Carrier PrimeLINE Operation And Service Manual page 73

Component Monitor Unit
Troubleshooting Alarm is display only; the alarm may clear itself during operation.
Corrective Action If alarm remains active or is repetitive, replace compressor at next available
AL18 Discharge Pressure High
Cause: Discharge pressure is over the maximum for 10 minutes within the last hour.
Component Restrictions in the refrigeration system.
Troubleshooting Ensure Liquid Line Service Valve is fully open.
Corrective Action Open Liquid Line Service Valve as needed.
Component Filter Drier
Troubleshooting Check the filter drier. If it is iced up or very cold, it indicates that the filter drier
Corrective Action Replace the filter drier if needed. See Filter Drier Service
Component Condenser Fan
Troubleshooting Check Condenser Fan for proper operation.
Corrective Action Correct as required.
Component Discharge Pressure Transducer (DPT)
Troubleshooting Confirm accurate DPT pressure readings. See Manifold Gauge Set
Corrective Action Replace DPT if defective.
Component Non-condensables in the refrigeration system.
Troubleshooting With the unit off, allow system to stabilize to ambient temperature.
Corrective Action Correct as required. See Refrigerant Charge
Component Refrigerant
Troubleshooting Check refrigerant level.
Corrective Action Correct as required. See Refrigerant Charge
AL19 Discharge Temperature High
Cause: Discharge temperature exceeds 135°C (275°F) for 10 minutes within the last hour.
Component Restrictions in the refrigeration system.
Troubleshooting Ensure the Discharge Service Valve is fully open.
Corrective Action Open the Discharge Service Valve as needed.
Troubleshooting Check the unit for air flow restrictions.
Corrective Action Clean or remove any debris from coils.
Component Non-condensables in the refrigeration system.
Troubleshooting With the unit off allow system to stabilize to ambient temperature.
Corrective Action Correct as required. See Refrigerant Charge
Component Additional Alarms such as AL16, AL24.
Table 4–5 Alarm Indications and Descriptions
opportunity.
needs replacement.
Check system pressure against Pressure Temperature Chart. See
Table 7–6.
Check system pressure against Pressure Temperature Chart. See
Table 7–6.
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Section 7.14.
Section
Table
Section 7.7.1.
Section 7.7.1.
Table
Section 7.7.1.
7.2.
7–5,
7–5,
T-362