Causes And Solutions of High Pressure Failures of Chillers

High-pressure failures in chillers can lead to significant operational disruptions and increased maintenance costs. According to various sources, common causes of these failures include excessive refrigerant charge, insufficient cooling water flow, and blockages in the condenser. Understanding these causes is crucial for effectively addressing and mitigating high-pressure issues in chiller systems.

1. Excess Refrigerant Charge

This is often observed after maintenance work and is characterized by elevated intake and exhaust pressures alongside high running current of the compressor.

Solution: Discharge the excess refrigerant by assessing the suction and discharge pressures, equilibrium pressure, and running current until they return to normal levels.

2. High Cooling Water Temperature And Poor Condensation

The optimal cooling water temperature for chillers operates best between 30°C and 35°C. Higher water temperatures can severely impair condensation efficiency. This issue tends to be prevalent during warmer months.

Solution: Identify reasons for the high water temperature, possibly due to cooling tower malfunctions like fan failure or low water levels. Increasing water storage capacity can alleviate high water temperatures.

3. Insufficient Cooling Water Flow

This situation generally manifests as reduced pressure differences between the inlet and outlet of the unit, thereby increasing temperature discrepancies.

Solution: Clogged or undersized pipeline filters can restrict water flow. To resolve this, select appropriate filters and ensure regular cleaning to maintain free water flow.

4. Fouled or Blocked Condenser

Condenser fouling is common when using tap water, especially at temperatures above 30°C. Exposure to environmental debris can also lead to increased scaling and decreased heat exchange efficiency.

Solution: Regular backwashing of the unit and chemical cleaning as necessary will help maintain condenser performance and mitigate fouling.

5. False Alarms From Electrical Malfunctions

Worn or wet high-pressure protection relays, or damaged electronic boards, can generate false alarms leading to unnecessary system shutdowns.

Solution: In cases of alarm without the corresponding pressure issues, check connections and reset relays as needed to verify normal compressor operation.

6. Presence of Non-condensable Gases

Air in the refrigeration system can cause erratic readings on high-pressure gauges, often stemming from incomplete evacuation after maintenance.

Solution: After experiencing symptoms of non-condensables, the system should be evacuated or re-evacuated to remove contaminants and restore optimal refrigerant conditions.

By addressing these identified causes and implementing the suggested solutions, operators can enhance the reliability and efficiency of chiller systems, ensuring longevity and performance. Regular maintenance and monitoring play critical roles in preventing high-pressure failures in chillers.