Ingersoll-Rand Thermo King CRR DF MPC2000, Maintenance Manual

Page: 93 / 165

Microprocessor Controller
92
19 Temperature Too Far from Setpoint
(Check Alarm)
• After 80 minutes of operation, return air
temperature is not in-range and does not
approach setpoint by 0.1 C/hr.
• Indicates:
• Ice or frost on evaporator coil
• Low refrigerant charge
• Container air leakage (doors open)
• Press SUP/RET key to check supply and return
air sensor temperatures. Compare
temperatures to evaluate unit cooling capacity
and performance. Temperature difference
should be 4 C to 6 C.
• Open evaporator door. Inspect coil for ice or
frost and initiate manual defrost if necessary.
• Check refrigerant charge of R-23 and R-134a
systems.
NOTE: This alarm can be activated if the
supply or temperature does approach
setpoint.
20 Defrost Time Too Long
(Check Alarm)
• Heat signal has been on for more than 90
minutes (120 minutes if power supply below 55
Hz) during Defrost.
• Indicates:
• Defective heater elements
• Defective heat relay
• Evaporator sensor placed wrong
• Initiate a manual defrost and check amperage
draw and evaporator coil temperature. Evaluate
defrost performance.
• Open evaporator door and check location of
evaporator coil sensor.
NOTE: This alarm can be activated at low
voltage and very low box temperature
conditions, even under normal operating
conditions.
22 Capacity Test 1 Error
(Check Alarm)
• Occurs during pre-trip (PTI) test only.
• Return air temperature does not reach -30 C (22
F) within 4 hours.
• Indicates:
• Incorrect refrigeration system operation
• Container door is open
• Container is not empty
• Incorrect connection of return air sensor
• Open evaporator door and inspect evaporator
fan rotation. Make sure fans are rotating
correctly on low speed.
• Operate unit on Cool and check discharge and
suction pressure gauge readings on both the
R-23 and R-134a refrigeration systems. Check
the refrigerant charge of the R-23 and R-134a
systems.
• Check the return sensor connections.
23 Capacity Test 2 Error
(Check Alarm)
• Occurs during pre-trip (PTI) test only.
• Return air temperature does not reach -55 C
(-67 F) within 6 hours.
• Indicates:
• Incorrect refrigeration system operation
• Container door is open
• Container is not empty
• Incorrect connection of return air sensor
• Open evaporator door and inspect evaporator
fan rotation. Make sure fans are rotating
correctly on low speed.
• Operate unit on Cool and check discharge and
suction pressure gauge readings on both the
R-23 and R-134a refrigeration systems. Check
the refrigerant charge of the R-23 and R-134a
systems.
• Check the return sensor connections.
Code Description Corrective Action