MODEL PCA090480WH
CHAPTER 3
TROUBLESHOOTING
Section 4: Troubleshooting Refrigeration System
3-4
March 2013
Page 80
Proprietary/Confidential
© 2013 Twist, Inc.
Trouble X:
Refrigerant suction pressure too high
PROBABLE CAUSE
SUGGESTED REMEDY
1. Ambient
temperature above design
conditions
1. Condition could be normal. Allow
unit to operate at higher supply air
temperatures.
2. Excessive airflow caused by no
restriction on discharge hose
1.
Attach duct to aircraft, or for testing,
obstruct aircraft adapter to simulate
aircraft resistance.
3. Overfeeding of expansion valve
1.
Adjust superheat setting of
expansion valve and check to see
that remote bulb is properly attached
to suction line. (See Chapter 2-8
page 1 and Chapter 3-6 page 4.)
4. Expansion
valve
stuck
open position
1. Repair or replace valve. (See
Chapter 3-6 page 4.)
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