Chiller Maintenance

Industrial chillers are widely used in industrial refrigeration equipment. Their maintenance is very important to ensure their normal operation and extend their service life. The specific maintenance measures and cycles are as follows:   Daily maintenance of the industrial chillers Wipe the outer shell of the chiller regularly to check for signs of damage, deformation or corrosion. Check whether there are blockages at the inlet and outlet of the chiller, such as dust, debris, etc. If there is a blockage, it should be cleaned in time to ensure good ventilation. Check whether the pipe connection of the chiller is firm and whether there is damage, deformation, or leakage on the appearance. Especially for pipe joints, valves and other parts, ensure good sealing. If there is a problem, the pipe should be replaced in time to prevent leakage or affect the cooling effect. Check the operating status of the chiller, such as whether the compressor, water pump and fan have noise and abnormal sounds. Check the outlet water temperature and return water temperature of the chiller to ensure that the temperature is within the set range. Check the pressure of the system, including the refrigerant pressure and water pressure, to ensure smooth water circulation.   Regular maintenance of the industrial chillers For some important parts of the chiller, special attention should be paid during maintenance: 1. Condenser of the chiller The condenser of the water cooled chiller is prone to scaling, and the condenser of the air cooled chiller is prone to dust accumulation. These two factors will not only affect the heat dissipation effect of the chiller, resulting in a decrease in cooling capacity, but will also affect the increase in the power of the chiller and easily damage the compressor of the chiller. Therefore, the condenser must be cleaned regularly, and the specific maintenance time should be determined according to the actual use environment of the customer.   2. Compressor of the chiller After the compressor of the chiller has been running for 1,000 hours, check whether the compressor refrigeration oil is normal; whether the current is normal during operation; and whether there is any abnormal sound during operation.   After the machine has been used for a certain period of time, due to various factors, the pressure switch needs to be tested to see whether it can alarm high and low pressures. For the electric control box, the dust inside should be blown clean regularly, and the screws should be checked for looseness to avoid damage to the machine.   Attached is the regular maintenance schedule for common parts of Hengde chillers Item Maintenance Period Clean the condenser 3 months Check the chilled water pump 3 months Check the wires (corner insulation)  1 month Check the cooling water supply (water-cooled) 1 week Check various safety protection devices 1 month Check the operating current of the compressor and water pump 3 months   Choose Hengde, Choose Perfect Industrial Chillers!

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.

During winter, low ambient temperatures pose several challenges for chillers. Proper usage and maintenance are essential to ensure stable operation, extend the equipment's lifespan, and reduce operational costs. Hengde, a leader in the refrigeration equipment industry, has extensive experience in the research, production, and maintenance of chillers. Below are the key points and maintenance guidelines for industrial chiller use in winter, based on Hengde’s expert advice.   1. Pre-Startup Key Checks Water System Inspection Winter temperatures can cause water to freeze, so it’s crucial to thoroughly check both the cooling and chilled water systems. Ensure the water level is normal, and that the water is clear and free from impurities. If the water quality is poor, it should be treated or replaced. Additionally, inspect the water system's filters, clean or replace the filter elements to ensure smooth water flow and prevent ice blockages in the pipes.   Insulation measures inspection Check whether the insulation layer of each component of the industrial chiller is intact, especially the pipes and water tanks. If the insulation layer is damaged, the heat loss of the equipment will accelerate in a low temperature environment, energy consumption will increase, and the water system may also freeze. If damage is found, it is necessary to repair or replace the insulation material in time.   Electrical System Pre-Inspection Quickly check the electrical wiring for visible damage and ensure that terminal connections are secure. Verify that the power supply voltage is stable and within the chiller's rated voltage range. Hengde industrial chillers are equipped with an intelligent voltage monitoring system, but a manual inspection can help identify potential issues before they arise.   2. Operating Precautions Insulation measures inspection Check whether the insulation layer of each component of the chiller is intact, especially the pipes and water tanks. If the insulation layer is damaged, the heat loss of the equipment will accelerate in a low temperature environment, energy consumption will increase, and the water system may also freeze. If damage is found, it is necessary to repair or replace the insulation material in time.   Monitor Temperature Fluctuations In winter, the lower ambient temperature reduces the cooling load on the industrial chiller. It’s essential to closely monitor the temperatures of the evaporator, condenser, as well as the outlet temperatures of industrial chilled and cooling water. Based on these readings, adjust the operational parameters accordingly to prevent prolonged low-load operation, which can reduce compressor efficiency and increase energy consumption. Hengde industrial chillers feature an intelligent control system that automatically adjusts based on temperature fluctuations, ensuring efficient operation.   Insulation measures inspection Check whether the insulation layer of each component of the industrial chiller is intact, especially the pipes and water tanks. If the insulation layer is damaged, the heat loss of the equipment will accelerate in a low temperature environment, energy consumption will increase, and the water system may also freeze. If damage is found, it is necessary to repair or replace the insulation material in time.    Prevent Ice Formation In cold weather, the risk of water system freezing is higher. To prevent freezing, add an appropriate amount of antifreeze to the water, and ensure that the water system circulates properly. If any signs of freezing are detected, immediately shut down the system, thaw it, and restart it only after ensuring the water flow is restored.   Hengde not only offers high-performance industrial chillers but also provides comprehensive technical support and after-sales services. During winter operations, Hengde’s expert technical team is available to offer remote or on-site guidance, helping users solve any issues they may encounter. Hengde also conducts regular follow-up visits to check the equipment's operation, offering targeted maintenance suggestions to ensure the industrial water cooled chiller and air cooled chiller run efficiently and reliably throughout the winter.   Choose Hengde, Choose Perfect Industrial Chillers!

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!

Industrial chillers are not silent machines, especially in large factories running 24 hours a day. But when the noise suddenly becomes louder than usual — sharp vibration, metal knocking, or heavy humming — it is often a sign that something inside the system is changing. At Hengde Chiller, we often hear new customers complain that older chillers become so noisy during summer production that even nearby offices can feel the vibration. In some centralized cooling rooms, the sound level can easily exceed 80 dB after years of continuous operation.   Many people immediately think the compressor is damaged. Sometimes that is true, but surprisingly, many noise problems actually come from installation details. A few years ago, Hengde worked on a factory cooling project where operators believed the screw chiller had serious internal failure because the entire workshop could hear low-frequency vibration during startup. After inspection, the main issue turned out to be loose piping support combined with poor vibration isolation under the chiller foundation. Once the support structure was adjusted, the noise dropped significantly.   In many factories, the building structure itself amplifies chiller vibration. The machine may not actually be extremely loud, but walls, floors, and metal pipes can make the sound feel much worse. Air-cooled chillers also develop noise problems over time. Dust buildup on condenser coils forces fans to work harder, and loose fan guards or metal panels can create rattling sounds that operators often mistake for compressor failure. We have even seen cases where a very small loose sheet metal panel produced louder noise than the compressor itself. Some of the loudest industrial chiller noises are caused by minor external vibration, not major refrigeration damage. This is why experienced technicians usually inspect structural parts before replacing expensive components.   For older chillers, lack of maintenance is another common reason noise gradually increases. After years of operation, small problems such as worn bearings, unbalanced fans, loose bolts, or aging vibration pads slowly make the system louder.   Choosing the right equipment from the beginning also matters. Compressor quality, piping layout, frame stability, and vibration control design all directly affect long-term operating sound.   Professional Noise Reduction Solutions First, install modular sound insulation covers. The fully enclosed modular structure isolates noise, with reserved vents and observation windows to ensure normal equipment operation and maintenance.  Second, optimize vibration damping: adjust equipment position to cut off vibration transmission paths, and equip professional dampers and damping pads.  Third, conduct local optimization: replace ordinary motors with low-noise explosion-proof motors and add support steel columns to suppress component vibration.  Fourth, upgrade high-specification low-noise chillers fundamentally, avoiding noise problems caused by inferior configuration and aging maintenance. Fifth, regular maintenance helps ensure stable chiller operation and longer service life. For more details, please refer to Hengde’s article: How To Maintenance The Industrial Chiller.    At Hengde Chiller, we focus not only on cooling performance, but also on stable low-noise operation for industrial environments. Through proper structural design and practical installation experience, many vibration and noise problems can be reduced before they affect factory production. Choose Hengde, Choose Perfect Industrial Chiller!

An old industrial cooling system does not always need to be completely replaced. In many factories, the real problem is that the cooling equipment has become inefficient after years of operation: compressors consume more electricity, condensers become dirty, pumps work against unnecessary resistance, and temperature control becomes less stable.   For production lines that depend on continuous cooling, upgrading the system can sometimes deliver better results than simply purchasing another oversized chiller.   This case study explains how an old industrial cooling system can be evaluated, upgraded, and optimized for lower energy consumption.   Hengde Insight：Energy saving should not start with “Which new chiller should we buy?” It should start with “Where is the existing system wasting energy?” Finding the biggest source of energy loss first usually leads to a better investment decision. The Problem: An Old Cooling System with Rising Energy Consumption The project involved a factory using chilled water for continuous production-line cooling. The original cooling system had been operating for many years.   The equipment could still provide cooling, but the operating performance had gradually deteriorated. Our technical team noticed several problems: Higher electricity consumption than expected Longer cooling time Increasing temperature fluctuations Frequent maintenance of the refrigeration system Reduced heat-transfer efficiency Pumps operating continuously at relatively high load Difficulties maintaining the required process temperature during periods of high production   Replacing the entire cooling system was considered, but the factory first wanted to understand whether the existing system could be improved.   This is an important point for technicians: an old chiller should not automatically be considered inefficient simply because of its age. Its actual operating condition should be measured before making a replacement decision. Step 1: Measure the Existing System Before upgrading anything, the technical team should record the actual operating data. Useful measurements include: Parameter What to Check Chilled water inlet temperature Actual process return temperature Chilled water outlet temperature Actual supply temperature Water flow rate Whether the system has sufficient circulation Compressor running condition Load and operating stability Condensing temperature Indicates heat-rejection performance Pump pressure Identifies unnecessary resistance Electrical consumption Establishes the energy baseline Production load Prevents comparison under different workloads   The purpose is simple: know where the electricity is going before trying to save it.   For example, if the chiller is operating at only part load while the pump and cooling equipment are running at full capacity, the refrigeration system may not be the only source of energy loss. Step 2: Check Heat Exchangers and Water Circulation One of the most overlooked problems in an old cooling system is the water circuit.   Over time, scaling, dirt, corrosion and deposits can reduce heat-transfer efficiency. Filters can become partially blocked, while old piping may create unnecessary pressure losses.   This can force pumps and refrigeration equipment to work harder than necessary.   Cleaning the heat exchanger, checking filters, inspecting valves and verifying water flow should therefore be part of the upgrade assessment.   Hengde Insight：In industrial cooling, “energy efficiency” is not only a compressor issue. A dirty heat exchanger or poorly designed water circuit can make an otherwise efficient chiller consume more electricity. Step 3: Match Cooling Capacity to the Real Production Load Another common problem is an oversized cooling system. Factories sometimes select a larger chiller because they want additional capacity for future production. However, if the system spends most of its operating time at low load, the actual energy efficiency may not be as good as expected.   A better approach is to examine the production schedule.   If the cooling load changes significantly during the day, technicians should consider: Multiple smaller refrigeration circuits Multi-compressor configurations Capacity control Variable-speed pumps where appropriate Automatic control based on actual cooling demand   The objective is not simply to install a larger industrial chiller. It is to make the cooling capacity follow the production load. Step 4: Upgrade the Cooling Equipment After evaluating the existing system, the factory decided that replacing the aging refrigeration equipment was more practical than continuing with increasingly frequent maintenance.   The upgraded solution was designed around the actual production requirements rather than simply matching the old machine's horsepower. The upgrade focused on: Higher-efficiency refrigeration components Improved heat-transfer performance More suitable chilled-water flow Better control of cooling demand Correctly sized pumps Improved protection and monitoring   For larger industrial applications, a screw chiller can be considered when the cooling load is relatively high and continuous. For smaller or variable-load applications, scroll-type systems can offer a practical alternative.   The correct choice depends on the actual load profile rather than the nameplate capacity alone. The Result: Saving Energy Through the Whole System After upgrading the cooling system, the factory achieved more stable process temperatures and reduced unnecessary operation of the cooling equipment.   The most important improvement was not simply the efficiency of the new chiller. It was the optimization of the entire cooling system.   This included the chiller, pump, heat exchanger, piping, controls and production load.   That is why energy-saving projects should be evaluated as a system rather than as a single machine.   Hengde Insight：A industrial chiller upgrade should be judged by the electricity consumed per unit of production—not only by the industrial chiller's rated efficiency. A machine that consumes slightly more power but provides much better process stability may still deliver a lower overall production cost. What Technicians Should Check Before Replacing an Old Chiller Before recommending a new industrial chiller, technicians can use this simple checklist: 1. Measure actual cooling demand Do not estimate the required capacity from the old chiller's horsepower alone.   2. Record electricity consumption Establish a baseline before the upgrade.   3. Check water flow and pressure Low flow or excessive pressure loss can reduce system efficiency.   4. Inspect heat exchangers Scaling and contamination can seriously affect heat transfer.   5. Review the operating schedule Understand whether the system operates at full load, partial load or highly variable load.   6. Check the control strategy A good control system should respond to the actual production demand.   7. Compare lifecycle cost Consider electricity, maintenance, spare parts and downtime—not only purchase price. Upgrading an old cooling system is not simply about replacing an aging industrial chiller with a new one.   The better approach is to first understand where the existing system loses energy, then redesign the cooling capacity, water circulation and control strategy around the actual production process.   For factories operating industrial cooling systems for many years, this approach can provide a practical path toward lower energy consumption, more stable production temperatures and reduced maintenance costs.   For an experienced industrial chiller manufacturer, the value is not just supplying a new machine. It is helping the technical team determine what should be replaced, what can be retained, and what should be optimized.

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.