Thermo King SR-2 SmartReefer2, Diagnostic Manual

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Section 5 – SR-2 Diagnostics
10 HIGH DISCHARGE PRESSURE
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Alarm Type Prevent or Shutdown Alarm
Associated Alarm
Codes Alarm Code 84 Restart Null
Component Description and Location
The high pressure cutout switch (HPCO) is located on the compressor discharge manifold.
Circuit Description
The high pressure cutout circuit is a two wire circuit. The HPCO wire connects the interface board 36 pin connector
J7 pin 17 to one side of the high pressure cutout switch. The PHPC wire connects the interface board 36 pin
connector J7 pin 18 to the other side of the high pressure cutout switch. The switch is not polarity sensitive. The
switch wires are routed in the Main Harness. The switch is connected to the sensor harness with a Deutsch
connector.
How Alarm is Set
1. Set as a Prevent alarm if the HPCO switch opens. Three attempts will be made to allow continued
operation at temporarily reduced performance. If, at the end of the three attempts full performance is not
possible, the alarm is set as a Shutdown alarm.
If continuous restarts are enabled, a shutdown alarm is not set after 3 attempts.
If restarts are disabled, the alarm will be set as a shutdown on the first occurrence.
2. Set as a Prevent alarm if the discharge pressure exceeds a pre-set value and the discharge pressure
transducer is not failed. Three attempts will be made to allow continued operation at temporarily reduced
performance. If, at the end of the three attempts full performance is not possible, the alarm is set as a
Shutdown alarm.
If continuous restarts are enabled, a shutdown alarm is not set after 3 attempts.
If restarts are disabled, the alarm will be set as a shutdown on the first occurrence.
How Alarm is Cleared
1. The alarm can be cleared manually if the condition no longer exists.
2. The alarm will clear automatically at the conclusion of a successful prevent routine.
Considerations
If the HPCO switch is open it will always shut the unit down. The switch contacts break power to the Run Relay.
Diagnostic Procedure
1. Check the refrigeration system for high discharge pressure and correct as required.
2. Check interface board fuse F1.
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02 February 2005