What is the purpose of a liquid line receiver?

This website requires certain cookies to work and uses other cookies to help you have the best experience. By visiting this website, certain cookies have already been set, which you may delete and block. By closing this message or continuing to use our site, you agree to the use of cookies. Visit our updated privacy and cookie policy to learn more.

Get Tech Tips

Subscribe to free tech tips.

Receivers, which we sometimes call “liquid receivers,” are components that store refrigerant. You'll see it on everything from small self-contained refrigeration units to very large commercial and industrial systems.

Many new techs who are used to residential air conditioning confuse receivers with accumulators. It's an understandable error, as they both contain liquid refrigerant. However, you'll find the accumulator on the suction line before the compressor; it prevents liquid from entering the compressor. On the other hand, you'll find a receiver on the liquid line after the condenser. That's because it stores liquid refrigerant that doesn't need to be in circulation for the current heat load.

The liquid receiver stores refrigerant when the system is operating at less than its maximum heat load. In general, systems with receivers are designed so that the receiver can hold the entire system's charge and still be no more than 80% full. That design allows you to pump down the entire system charge into the receiver without the danger of creating hydrostatic pressure; that refers to very high pressures resulting from full liquid expansion. (That's the same reason why we should only fill recovery tanks up to 80% full.)

The multi-position service valve at the outlet of the receiver is called a “King valve.” It can be used for refrigerant circuit access, and it may be fully front seated (turned clockwise) for pump down.

Because a receiver has both liquid and vapor present inside, many techs argue that the refrigerant cannot be “subcooled” in the receiver. The truth is that while the refrigerant that interacts between the liquid and vapor at the top of the receiver is at saturation, the refrigerant below the liquid line can be and usually will and should be subcooled.

—Bryan

Related Tech Tips

The point of this article is to give you a full understanding of the role fuses, overloads, and circuit breakers play in the protection of HVAC/R equipment. If you skim read or jump to conclusions, you will be tempted to argue. Be patient; if you want to understand, you will need to read all the […]

Read more

This tech tip was written by a friend of HVAC School, Brian Mahoney. He is an HVAC instructor at Western Suffolk BOCES/Wilson Tech. Thanks, Brian! The podcast on delta T for A/C the other day got me thinking about the formula I learned in school about calculating the GPM of a hydronic system. We will […]

Read more

All fuel-burning appliances require oxygen to burn. They require sufficient oxygen to burn clean and safe, without soot and CO (carbon monoxide). I live and work in Florida, where most of our fuel-burning appliances are 80% efficient with open combustion that utilizes air and oxygen from the space for combustion. With these low-efficiency appliances, whether […]

Read more

What is the purpose of receiver in refrigeration?

What are the two types of liquid receiver?

Why do liquid receivers have safety devices?

How do you size a liquid line receiver?