How to Use and Maintain Your Recirculating Chiller

By Aimee O'Driscoll, 17 July 2018

Proper use and maintenance of your recirculating chiller can help ensure the machine keeps running efficiently and limit the need for downtime. Improper maintenance could lead to your chiller not being able to maintain temperature, rendering it useless for certain applications. Using and maintaining your chiller correctly can increase the lifespan of the machine and save you time and money on finding a replacement.

In this post, we’ll explain the steps you can take to ensure your chiller lasts as long as possible. We’ll go into these in more detail below, but some of the things you can do are:

  1. Ensure the environment is the right temperature and humidity
  2. Flush or top off the coolant
  3. Clean the condenser fins
  4. Lubricate the pump
  5. Clean or replace the strainer
  6. Clean or replace the filter

The frequency with which you need to complete maintenance tasks will depend on various factors. These include how often the chiller is used, the environment it’s situated in, and the type of coolant used in the system.

Let’s take a look at the above actions in a bit more detail.

1. Ensure the Environment is the Right Temperature and Humidity

If the ambient temperature is outside of the optimal range (roughly 13 - 35°C), it could place a strain on electrical components or cause the evaporator to freeze and burst. Low ambient temperature (within the optimal range) can have a positive impact and boost efficiency. However, higher temperatures will result in less efficient heat transfer, a higher condensing pressure, and a reduction in overall system performance.

High humidity (above 80%) could cause condensation to form which, in turn, can damage electrical components.

2. Flush or Top Off the Coolant

Running the machine with too little coolant could cause permanent damage to the pump. The level of coolant in the machine should be checked on a regular basis, about once per week as a rough guide. If needed, the coolant should be topped off.

If the level has dropped significantly over a short period, you may have a leak. External leaks will be easy to spot as there will be coolant on the floor and possibly dripping from the chiller. Internal leaks might be more difficult to diagnose, but a drastic drop in coolant level means some investigation should be carried out.

The coolant should be flushed and replaced on at least a quarterly basis, or more regularly for some machines. The frequency with which you need to flush will depend on the coolant you use. For example, water will enable things like algae to grow readily, and depending on your water quality, you may get a buildup of mineral deposits. When cleaning, using a special bath cleaner such as PolyClean can help reduce the frequency with which you need to clean your bath, without negative consequences.

Additionally, if you’re using water as your coolant, adding a corrosion inhibitor, such as ethylene glycol, can help prevent corrosion of passages within the machine. Also, using an algae inhibitor will prevent algae growth and limit the need to flush the coolant more frequently.

3. Clean the Condenser Coil Fins

It’s a good idea to keep the chiller in as clean an environment possible. However, even if you're diligent with cleaning, dust and dirt from the environment can build up on the condenser coil fins. This can inhibit air flow and lower the cooling capacity of the machine.

The fins should be checked regularly, even on a weekly basis in a more dust-prone environment. To clean the fins, you can use a fin comb, a paint brush, a vacuum cleaner, or compressed air.

4. Lubricate the Pump

Depending on the type of pump your recirculating chiller is fitted with, it may require periodic lubrication. If it runs dry for even a short time, it could be permanently damaged. If your chiller is used continuously, then the pump will likely need to be oiled at least once every six months to one year.

You can consult your manufacturer's instructions for more details about frequency and for advice about how to lubricate the pump, including how much and which type of oil to use.

5. Clean or Replace the Strainer

Also depending on the type of pump, there may be a strainer that needs to be inspected and cleaned on a regular basis. If there’s buildup on the strainer, this will decrease the flow rate. In turn, the pump will need to work harder and will wear more quickly.

Again, this will be model-dependent, so it’s best to consult your manufacturer’s instructions to find out more.

6. Clean or Replace the Water Filter

If your chiller comes with a water filter, it’s wise to check the filter regularly, roughly once a month. It is especially prone to buildup in the initial period after installation. This can impact performance in a surprisingly short period of time. In fact, it’s recommended that you check the filter the day after installation for any buildup.


Not taking proper care of your chiller will lead to a machine that doesn’t work efficiently and may not be able to maintain temperature. By following the steps in this post, you’ll have a properly working machine that hopefully lasts for a long time.