Troubleshooting techniques for chillers in the HVAC industry    

Chiller problems can be easily addressed with the below step by step air conditioning check list.  Below the troubleshooting techniques range from checking fuses to your air filters.  Under no circumstances should anyone perform these tasks unless properly trained or licensed.  

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Chiller system does not start:

1. Have all voltages and fuses checked (if system is not operating) If fuses are blown-check for shorts or grounds before new fuses are installed. There was a reason for the fuses blowing-find it first.

2. Make sure chiller has water in the closed loop reservoir tank. This can cause the flow switch to chatter or the system to ice up.

3. Check the thermostat set point and make sure the water in the closed loop reservoir is above that setting. If the water is cool the chiller may not need to run.

4. Keep all air, water filters and coils clean and clear for proper air flow.

5. Make sure any belts have been checked and spares are on hand.

6. Make sure that there is at least 1 piping line with open water circulation. This can be also obtained by the use of a water bypass at the end of the process water loop.

7. If there are water leaks: Make sure that all condensate trap lines are clear. If blocked, ceiling tiles may show water marks. If system is " Split" check the indoor evaporator section where the air filters are located, or the main unit if it is a "Package" system.

8. If a conditioned area is hot: Check all zone damper controls, thermostats or water solenoid valves, to confirm water flow through the cooling coils.

9. Safeties: Reset them 2-3 times maximum. If the system continues to trip the safety then call a chiller service technician.

Chiller-Start ups and Shut downs:

1. Do not shut off chiller by main power disconnects. Use control power switches provided on the chiller control panel.

2. First time start ups should be done by a qualified chiller service technician. Serious damage can occur if certain steps are not taken from the beginning.

3. Start ups (Daily): make sure the chiller recirculation pump is on and running before the compressors are started.

4. In some of the cases the HVAC system runs 365 days/year: If this is the case the controls for the conditioned areas (start up and shut down) are the thermostats in those particular areas. There would be no need to shut the system down where the unit is located.

5.Shutting down for several months: If this is done due to seasonal weather changes, make sure that the chilled water loop has proper chemical treatment to reduce rust and piping damage.

Operating Adjustments: (HVAC)

1. Temperature ranges: HVAC chiller systems run relatively cold 40-50F and must use freeze protection in the circulation water loop.

2. Seasonal temperature shifts (inside conditioned areas) : Even though the chiller temperature is pre-set; changes in ambient temperatures can make a conditioned area feel cooler or warmer. Adjust the zoned thermostats to combat these seasonal changes. Don't change the temperature of the chiller- a room thermostat is much easier.

3. Stagnant air or musty smells: Make sure that the indoor air filters are changed monthly or at least quarterly. Dust and dirt reduce the efficiency of the system, increase operating costs and cause poor air quality for those who work in those areas.

4. Room's) too cold or too hot: First check the zone thermostat and adjust as needed. NOTE: If the HVAC system is not a chiller but cooled by refrigeration; generally do not set the thermostat below 68-70F. The unit may ice up and cause damage to the compressor. If the system is chiller water cooled; it does not matter what the zone thermostat is set for, only the personal comfort level of those in the rooms.

Professional Refrigeration Troubleshooter

The first hands on Chiller/HVAC/R troubleshooting handbook is out in publication. This is a must have book for you and your service technicians.  It will save you time and money along with passing on the vast knowledge of 60 years experience.

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