How to Clean a Chiller Water System

Shut down the chiller so that you can inspect and clean it fully. Wipe down the coils with a damp rag to eliminate dirt.

Remove the water box covers of the smooth-bore tubes and scrub at them with a scrub brush to remove algae, mold and dirt buildup. Rinse the area with clean water once you're finished.

Scrape off at least 4 ounces of scale on the tubes with a knife if you find some. Send the sample to a water treatment laboratory. Scale is cleaned properly only once its makeup is determined; different cleaners are effective with different types of scale.

Apply a chemical cleaner to the scaled areas once you know what the scale is. A hydrochloric acid-based cleaner works most efficiently with calcium carbonate, while silicate responds well to hydrofluoric acid. Citric acid often needs to be added to hydrochloric acid to remove iron-based scale. Wear protective gear and follow all safety guidelines for each cleaner when using them; they are highly corrosive and dangerous when misused. Mix the the cleaner with water in the ratio recommended by the packaging and use a scrub brush to apply it to scale buildup.

Rinse the tubes once the scale is removed, and then scrub at them again with a heavy brush to remove any remaining scale.

Check the pressure drop at the filters in the chiller system and follow the guidelines for that particular filter model as to whether it needs cleaning or not. Different filters require different cleaning methods, so follow the instructions for your particular filters to ensure efficiency and safety.

Flush out the tubes using a high-pressure water stream if your system has that capability. Once the system is offline, a high-pressure water stream helps scrub out the inside of the tubes so buildup is removed and flushed out of the system.