A popular metering device used on many fractional horsepower refrigeration systems is the capillary tube. One field problem frequently encountered with this type of metering device is that it can become plugged with system debris, causing a restriction. When this happens, the cap tube will typically need to be replaced.
When replacing a cap tube, the replacement must match the Btu capacity and flow characteristics of the original. It is usually easiest to obtain the replacement cap tube from the OEM to ensure the correct one is used. However, if that is not an option, a replacement cap tube from another source can be used.