal leakage gas in the manifold
keeps this gas out of the tank.
A dual eductor system is used to
reclaim oil from the suction cover
and the evaporator, and deposit it
back into the oil tank. These eductors
use high pressure condenser gas to
draw the oil from the suction cover
and evaporator to the eductors and
then discharged into the oil tank. The
evaporator eductor line has a shut off
valve mounted by the evaporator and
ships closed. Open two turns if
necessary.
Liquid refrigerant is used to cool the
oil supply to both the thrust bearing
and journal bearings. On refrigerant
pump units the oil cooler is located
inside the economizer and uses
refrigerant passing from the
condenser to evaporator to cool the
oil. Oil leaves the oil cooler and
flows to both the thrust and journal
bearings.
Motor Cooling System
Compressor motors are cooled with
liquid refrigerant, see Figure 16.
The refrigerant pump is located on
the front of the oil tank (motor inside
the oil tank). The refrigerant pump
inlet is connected to the well at the
bottom of the condenser. The
connection is on the side where a
weir assures a preferential supply of
liquid. Refrigerant is delivered to the
motor via the pump. Motor
refrigerant drain lines are routed to
the condenser.