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How to Spot a Bad AC Accumulator or Receiver-Drier

Stephen Fogel
June 8, 2018

ac accumulator receiver-drier

Symptoms of a bad accumulator or receiver-drier

Unless you are experienced in working on your AC, we suggest that you leave any repairs to your mechanic. This system operates under high pressure and has many moving parts, so troubleshooting can be a complex process.

1. You hear rattling sounds when the AC is on: This can indicate that there are loose or damaged parts inside your accumulator or receiver-drier. If the part seems fine, other causes could be a loose hose or fitting, or a bad compressor.

2. You notice refrigerant leaks under the car or hood: This can be caused by a malfunctioning accumulator or receiver-drier, which is allowing pressurized refrigerant to escape. Leaks can also come from other areas of your AC system.

3. Your AC isn’t blowing as cold as it should: Either of these parts can become clogged, preventing that refreshing cold air from coming out of your vents.

» LEARN MORE: Get an estimate for your AC system diagnosis

How to deal with a bad accumulator or receiver-drier

Because the accumulator or receiver-drier acts as the moisture and particulate filter for your car’s AC, the best solution for most problems is simply to replace it. It’s an inexpensive part, and replacing it is good for the long-term health of your AC system. 

Also keep in mind that once you open one of these components and expose it to the outside air, you have destroyed any remaining moisture-absorbing qualities it may have. 

This part should also be replaced any time you need a new AC compressor, or have other major work done on the system.

Get it diagnosed by a professional
 

How the accumulator works

Your car’s air conditioning system has either an accumulator or a receiver-drier. These are two different parts that perform the same function: to remove any liquid from your refrigerant before it goes through the compressor. 

As your refrigerant moves through your air conditioning (AC) system, it can pick up water, and typically takes on at least a partly liquid form at some point. But water will react with refrigerant to form hydrofluoric and hydrochloric acids, which will cause internal corrosion. The formation of ice crystals in the lines can also result in blockages and stop the cooling process.

Also, the refrigerant must be in a fully gaseous form when it travels back through the system to the compressor. To keep moisture from causing problems, your vehicle’s air conditioning system has either an accumulator or a receiver-drier. It will only have one, not the other, and they’re not interchangeable.

If your vehicle’s AC system has an accumulator, it is likely to be the last component the refrigerant passes through before it enters the compressor. The accumulator is a metal canister with two fittings for the refrigerant to be piped in and out. 

As the partly gaseous/partly liquid refrigerant enters the accumulator at the top, it passes through a U-shaped tube that is cut off on top of the far side of the “U.” As it passes through the tube, the refrigerant goes through a desiccant, which removes any residual moisture and filters particles out. 

The refrigerant then exits the tube where it has been cut. The liquid refrigerant falls to the bottom of the accumulator, where it sits until it vaporizes; meanwhile, the refrigerant that is already in a gaseous state passes directly out of the accumulator through an exit tube at the top. This way, only moisture-free, gaseous refrigerant is allowed to make its way out of the accumulator and into the compressor for its next trip through the system. 

How the receiver-drier works

If your vehicle’s AC system has a receiver-drier, it will be found just past the condenser. Like the accumulator, the receiver-drier is a metal canister with two fittings for the refrigerant to be piped in and out. Compared to an accumulator, a receiver-drier is much smaller, having around half the volume.

As the gaseous refrigerant enters the receiver-drier at the top, it passes through a layer of desiccant and filtering material, which removes any residual moisture and particles. The filtered and dried refrigerant, which is already in a gaseous state, rises up through a central pipe and passes through the exit tube at the top.


Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.

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