13-21-615 v01 Page 64
Compressor, air/oil reservoir, separation chamber and all piping and tubing may
be at high temperature during and after operation.
COMPRESSOR OIL COOLER - RADIATOR TYPE
(Figure 1-5, page 10) The oil cooler motor and fan is
mounted on the oil cooler module; air is exhausted through the oil cooler and away from the unit. Do not
obstruct air flow to and from the oil cooler. Allow a minimum of three (3) feet clearance around the cooler.
Keep both faces of cooler core clean for efficient cooling of compressor oil.
Figure 5-9 THERMOSTATIC MIXING VALVE ELEMENT
THERMAL CONTROL (THERMOSTATIC MIXING) VALVE
(Figure 5-9) is installed in system as shown in
Figure 5-3, page 54. This valve is used to control temperature of the oil in both air-cooled radiator and
water-cooled heat exchanger type oil cooler systems. On start-up with unit cold, element is open to bypass,
allowing oil to pass directly from the reservoir to compressor during warm-up. As oil warms, element
gradually closes to the bypass allowing more of the oil from the cooler to mix with oil from the bypass.
After the unit is warmed up, the mixing valve maintains oil injection temperature into the compressor at a
minimum of 130
F (55
C) or 160
F (71
C) depending on the air end. This system provides proper
compressor warm-up and helps prevent moisture contamination of oil.
To check element, heat in oil, it should be fully extended at 130
F (55
C) or 160
F (71
C) depending on
the thermal mixing valve installed in the air end. If unit shuts down due to high air discharge temperature,
it may be that one or both thermostatic mixing valve elements (Figure 5-3, page 54) are stuck open.
Remove mixing valve and clean all parts thoroughly when flushing the oil system.
COMPRESSOR OIL COOLER - WATER-COOLED HEAT EXCHANGER
(Figure 5-3, page 54) The heat
exchanger oil cooler is a multiple pass type, with water in the tubes and oil in the shell. The oil temperature
is controlled by the thermal (thermostatic mixing) valve. The optional water control valve may be used to
conserve water.
