What’s A Refrigeration Cap Tube & Why Do They Fail?

A Refrigeration Cap Tube also called Refrigeration Capillary Tubing is a device used to meter refrigerant from a liquid state to a gas state. This is the process that removes heat from a cooler or freezer.

Capillary Tubing is used in almost all smaller refrigeration units in restaurants & bars. It is used for medium & low temperature applications. A Cap Tube is basically a copper pipe usually around 6 feet in length or so & the same size & shape as 1 strand of Spaghetti. It resembles a 6 foot long copper strand of Spaghetti! Throughout the entire length is an extremely small hole through which refrigerant flows. The capillary tubing runs from the outlet of condenser coil by compressor into the evaporator coil inside a cooler or freezer. Capillary Tubing can be problematic & does have a tendency to restrict causing a failure of refrigeration. It is the most popular metering device used widely by most manufacturers. This is simply because it is the cheapest metering device. Restrictions in the capillary tube are usually caused by lack of proper maintenance. When systems overheat the oil within refrigerant piping becomes overheated & damaged. The burnt oil causes the blockage of pipe which causes system to fail. When cap tubes become blocked it puts a massive strain on the compressor. This can lead to a compressor going bad.

The easiest way to prevent cap tube restrictions is to have a proper maintenance plan. Keeping a units condenser coil clean will go a long way towards preventing system restrictions & failures. An end user should inspect & clean the condenser coil every four to six weeks. This is the coil on the exterior of a cooler or freezer & is usually located close to compressor. A brush can be used to clean condenser coil. A professional maintenance service from a refrigeration company should be considered at least once or twice a year. A service company will use chemicals to better clean condenser coils on commercial refrigeration. See links below for additional information on DIY maintenance & more. Please contact us with any questions.

DIY Commercial Refrigeration Maintenance Inspection

Commercial Refrigeration “Service” vs. “Maintenance” – There’s a difference

Routine Refrigeration Maintenance A Case Study

Article written by Chicago’s Leading Refrigeration Repair Expert Mitch Byrne