Essentially the job of the accumulator is very similar to that of the receiver drier. It collects water, dust, dirt and debris from the system and stores them in desiccant. It is also a serviceable item – just like the receiver drier.

The difference is that the accumulator is fitted after the evaporator. This means it filters a gas, not a liquid refrigerant, and it is on the low pressure side of the system, not the high.

The accumulator therefore is very important. It is the last component before the compressor. Accumulators are noticeably larger than receiver driers. This is because they have a large volume to reduce the pressure of the gas even further – ensuring that there will be no liquid entering the compressor. As mentioned before, low pressure means low temperature. It is often therefore referred to as a reservoir.

Accumulator Dehydrator (A/D)

• Separates liquid and vapor refrigerant.
• It stores liquid refrigerant and lubricant.
• Contains drying agent (desiccant).
• Removes moisture from refrigerant as it passes over the drying agent.
• Has lubricant bleed hole to provide a lubricant return path to compressor.

Replace the accumulator dehydrator (A/D) or receiver drier (R/D) when replacing the compressor, when the system has been open for an extended period of time or when sealant or other system debris is present. On condensers with an integral R/D where the desiccant is removable, replace the desiccant only, not the condenser. If the desiccant cannot be replaced, condenser replacement is required.