Understanding Your Air Conditioner’s Capillary Tube

If you are like most homeowners, chances are the wealth of components inside of your air conditioner remain something of a mystery. Unfortunately, this lack of familiarity often leads to a failure to recognize and forestall common problems. While nobody expects you to acquire the detailed knowledge of an HVAC technician, a basic understanding of air conditioning components will prove highly beneficial. This article will help to improve your air conditioner knowledge by discussing the component called the capillary tube.

The Big Picture

The capillary tube plays an important role in regulating the state of the refrigerant inside of the air conditioning system. Before discussing its specific function, it may help to review the so-called refrigerant cycle as it cycles from the evaporator coil in your home to the condenser unit located outside.

Refrigerant arrives at the condenser as a high temperature, low pressure gas. In order for it to be able to absorb more heat, it must be changed back into a relatively cool liquid. The compressor acts to increase the pressure of the refrigerant, thus making it easier to convert back into a liquid. This task is accomplished by the condenser unit.

Refrigerant leaving the condenser unit is not in a high pressure liquid state. Yet its temperature remains somewhat higher than it needs to be. If it was delivered back to the evaporator unit in this state, it wouldn't be able to absorb very much heat. That's where the capillary tube comes in. By restricting the flow of the refrigerant, it helps to cool off its temperature, while also lowering its pressure.

The Capillary Tube

The capillary tube is a coiled length of copper tubing, generally located inside of your backyard condensing unit. The inner diameter of the capillary tube is very small. This fact is what allows the capillary tube to fulfill its function; by restricting the flow of refrigerant, it gives it time to cool off, while also ensuring an ideal pressure. 

Throttling Devices

The capillary tube is not alone in accomplishing its given task. It falls into a category of air conditioning components known as throttling devices. More specifically, it is what is known as a non-adjustable throttling device. This is the simplest variety of throttling devices, all of which are characterized by the fact that the flow rate of the refrigerant inside of them is not capable of being changed. For residential systems, this is just fine; commercial and industrial refrigerant systems often require more sophisticated throttling devices in order to carefully regulate the refrigerant conditions.

Contact a contractor, like Always Ready Repair, for more help.