MODEL PCA090480WH
CHAPTER 2
SERVICE
Section 8: Adjustments
2-8
March
2013
Page 58
Proprietary/Confidential
© 2013 Twist, Inc.
To reduce the superheat, turn the adjusting stem
COUNTER-
CLOCKWISE
. To increase the superheat, turn the adjusting stem
CLOCKWISE
. When adjusting the valve, make no more than one half
turn of the stem at a time and observe the change in superheat closely
to prevent
over-shooting
the desired setting. As much as 30 minutes
may be required for the new balance to take place after an adjustment
is made.
The proper superheat setting is between 15°F and 20°F.
3.
Hot Gas By Pass Valve Adjustment
This procedure is more easily performed when ambient air temperature is
below 85 degrees F.
A.
Roll out the aircraft service hose and attach an airflow restriction device
to the aircraft coupler.
B.
Start the unit and after the unit has run for 20 minutes, restrict the outlet
area of the aircraft coupling.
C.
All compressor systems should be operating
D.
To adjust system one, connect the low-pressure gauge of a service
manifold to the Schrader valve on the suction line and read the
pressure. Restrict the air flow until the gauge reads 130 psig.
E.
Feel the hot gas line downstream of the hot gas valve. It should not be
hot. The valve should start to open at 130 psig. When the valve just
starts to open, the line will get cold. Adjust the valve to just open at 130
psig. At 135 psig the valve should be open and the line should be hot.
F.
The valve can be adjusted by the spring tension on top of the valve.
Adjust the airflow to get the suction pressure higher or lower to test the
hot gas valve setting.
G.
When service is complete, remove the service gauge manifold
connection and cap the Schrader valves. Replace the cap on the hot
gas valve.
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