How to Troubleshoot Chiller Problems
Chiller Troubleshooting: Common Problems Even when regularly inspected and maintained, the performance of your chiller may degrade or deteriorate over time. Pumps can fail; process lines can clog; refrigerant can leak; any number of problems associated with component aging or changing environmental conditions may occur (Table I). Here are some initial steps to take to help isolate the problem:
1. Make sure that the chiller is Common Chiller Faults running. A blown circuit breaker or
fuse, loose wiring, or simply a power Most modern chillers display a fault or switch that’s been put in the ‘off’ error code when conditions affecting position may be preventing the performance are detected. These codes chiller from running. are usually fairly specific and will help you quickly diagnose problems. Some of the 2. Determine if the chiller is cooling. more common alarms and faults are: Check the temperature of the coolant at the chiller’s outlet to the process. If Low Temperature Alarm it isn’t at or near the set point The process temperature has fallen below temperature, the evaporator may be a user-set temperature value. This may be iced up or the heat transfer properties due to insufficient heat load or too high of of the coolant fluid may be a low temperature alarm setting. deteriorating. High Temperature Alarm 3. Confirm that the pump is running. A closed or partially closed valve, The process temperature has risen above failed pump, inadequate coolant a user-set temperature value. This may be volume, or process line restriction due to too high a heat load or too low of a may be preventing the adequate flow high temperature alarm setting. of liquid through the process coolant Over-Temperature Safety Alarm loop. Indicates that the process temperature 4. Check the process and has exceeded a factory- or user-set safety environmental conditions. The load cutoff. This may be due to a problem with on the chiller may be too great due to the refrigeration system or a safety setting changes in the process or the that is set at too low of a temperature. ambient temperature. Likewise, a change in the location of the chiller Low Liquid Level Alarm (near other heat generating The level of coolant in the reservoir has equipment or further from the fallen below an acceptable level. This may process equipment); loose, damaged, be due to evaporation or leaks in the or missing insulation on the piping circulation system. between the chiller and the process; or even fluctuations in line voltage may be compromising the chiller’s heat removal capabilities.
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How to Troubleshoot
Chiller Problems continued
Your best source for information on proper Low Flow Alarm maintenance and troubleshooting is the The fluid flow rate has dropped below a chiller manufacturer. Read the operating minimum factory- or user-set safety and service manuals that came with your setting. This may be due to restrictions or chiller thoroughly and adhere to blockages in the process lines or manufacturer’s recommendations. Equally equipment, a failing pump, insufficient important, make sure those manuals are coolant, or a minimum flow rate setting readily available to yourself and others The chiller’s alarm and error that is set too high. responsible for chiller operation and codes are extremely useful and maintenance. can help you quickly diagnose High Pressure Alarm problems. Table I. The process pressure has risen above a Common Chiller Problems and Possible Causes factory- or user-set safety setting. This Problem Possible Causes alarm may be due to restrictions or blockages in the process lines or Improper line voltage or loose connection equipment. The installation of a pressure bypass valve may be helpful in Chiller does Incorrect phase connection (3- phase units) applications with naturally high process not power up fluid pressures. Blown circuit breaker or fuse Power switch in ‘off’ position High Ambient Temperature Alarm Improper or fluctuating line Ambient temperature has risen above a voltage factory- or user-set safety setting. This is Insufficient fluid in reservoir usually due to changes in environmental Pinched or restricted process line conditions, such as a new location or the Closed or partially closed process installation of other heat generating No pumping or valve insufficient equipment close to the chiller. Coolant fluid unsuitable for fluid flow temperature requirements High Discharge Pressure Alarm Blocked fluid filter The refrigerant discharge pressure is too Process piping too small high. This may be due to a dirty or blocked condenser, dirty air filter, failing or failed Process restriction cooling fan, high ambient temperature, or Pump failure over-charging of the refrigerant system. Improper or fluctuating line voltage Low Discharge Pressure Alarm Clogged air filter or condenser
The refrigerant discharge pressure is too No cooling or Coolant fluid unsuitable for low. This may be caused by refrigerant insufficient temperature requirements leakage, clogging of the condenser tubing, cooling Heat transfer properties of the under-charging of the refrigerant system, coolant fluid have deteriorated or low ambient temperatures. Refrigerant leak Regular preventative maintenance and High ambient temperature knowing what to look for when the Evaporator iced up performance of your chiller deteriorates will help you optimize the uptime of both your chiller and the process it is cooling.
PolyScience ● 6600 W. Touhy ● Nile, IL 60714 ● www.polyscience.com Phone 800-229-7569 ● 847-647-0611 ● Fax 847-647-1155 ● Email [email protected]