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Seven Common Problems with Water Chillers

water chiller

1.Small Temperature Difference Between Inlet and Outlet Water

When users find that their chiller’s inlet water temperature is 24℃ and the outlet water temperature is 23℃, resulting in a small temperature difference that doesn’t meet their needs, the following reasons might be the cause:

  • The chiller’s output cooling capacity is low, possibly due to faults or partial loading issues. Check the operating current of the water industrial chiller to diagnose this.
  • Poor heat transfer, possibly due to scaling on the heat transfer tube. This can be assessed by checking the temperature difference between the water temperature and the evaporation temperature.
  • Excessive water flow, which can be identified by observing the inlet and outlet water pressure difference of the evaporator and the water pump’s operating current.
  • Inaccurate sensor or temperature meter readings after ruling out the above issues.
water cooler chiller

2.Chiller Fan Noise

Noise from the air cooled chiller fan can be annoying and contribute to environmental pollution. The reasons include:

  • Friction or impact with air when the blades rotate, which generates noise at multiple frequencies related to the fan speed. Using different numbers of blades for the moving and static wings can help reduce noise resonance.
  • Vortex formation on the back of the fan blades decreases efficiency and generates noise. This can be mitigated by ensuring a smooth and moderate installation angle of the blades.
  • Resonance with the air duct shell, which can be minimized by keeping the air duct and fan shell joints smooth and covering the air duct with soundproof materials if needed.
  • Additional noise sources may include bearing issues due to poor precision, improper assembly, or poor maintenance.

3.Communication Failure

Water cooling chiller are controlled through communication lines and a main interface board. Communication failure often results from poor contact or disconnection of the communication line, especially due to moisture and oxidation. Other causes can include:

  • Unit electronic board or main interface board failures.
  • Incorrect address dial switch selection.
  • Power failure.
water cooling chiller

4.Low Pressure Failure

When the compressor suction pressure is too low, it triggers the low-pressure protection relay. The normal suction pressure should be 0.4-0.6MPa, with a protection value set at 0.2MPa. Low suction pressure can indicate insufficient return air volume, poor cooling capacity, and wasted energy. It may also lead to poor heat dissipation and potential motor damage. Causes include:

  • Insufficient or leaking refrigerant.
  • Inadequate refrigerant water flow.
  • Evaporator blockage or poor heat exchange.
  • Electrical failure leading to false alarms.
  • Low external temperatures.

5.High Pressure Failure

Excessively high compressor exhaust pressure activates the high-pressure protection relay. The normal condensing pressure should be 1.4-1.6MPa, with a protection value of 2.0MPa. Prolonged high pressure can cause excessive current, risking motor burn-out and compressor exhaust valve damage. Causes include:

  1. High cooling water temperature or poor condensation.
  2. Needs to be more cooling water flow.
  3. Condenser scaling or blockage.
  4. Excessive refrigerant filling.
  5. Non-condensable gases like air and nitrogen in the refrigerant.
  6. Electrical failures causing false alarms.
water industrial chiller

6.Compressor Overheating

The compressor motor winding has a thermistor with a typical resistance of 1kΩ. When the winding overheats and the resistance exceeds 141kΩ, the thermal protection module activates, shutting off the unit and lighting the overheating fault indicator. Causes include:

  1. Excessive compressor load causing overcurrent operation.
  2. Electrical failures causing overcurrent operation.
  3. Damp or damaged overheating protection module, damaged intermediate relay, or poor contact.

7.Low Valve Temperature Failure

The expansion valve outlet temperature, which affects heat exchange, is usually 5-6℃ different from the refrigerant water outlet temperature. When a low valve temperature failure occurs, the compressor stops but resumes operation once the temperature rises above -2℃. Causes include:

  1. Minor refrigerant leaks.
  2. Blocked or inadequately opened expansion valve.
  3. Insufficient refrigerant water flow or evaporator blockage.
  4. Electrical failures causing false alarms.