Industrial Chiller Maintenance

Chillers are essential in industrial, commercial, and laboratory applications, providing precise temperature control for processes, equipment, and cooling systems. However, even high quality industrial chillers can experience faults over time. Knowing the common chiller faults, their causes, and effective troubleshooting techniques can help operators minimize downtime, improve efficiency, and extend equipment lifespan.   Below is a practical guide for operators, maintenance teams, and facility managers on industrial chiller troubleshooting. Frequently Asked Questions on Industrial Chiller Troubleshooting Q1: My industrial chiller powers on but does not start. What could be the cause? A: This can happen due to micro-break trips, main power switch tripping, or reverse phase protection activation. To troubleshoot: Check and confirm the fault, replace or repair faulty components. Inspect the main power switch: if the line is grounded or short-circuited, repair or replace the affected parts. Verify the compressor, water pump, and motor; repair or replace if grounded. For reverse phase protection, ensure the compressor, water pump, and fan rotate in the correct direction; swap any two phases if needed. Measure the three-phase voltage with a multimeter to confirm.   Q2: Why does my industrial chiller trigger a high-pressure alarm? A: High-pressure alarms can occur due to several reasons: Dirty condenser or high ambient temperature: Keep air temperature below 40℃ and cooling water below 35℃; clean the condenser regularly. High-voltage switch fault: Press the reset switch after confirming safety. Overfilled refrigerant: Check and adjust the refrigerant charge. Cooling water pump failure or water system fault: Repair or replace the water pump.   Q3: What causes a low-pressure alarm on my industrial chiller? A: Common causes include: Insufficient refrigerant or system leaks: Inspect pipelines, repair any leaks, and refill refrigerant if necessary. Low water flow or insufficient water causing evaporator freezing: Ensure the water tank is full and valves are open; if frozen, melt ice with warm water—never hit the ice. Chilled water pump failure or pipeline blockage: Check and repair the pump and pipelines.   Q4: What triggers an overload alarm? A: Overload alarms may result from: Abnormal voltage:  Inspect and stabilize the three-phase power supply. Faulty water pump or compressor: Repair or replace. Overload relay set too low or damaged: Adjust or replace. Poor or loose line contacts: Tighten screws and ensure proper electrical connections.   Q5: Why does my industrial chiller display a water flow alarm? A: Possible reasons include: Air trapped in the water pump, preventing drainage or pump damage: Drain or replace the pump. Clogged water filter:  Clean the filter. Water shortage or damaged pipelines: Inspect and repair the system.   Q6: My industrial chiller output temperature is too low. What should I do? A: Causes may include: Water temperature setting is too low: Reset to the desired value. Water temperature probe is open or short-circuited: Inspect and replace if necessary.   Q7: The industrial chiller cooling seems weak. Why? A: This may happen if the cooling load is too small or the system refrigerant is insufficient or faulty:  Consider selecting a chiller with appropriate capacity and inspect the refrigerant system. Quick Reference: Industrial Chiller Troubleshooting Table Status / Fault Possible Causes Solutions Power ON, no startup Micro-break trip Check and confirm the fault, replace or repair Main power switch tripped 1) The power load line is grounded or short-circuited; 1) Replace new parts; 2) The compressor, water pump, or motor is grounded. 2) Repair or replace if fault is confirmed after inspection. Reverse phase protection 1) The compressor, water pump and fan are in reverse direction; 1) Swap any two phases of the power supply; 2) Phase loss. 2) Use a multimeter to measure whether the three-phase voltage is normal. High pressure alarm 1) High-voltage switch tripped. 1) Clean the condenser, keep the air temperature below 40℃/cooling water below 35℃; 2) High-voltage switch fault. 2) Press the high pressure reset switch to restart the compressor. 3) Overfilling of refrigerant. 3) Check whether the refrigerant charge is too much. 4) Cooling water pump fault or cooling water system fault. 4) Repair or replace the water pump. Low pressure alarm 1) Insufficient refrigerant or system leakage; 1) Check if the system is short of refrigerant or if there are leaks in the system pipelines, check for leaks and repair them; 2) Insufficient water flow or lack of water in the system causes the evaporator to freeze. 2) Check if the water tank is short of water and if the valve is open to the maximum. If the evaporator is frozen, drain the water and add warm water to melt the ice. Do not hit the ice with hard objects. If the copper pipe is penetrated, the compressor will be damaged! 3) Failure of the chilled water pump or pipe blockage. 3) Check the chilled water pump and pipeline system. Overload alarm 1) Abnormal voltage; 1) Check and repair the unstable voltage and missing phase of the three-phase power supply; 2) Faulty water pump or compressor; 2) Repair or replace; 3) Overload relay setting is too low or damaged; 3) Re-adjust the current value or replace; 4) Line contacts are poor or loose. 4) Re-tighten the screws. Water flow alarm 1) There is air in the water pump and it does not drain water or it is damaged; 1) Drain or replace the water pump; 2) The water system filter is clogged. 2) Clean the water filter; 3) The system is short of water or the pipeline is damaged. 3) Check and repair. Output temp too low 1) The water temperature setting value is too low; 1) Reset the temperature value; 2) The water temperature probe is open or short-circuited 2) Check the probe and replace it. Cooling weak 1) The cooling load of the unit is too small; 1) Reselect a chiller with appropriate capacity; 2) The system refrigerant is insufficient or faulty. 2) Check the system and repair it.   Note: For safety and optimal performance, industrial chiller maintenance and repairs should always be performed by qualified professionals. Regular industrial chiller inspections and preventive servicing reduce risks of faults and extend system life. For more industrial chiller maintenance methods, please refer to: How To Maintenance The Industrial Chiller   About NANJING HENGDE ELECTRICAL EQUIPMENT CO., LTD NANJING HENGDE ELECTRICAL EQUIPMENT CO., LTD is a trusted professional in the Industrial Chiller field, specializing in designing and manufacturing high-quality chillers for various industrial applications. With over 20 years of experience, Hengde provides reliable temperature control solutions, including water chillers, air chillers , mold temperature machines, and customized systems to meet the needs of factories worldwide. Their expertise ensures efficient, durable, and safe operation for all industrial cooling requirements.

As winter approaches and chillers are no longer required for continuous operation, proper shutdown preparation is crucial. This ensures that the equipment remains undamaged during the downtime and extends its lifespan, laying the foundation for smooth operation in the coming year. Hengde, as a leading manufacturer in the refrigeration industry, shares its professional advice on winter shutdown preparation for chillers.   1. Drain the Water Systems Cooling Water System First, turn off the industrial chiller’s power supply to ensure safe operation. Then, open the drainage valve of the cooling water system to drain the cooling water from the condenser, cooling tower, water pump, and associated pipes. Hengde reminds users to check the drainage flow carefully. If any blockages are present, they should be cleared immediately to ensure all water is fully drained. Residual water, if frozen during cold weather, could expand and cause cracks in pipes, condensers, and other components, leading to severe equipment damage.   Chilled Water System For the chilled water system, after turning off the power, open the drainage valve. To ensure thorough drainage, consider using the water pump to expel as much water as possible from the pipes. If the system has a filter, drain the water from the filter and clean it to prevent impurities from accumulating during the shutdown period.   2. Equipment Cleaning and Maintenance External Cleaning Use a clean cloth or brush to remove dust, dirt, and debris from the chiller’s exterior, control panel, and surrounding equipment. For stubborn stains, use a mild cleaner, but avoid harsh chemicals that could damage the surface coatings.   Internal Cleaning Open the industrial chiller’s maintenance door and clean internal components like the evaporator and condenser. Use professional cleaning tools, such as compressed air guns and soft brushes, to remove dust and debris. Pay special attention to the condenser fins to avoid damaging them, which could impair heat exchange efficiency.   Key Component Maintenance Perform a comprehensive maintenance check on critical components such as the compressor and water pump. This includes draining refrigerant, cleaning pipe dirt, drying out water in the equipment, checking the compressor’s lubrication oil, and inspecting the seals on the water pump for wear. This will help extend the chiller’s life and reduce the likelihood of failure.   3. Protective Measures Equipment Placement Avoid moving the equipment, as movement could cause damage and lead to malfunction the following year. Place the water cooled chiller or air cooled chiller in a dry, cool location to avoid damage from excessive heat, cold, or humidity.   Covering Protection Cover the entire industrial chiller with a dedicated equipment cover or waterproof tarpaulin to prevent dust, rain, and snow from entering the internal components.   Electrical Protection Inspect the electrical system to ensure all terminal connections are secure with no looseness. For exposed electrical components, wrap them with insulating tape to prevent moisture from causing short circuits. If the shutdown is extended, disconnect the main power switch and post warning labels to prevent accidental operation.   4. Inspection and Documentation Comprehensive Inspection Once the preparation steps are completed, perform a thorough inspection of the chiller. Ensure all components are properly installed, drainage is complete, and protection measures are in place.   Record Keeping Document the shutdown time, the operational status before shutdown, the tasks performed, and any issues discovered during the process. This information will be helpful when restarting the equipment the following year and serves as a valuable reference for ongoing maintenance.   5. Preparation Before Starting Next Year Equipment Inspection Before starting the chiller next year, reconnect the power supply and pipes, and inspect all components to ensure everything is in good condition.   Test Run Before full operation, conduct a test run to verify the equipment is functioning properly.   Hengde not only provides high quality chillers but also offers comprehensive technical support and after sales services. During the winter shutdown preparation, Hengde’s expert team is available to guide customers and help ensure that the process is completed correctly. This guarantees that the equipment is well protected during the winter and ready for stable operation the next time it's needed.   Choose Hengde, Choose Perfect Chillers!

A three-phase power fault is a common alarm found on industrial chillers, especially three-phase air-cooled and water-cooled chiller systems. When this alarm appears, the chiller may fail to start, the compressor may not run, or the controller may immediately stop the unit for protection.   For technicians and after-sales teams, the important point is that a three-phase power fault does not necessarily mean the chiller itself is defective. The problem may come from the factory power supply, wiring, phase sequence, protection devices, or even changes in the electrical environment around the machine. This guide explains how to troubleshoot the problem from the easiest checks to the more technical ones. What Does a Three-Phase Power Fault Mean? A three-phase chiller normally needs three-phase voltage within the specified operating range. The control system monitors the incoming power before allowing major components such as the compressor to start. If the controller detects conditions such as: Phase loss Incorrect phase sequence Overvoltage Undervoltage Large voltage imbalance Abnormal incoming power Power protection device failure the industrial chiller may display a three-phase power fault or similar alarm.   The exact alarm name varies between chiller manufacturers and controller types, so technicians should always check the electrical diagram and manual for the specific model. Common Causes of Three-Phase Power Faults 1. No or Poor Incoming Power Start with the simplest possibility. Check whether the factory power supply is actually available. Then inspect the main breaker, isolator, terminal connections and incoming cable.   A loose terminal can create intermittent contact. The chiller may work normally one day and suddenly report a power fault the next.   Solution: With the power safely isolated, inspect and tighten electrical connections according to the manufacturer's requirements. Damaged cables, plugs, breakers or terminals should be replaced rather than temporarily repaired.   2. Phase Loss A three-phase chiller can receive power on only two phases if a fuse, breaker, cable or terminal connection fails. For example, a system may measure normal voltage between two phases but show an abnormal reading on the third phase.This is why checking only one voltage measurement is not enough.   Solution: A qualified electrician should measure all three phase-to-phase voltages and compare them with the chiller's specified supply range. If one phase is missing, trace the circuit from the distribution panel to the chiller input.   3. Voltage Imbalance or Unstable Factory Power Even when all three phases are present, the voltage may not be balanced.   Large voltage differences between phases can cause excessive current and overheating in three-phase motors and compressors. Some chillers will therefore stop before the compressor starts.   Solution: Measure the three-phase voltage while the electrical system is under realistic operating conditions. If the voltage fluctuates significantly, investigate the factory power supply, transformer, distribution system, or other heavy electrical loads.   Hengde Insight：Don't check voltage only when the factory is quiet. A power supply that looks normal at 8 a.m. may behave differently when large motors, welding machines, compressors or production equipment start working. For difficult cases, monitoring the voltage during actual production can reveal problems that a single measurement misses.   4. Incorrect Phase Sequence Some three-phase chillers use a phase-sequence protection device. If the incoming phases are connected in the wrong order, the controller may prevent the compressor from starting.This can happen after electrical installation, maintenance or relocation.   Solution: A qualified electrician should verify the phase sequence with the appropriate test instrument. If it is incorrect, the wiring should be corrected only after the power has been isolated and according to the electrical diagram and local electrical requirements.   Do not randomly swap wires while the equipment is energized.   5. Faulty Phase Protection Relay The chiller itself may have normal incoming power, but the phase protection relay or monitoring device may malfunction.A damaged relay can incorrectly detect phase loss, abnormal voltage or phase sequence and prevent the machine from starting.   Solution: Measure the actual incoming voltage first. If the power is normal but the protection relay reports an abnormal condition, the relay and its wiring should be tested by qualified personnel and replaced if necessary.   6. Loose or Oxidized Electrical Terminals This problem deserves more attention than it usually gets. Industrial chillers operate for long periods under vibration and electrical load. Over time, terminal connections can become loose or develop oxidation, increasing electrical resistance.   The result may be heat buildup, unstable contact and intermittent power alarms.   Solution: Inspect the main terminals, contactors, breakers and control-circuit connections during scheduled maintenance. Look for discoloration, overheating marks or damaged insulation.   Hengde Insight：A power fault that appears “randomly” is often more interesting than a fault that appears every time the machine starts. Intermittent alarms should make technicians think about connections, heat and vibration, rather than immediately assuming that the controller has failed.   A Practical Troubleshooting Sequence For after-sales technicians, we recommend following a simple order: Power available → Main breaker → Three-phase voltage → Phase balance → Phase sequence → Terminals → Protection relay → Control transformer → Chiller controller   This prevents unnecessary replacement of expensive components.  For example, replacing a controller before checking the incoming power can solve nothing if the actual problem is a factory breaker or loose terminal. A Representative Hengde After-Sales Case A customer using a Hengde Air Cooled Chiller reported that the machine suddenly displayed a three-phase power fault and could not start. The customer initially suspected that the chiller's electrical system had failed. Hengde's technical team first asked the customer to check the incoming power rather than immediately opening the industrial chiller. The technician guided the customer through several checks. The chiller's three-phase supply was eventually found to be abnormal because of a problem with the factory-side electrical breaker.   After the breaker was repaired and the incoming power returned to normal, the alarm disappeared and the chiller restarted normally. The lesson is simple: the location of an alarm is not always the location of the problem.   For an industrial chiller, the three-phase protection circuit is monitoring the electrical conditions supplied to the machine. Therefore, the factory distribution system should always be included in the troubleshooting process. Advice for Buyers, Technicians and After-Sales Teams When purchasing a three-phase industrial chiller, buyers should confirm the required voltage, phase and frequency before placing the order.   For technicians, record the actual voltage, alarm code and operating conditions before replacing components.   For after-sales teams, ask the customer a few basic questions first: Did the fault appear suddenly or gradually? Are other machines experiencing power problems? Was there recent electrical maintenance? Was the chiller recently moved or rewired? Does the alarm disappear after restarting? Is the incoming three-phase voltage normal? These questions can significantly shorten troubleshooting time. Final Thoughts A three-phase power fault should not automatically be treated as a chiller failure. In many cases, the root cause is somewhere between the factory power supply and the chiller's electrical protection circuit.   The most efficient troubleshooting method is to work from the outside in: check the power first, then the protection devices, and only then investigate the chiller's internal electrical components.   If the cause cannot be confirmed, it is safer to stop the machine and contact the industrial chiller manufacturer or a qualified electrician rather than repeatedly restarting the equipment. This protects both the Industrial Chiller and the people working around it.