If you encounter a water chiller low pressure alarm, it's important to know what to do. A low-pressure fault in a chiller is caused by excessively low compressor suction pressure. The normal suction pressure of a compressor is 0.4~0.6MPa. When the suction pressure drops below 0.2MPa, the low-pressure protection relay trips. Too low a pressure results in insufficient return air volume, insufficient cooling capacity, and unnecessary power loss.
Six possible causes of a water chiller low pressure alarm：
1. Check if the cooling water temperature is too low
This can trigger a chiller alarm due to low pressure because when the outside temperature is too low, turn on the cooling water and operate at low temperature; or if the refrigerant oil temperature is too low, the refrigerator may not be able to completely separate, causing a low-pressure fault. If the cooling water temperature is too low, turn off the cooling tower or throttle the cooling water to lower the water temperature. If the refrigerant oil temperature is too low, you can extend the chiller's preheating time to restore the normal refrigerant oil temperature.
2. Check if the evaporator is blocked
A blocked evaporator will cause poor heat exchange, preventing the refrigerant from evaporating. Therefore, regularly backflush the chiller during routine maintenance to avoid low-pressure alarms.
3. Check if the refrigerant is insufficient or leaking, as this might trigger the low pressure alarm in the chiller.
4. Check if the low-voltage protection relay is damaged
A short circuit, poor contact, or moisture damage to the low-voltage protection relay can cause communication failures and false alarms about low pressure.
5. Check the expansion valve of the chiller
If the refrigerant is sufficient, a small or clogged expansion valve can also cause low-pressure problems in screw chillers. Low-temperature operation or extended downtime of the chiller often causes this issue. Running the chiller for a while will usually restore normal operation.
6. Check the chiller system for air or water shortage
Air or water shortage in a refrigerant system causes low flow, reduced heat absorption, and wet compression, leading to low pressure difference, high temperature difference, low suction temperature, and inlet frost. To resolve, install an air vent at the high point and clean or replace clogged filters. Low pump pressure often indicates a pump-system mismatch or low compressor suction pressure (normal: 0.4–0.6 MPa). Below 0.2 MPa, protection trips, resulting in insufficient return air, inadequate cooling, and wasted power.
Welcome to inquiry about products related to walk in freezer, refrigeration unit, refrigerated Tricycle and panels.
You also can check our Tiktok, Youtube, Instagram channel for more video show.
