Check Evaporator Air Flow
refrigeration
Description
In Heat mode, suction pressure stayed above 100 PSIG (6.8 bar) for more than 60 seconds, or in Cool mode SAT was 5°F (2.8°C) or more warmer than RAT for 3.5 minutes; unit shutdown and alarm.
Activation Conditions
In Heat mode, the suction pressure has been higher than 100 PSIG (6.8 bar) for more than 60 seconds OR In Cool mode, SAT is 5°F (2.8°C) or more warmer than RAT for 3.5 minutes. After the first occurrence of this alarm, the MessageCenter will display “NO TEMP CONTROL - SEE ALARM LIST”. NOTE For this alarm the unit must be running. This alarm will not occur in either the Defrost or Pretrip cycles.
Unit Behavior
Unit Shutdown and Alarm.
Reset Conditions
Auto reset in 15 minutes if Alarm 00030 Failed to Run Minimum Time is not also active or alarm may be manually reset using the display mounted keys or by turning the unit off, then back on again.
Corrective Actions
1. Check Airflow Through Evaporator Coil/Section a. Inspect coil. Ninety percent or more of the coil surface must be undamaged. Coil must be clean. b. Check airflow (with unit running). and ensure there is even airflow through the entire coil and no “dead” spots. c. Check return air bulkhead, air chute. Verify that there is good air flow, return air is not restricted and that the air chute is in good condition. d. Check that the fan clutch is fully engaged. Check upper and lower fan belt tension and condition. Verify that there is no glazing, cracking or slipping. Refer to Section 8.6. Replace if required. 2. Check System Pressures: Install manifold gauge set to check and compare actual compressor discharge and suction pressures with those shown in Unit Data. Refer to Section 8.9.10 for instruction on comparison. 3. Check Refrigerant Charge: Refer to Section 8.7.2. 4. Perform Pretrip Check: Run Pretrip and check for alarms. Any active alarms must be corrected and cleared before proceeding. 5. Check SV4: Refer to SV4 Checkout Procedure, Section 8.9.4. 6. Refer to Refrigeration Troubleshooting: Check low cooling capacity causes. Refer to Section 9.3.2 and Section 9.3.4.