Cooling Troubleshooting |
| If alarms conditions are corrected and cleared, operation of the | |
Use the Scrolling Marquee display or a CCN device to view the | compressors and fans may be verified by using the Service Test | ||
mode. (See Table 4.) See Table 14 for general cooling service | |||
cooling status display and the cooling diagnostic display (see | |||
analysis. | |||
Appendix A) for information on the cooling operation. Check the | |||
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current alarms and alarm history for any cooling alarm codes and |
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correct any causes. (See Table 12.) Verify | any unique control |
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configurations per installed site requirements or accessories.
Table 14 – Cooling Service Analysis
PROBLEM | CAUSE | REMEDY |
Compressor and Fan Will Not | Power failure. | Call power company. |
Start. | Fuse blown or circuit breaker tripped. Check CB1, | Replace fuse or reset circuit breaker. |
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| CB2, and CB3. |
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| Disconnect off. | Power disconnect. |
| Compressor time guard to prevent short cycling. | Check using ComfortLink Scrolling Marquee. |
| Thermostat or occupancy schedule set point not | Check using ComfortLink Scrolling Marquee. |
| calling for Cooling. |
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Compressor Cycles (other than normally satisfying thermostat).
Compressor Operates
Continuously.
Excessive Condenser Pressures.
Condenser Fans Not Operating. Excessive Suction Pressure.
Suction Pressure Too Low.
Outdoor temperature too low.
Active alarm.
Insufficient line voltage.
Active alarm.
Unit undersized for load.
Thermostat or occupancy schedule set point too low. Dirty air filters.
Low refrigerant charge.
Condenser coil dirty or restricted.
Loose condenser thermistors.
Dirty condenser coil.
Refrigerant overcharge.
Faulty TXV.
Condenser air restricted or air short cycling. Restriction in liquid tube.
No Power to contactors. High heat load.
Faulty TXV.
Refrigerant overcharged.
Dirty air filters.
Low refrigerant charge.
Check Compressor Lockout Temperature using ComfortLink Scrolling Marquee.
Check active alarms using ComfortLink Scrolling Marquee.
Determine cause and correct.
Check active alarms using ComfortLink Scrolling Marquee.
Decrease load or increase size of unit. Reset thermostat or schedule set point. Replace filters.
Check pressure, locate leak, repair, evacuate, and recharge.
Clean coil or remove restriction. Tighten thermistors.
Clean coil.
Recover excess refrigerant.
1. Check TXV bulb mounting and secure tightly to suction line and insulate.
2. Replace TXV (and filter drier) if stuck open or closed.
Determine cause and correct. Remove restriction.
Fuse blown or plug at motor loose. Check for sources and eliminate
1. Check TXV bulb mounting and secure tightly to suction line and insulate.
2. Replace TXV (and filter drier) if stuck open or closed.
Recover excess refrigerant. Replace air filters.
Check pressure, locate leak, repair, evacuate, and recharge.
48/50PG and PM
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| Faulty TXV. | 1. Check TXV bulb mounting and secure tightly to |
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| suction line and insulate. |
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| 2. Replace TXV (and filter drier) if stuck open or |
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| closed. |
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| Insufficient evaporator airflow. | Check belt tension. Check for other restrictions. |
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| Temperature too low in conditioned area (low | Reset thermostat or occupancy schedule. |
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| return‐air temperature). |
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LEGEND |
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CB | - | Circuit Breaker |
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TXV | - | Thermostatic Expansion Valve |
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