What Issues Can Arise from A Chiller’s Low-pressure Failure?

1. Surge in Energy Usage

A chiller experiencing low-pressure failure can lead to an inefficient use of energy. When the compressor operates at low pressure, the motor load decreases, resulting in wasted energy under identical cooling conditions.

2. Diminished Cooling Efficiency

Low-pressure issues can negatively impact the cooling capacity of the chiller. Reduced suction pressure can lead to a decrease in return air volume, making it challenging for the chiller to reach its target cooling capacity. This could significantly hamper the chiller’s efficiency and performance.

What Are the Causes of Low Pressure in Chillers? How to solve it?

1. Insufficient Refrigerant or Leakage

A lack of sufficient refrigerant in the system can result in reduced suction pressure, leading to a low-pressure alarm, and ultimately, unit shutdown.

refrigerants

Solution: Potential refrigerant leaks can be identified at the junctures of components such as the compressor, condenser, filter, expansion valve, and evaporator. Once the leak is rectified, restoring the refrigerant to the appropriate level should alleviate the problem.

2. Low Ambient Temperature

If external temperatures are low, it may cause the cooling water and compressor oil temperature to drop as well. Starting the chiller under these conditions might trigger a low-pressure fault alarm. Solution: If the cooling water temperature is excessively low, either shutting off the cooling tower fan or throttling the cooling water can raise its temperature. If the compressor oil temperature is low, increasing the chiller’s preheating duration should allow the oil temperature to normalize.

3. System Pipeline Blockage

Impurities can infiltrate the system during the chiller assembly process or over time, and excessive buildup can clog the filter, restricting the refrigerant passage and return air, resulting in a low-pressure fault.

water-cooled condenser scale

Solution: Cleaning the filter, condenser, and evaporator should clear any blockages and restore the chiller’s operation.

4. Expansion Valve Opening Too Small or Damaged

The expansion valve regulates the refrigerant flow in the system. If its opening is too small, it restricts the passage of refrigerant vapor. Insufficient refrigerant steam can lower the compressor inlet pressure, leading to a low-pressure fault.

expansion valve

Solution: Increasing the opening of the expansion valve or replacing it if damaged should rectify the issue.

5. Relay Failure or Electrical System False Alarm

The relay serves as an indirect protective device. Normal compressor suction pressure ranges from 0.4 to 0.6MPa. If the suction pressure drops below 0.2MPa, it triggers the low-pressure protection relay, causing the chiller to stop running. Sometimes, moisture or circuit malfunctions can cause the low-pressure relay to work incorrectly.

Relay failure

Solution: Inspecting and repairing or replacing the low-pressure relay should address the issue. If you’re not technically savvy, reaching out to the manufacturer for assistance is recommended.

Also looking for high-pressure alarm troubleshooting? Check this.

23 thoughts on “Industrial Chiller Low Pressure Alarm Troubleshooting

  1. NANGUE RAOUL says:

    Merci pour ce que vous faites vos explications permettent même aux profanes de comprendre ce qui arrive à son unité de refroidissement.

    • szscyzl says:

      Merci, nous sommes heureux de partager ces connaissances pour aider le plus grand nombre de personnes possible.

  2. MAHENDRA says:

    DEAR SIR, I HAVE YORK AIR COOL CHILLER ESSUS LOW SUCTION PRESSURE ALARM AND LIVING AND OUT WATER TEMP- IS LOW IN 5 C AND OUT 2C SO WHAT IS ESSUS MY CHILLER PLEASE HELP ME

  3. Daniel says:

    Selamat pagi, penyebab low temperatur hold apa ya pak dan cara penanganannya bagaimana? Mohon bantuannya pak. Terima kasih

    • Gustavo says:

      Hola a todos, tengo un problema con un chiller trox con compresor marca bitzer typ CSW 9583-180 Y-400, al comenzar con una carga de 30° me tira falla, baja presión de diferencial de aceite solo lo hace al comienzo, que puede ser?

  4. Christine Albury says:

    my chiller won’t hold pressure. pump kicks in and out. when this happens pressure falls back to zero. pump is pulling too many amps and kicks out. could this be due to a faulty flow switch or bypass sensor

  5. Marco says:

    Temos um chiller grande para uma loja de 2000 m² e tem 2 maquinas de ar condicionado tambem bem grandes para toda a loja, mas o Chiller simplesmente nao liga, ja tentamos de tudo e parece que a energia não chega nele e por isso as maquinas de ar condicionado não conseguem refrigerar a loja

  6. Aminé says:

    Bonjour,
    J ai une alarme sur un groupe eau glacée MCQUAY .
    haute pression differanciel de l huile . D ou ça peu venir malgré que la haute et la basse pression sont correcte

  7. Digital thermometers NZ says:

    This troubleshooting guide for low-pressure alarms in industrial chillers is incredibly helpful. The article accurately highlights the adverse effects of low pressure, such as increased energy consumption and reduced cooling capacity. The causes of low pressure, including refrigerant leakage, low ambient temperature, pipeline blockage, and faulty expansion valves, are well-explained. The provided solutions offer practical steps to address each issue effectively. This comprehensive guide is a valuable resource for chiller maintenance and troubleshooting.

    • Paulo melo says:

      Alarme de alta pressão não para e não resfria.se por gentileza puder me ajudar agradeço.

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