What is a receiver drier, how does it work and why should you change it?
The receiver drier also referred to as a filter-drier or receiver-dehydrator, is a filtering unit located on the high-pressure side of an A/C loop, normally between the condenser and expansion valve. Recognisable as a sealed metal can with an inlet and outlet, the receiver drier plays an important role in safeguarding compressor longevity and optimising system operation.
There are three main functions of a receiver drier:
1. Refrigerant and lubricant storage – Similar to an accumulator, the receiver drier serves as a temporary holding container when refrigerant and oil are not required for system operation, for example during periods of low cooling demand.
2. Protection of the A/C system again moisture damage – Unwarranted moisture can lead to internal corrosion, as well as potentially compromising the performance of a compressor’s lubricating oil. The receiver drier contains desiccant, a substance with absorbent properties which is intended to deal with any water entering the A/C system, hence the “drier” name.
3. Filtration unit – Designed within most receiver driers is a filter which serves to trap debris circulating an A/C system and prevent metal chips and particles from clogging a condenser/evaporator or seizing a compressor.
The need to regularly replace your receiver drier is not a myth!
We strongly recommend that you install a new receiver drier whenever you replace a compressor or open a system for service; many compressor warranties also stipulate this as a requirement.
Bear in mind that the unit is constantly under strain - filter layers suffer wear, whilst desiccant can only absorb a finite amount of moisture and is severely challenged not only by system openings for services/leaks but also by pollution due to incorrect or excessive use of additives or lubricants.
Poor performance, abnormal system pressures, circuit clogs and worse are all likely outcomes if your receiver drier is worn out or spoiled so don’t run the risk!