Chiller Fault — High Head Pressure

What This Fault Means

A high head pressure fault means the condenser-side refrigerant pressure exceeded the high-pressure cutout setting. The compressor shuts down to prevent mechanical damage and excessive power consumption.

Common Causes

• Dirty condenser coils (air-cooled) or fouled tubes (water-cooled)
• Condenser fan failure or reduced airflow
• Cooling tower water temperature too high
• Refrigerant overcharge
• Non-condensable gases (air) in the refrigerant circuit

Recommended Fix

1. Clean the condenser coils with a coil cleaner and low-pressure water (air-cooled).
2. Verify all condenser fans are running and rotating in the correct direction.
3. For water-cooled, check the cooling tower performance and condenser water flow rate.
4. Check the refrigerant charge level — if overcharged, recover excess to a cylinder.
5. If subcooling is low and head pressure is high, suspect non-condensables — purge the system.