Troubleshooting Chiller Low Pressure Trips: Top 4 Causes

Introduction to Chiller Safety Cutouts

When a large industrial chiller plant abruptly shuts down and displays a "Low Pressure (LP) Trip" error on its control console, production lines face immediate risk. The low-pressure switch is a vital safety shield designed to protect the compressor from operating in a vacuum or freezing the evaporator barrel.

In this field manual, we outline the Top 4 Causes of Industrial Chiller LP Trips. At Prime Cool, our mechanical engineers resolve these industrial system errors across Ranjangaon and Shirur MIDC networks daily.

The Core Failure Modes

1. Refrigerant Starvation (Leaks): A slow loss of gas drops system operating pressure below the safety threshold, triggering the cutout switch.
2. Starved Water Flow (Evaporator Side): If chilled water pumps suffer from air locking or choked inline Y-strainers, the lack of heat exchange causes refrigerant temperatures to drop, triggering a low-pressure trip.
3. Electronic Expansion Valve (EEV) Failure: A malfunctioning valve stepper motor can lock in a closed position, starving the evaporator barrel of refrigerant.
4. Fouled Internal Evaporator Tubes: Scale build-up acts as an insulator, blocking heat transfer and causing internal refrigerant pressures to drop.

Technical Recovery Protocol

Technicians must verify actual loop flow rates using differential pressure checks across the evaporator barrel before adjusting electronic cutout settings. Never jumper an LP switch to bypass a trip—doing so can freeze the water tubes, rupture the barrel, and destroy the entire machine.

Minimize factory downtime. Book an emergency industrial chiller service with Prime Cool.