Common Causes Of The Compressor-Destroying Liquid Slugging Problem

Posted on: 18 July 2016


The air conditioning process is dependent on the ability of the air conditioning system to convert liquid refrigerant to a gas and then back to a liquid. To cool air, the liquid refrigerant absorbs heat from the passing air. This usually causes it to evaporate. But since the system needs to reuse this refrigerant, the system has to convert it back into a liquid. Part of the conversion process involves compressing the refrigerant gas and this is what a compressor does.

However, a problem usually arises when liquid refrigerant finds its way into the compressor. This is because parts of the compressor are designed to specifically deal with a gas. The presence of a liquid in this area is therefore something that they are not prepared to handle. As a result, parts of the compressor such as the piston, rotary vane pump and scroll spirals may end up getting damaged. This is what liquid slugging can do to your system. Here is what you should know about how this problem can arise.

Refrigerant overcharge

Under normal operations, the heat of the air passing over the evaporator coil is usually enough to convert all of the liquid refrigerant that is available in the evaporator coil into a gas.

However, when there is too much of the refrigerant in the system, this heat is likely not to be enough to cause all the refrigerant to turn into a gas. As a result, some of the refrigerant may then enter into the air conditioner's compressor while still in liquid form, something that may then cause extensive compressor damage.

Malfunctioning thermostatic expansion valve

The thermostatic expansion valve acts as a gatekeeper. It is tasked with the role of ensuring that only a given amount of liquid refrigerant finds its way into the evaporator coil. This is important as it ensures that the evaporator coil area is only fed with as much refrigerant as is necessary to cause cooling. This also helps to maintain the low-pressure-area quality of the evaporator coil.

However, if your system has a defective thermostatic expansion valve, it may allow an excessive amount of liquid refrigerant to enter into the evaporator coil area. This is a problem since the warm air passing over the evaporator coil at any given time is limited. As a result, the heat available in the area will not be enough to convert all of the liquid refrigerant into a gas. Some of this liquid will then find its way into the compressor and hence causing liquid slugging problems.

Liquid slugging is a serious condition that not only reduces the efficiency of an air conditioning system, but also leads to extensive compressor damage. Replacing the malfunctioning thermostatic expansion valve and having a HVAC contractor empty and then recharge your air conditioning system is an easy way to avoid slugging-related costs. Contact a business, such as Biggerstaff Plumbing Heating & Air, for more information.