Common Air Cooled Screw Chiller Problems and How to Troubleshoot Them 

Air-cooled screw chillers support cooling in industries such as food processing, pharmaceuticals, plastics, and chemical manufacturing. They remove heat from process fluids and help maintain the required operating temperature. However, like other industrial equipment, they can develop faults over time. 

A drop in cooling performance, unusual noise, or a sudden alarm can affect daily operations. Finding the cause early can help prevent long shutdowns and costly repairs. A basic understanding of air cooled screw chiller troubleshooting also helps maintenance teams identify when they can check an issue and when they need a trained technician. 

This guide covers common chiller faults, their possible causes, and the steps to take when they occur. 

Why Do Air Cooled Screw Chillers Develop Problems? 

An air-cooled screw chiller works under changing heat loads and outdoor conditions. Dust, poor airflow, incorrect settings, and worn components can affect its performance. 

Some common air cooled screw chiller problems include: 

• Poor cooling or unstable water temperature 

• High discharge pressure 

• Low refrigerant pressure 

• Compressor overheating 

• Unusual noise or vibration 

• Frequent system shutdowns 

These air cooled screw chiller issues may start with small changes in performance. Regular checks can help teams spot them before they affect production. 

Common Problems and How to Fix Them 

The first step in air cooled screw chiller troubleshooting is to check the alarm display and operating readings. Do not reset the system repeatedly without finding the cause. 

1. The Chiller Is Not Cooling Properly 

An air cooled chiller not cooling as expected can affect production quality and process stability. The issue may come from poor airflow, dirty heat exchanger surfaces, or an incorrect cooling load. 

Possible causes: 

• Dust or debris blocking condenser coils 

• Condenser fans not working properly 

• Low refrigerant levels 

• Incorrect temperature settings 

• Higher process heat loads than the chiller can handle 

What to check: 

1. Inspect the condenser coils for dirt and blockage 

2. Check whether all condenser fans are running 

3. Compare the actual water temperature with the set temperature 

4. Review the current process load 

If the problem continues, ask a qualified technician to inspect the refrigerant circuit and system capacity. 

2. High Pressure Alarm 

A chiller high pressure alarm usually means the refrigerant pressure has crossed the set safety limit. In an air-cooled system, poor heat removal at the condenser is a common reason. 

 
Never bypass a pressure safety switch to keep the chiller running. It protects the equipment from unsafe operating conditions. 

3. Low Refrigerant Pressure 

A screw chiller low refrigerant pressure alarm can occur when the refrigerant pressure drops below the required level. This may affect cooling capacity and can place extra stress on the compressor. 

Common reasons include: 

• Refrigerant leakage 

• Low refrigerant charge 

• Restricted refrigerant flow 

• Faulty pressure sensors 

• Low heat load or unsuitable operating conditions 

During industrial chiller troubleshooting, technicians should check pressure readings and inspect the system for leaks. Refrigerant should not be added without identifying the reason for the pressure drop. Only trained professionals should handle refrigerant recovery, leak repair, and charging. 

4. Compressor Overheating or Failure 

Air cooled chiller compressor problems can lead to poor cooling or a complete shutdown. The compressor may overheat due to high operating pressure, poor lubrication, electrical faults, or insufficient cooling. 

Look for these warning signs: 

• Unusual humming or knocking sounds 

• Frequent compressor trips 

• High discharge temperature 

• Changes in vibration 

• Repeated overload alarms 

Stop the unit if the compressor shows signs of serious failure. A technician should inspect the electrical supply, oil condition, operating pressure, and safety controls before restarting it. 

Quick Troubleshooting Checklist for Maintenance Teams 

A simple inspection routine can make air cooled screw chiller troubleshooting easier. Maintenance teams can use this checklist during regular checks. 

• Check the control panel for active alarms 

• Inspect condenser coils for dust and dirt 

• Confirm that condenser fans are operating 

• Check chilled water inlet and outlet temperatures 

• Look for signs of oil or refrigerant leakage 

• Listen for unusual compressor noise 

• Check for loose electrical connections through a qualified technician 

• Record pressure and temperature readings 

Preventive care can reduce unexpected breakdowns. A planned air cooled screw chiller maintenance schedule also helps identify worn or dirty parts before they affect cooling performance. 

This air-cooled chiller troubleshooting guide is meant for basic observation. Internal electrical work, refrigerant handling, and compressor repairs must be left to trained technicians. 

How Regular Maintenance Helps Prevent Chiller Faults 

The exact maintenance frequency should follow the manufacturer’s instructions and the plant’s operating conditions. A professional service team can also review system performance and identify repeated faults. 

Are Air Cooled and Water Cooled Chillers Troubleshot Differently? 

Yes. Both systems remove heat from a process, but their heat rejection methods differ. 

An air-cooled unit uses fans and condenser coils to release heat into the surrounding air. A water-cooled system uses circulating water and usually needs a cooling tower or another heat rejection arrangement. 

A water-cooled scroll chiller also requires checks of its water circuit, condenser flow, and cooling tower performance, where fitted. This differs from an air-cooled screw unit, where condenser airflow and fan operation are key checks. A water cooled scroll chiller should therefore have a maintenance plan suited to its own design. 

The same principle applies when comparing an air-cooled screw chiller with a water cooled scroll chiller: always follow the specific manufacturer’s service instructions. 

Keep Your Chiller Running with Timely Checks 

Most chiller faults show warning signs before they cause a major shutdown. Changes in cooling output, pressure readings, noise, or temperature should be checked promptly. A clear maintenance plan and timely professional service can help extend equipment life and support stable production. 

When businesses need to review air cooled screw chiller troubleshooting or plan air cooled screw chiller maintenance, they should consider the equipment design, operating load, and site conditions. Refcon Chillers provides screw chiller solutions for different industrial cooling needs.