RECEIVER-DRYER – WHAT IS IT & WHAT GOES WRONG?

 Situated between the expansion valve and the condenser, the receiver-dryer can either be welded to the condenser, or unscrewed and removed separately. Not only does it filter out any solid contaminations in the compressor oil but also, considering that the lubricant is hygroscopic, it captures the moisture and prevents it from circulating. Whenever the air-conditioning circuit is unpressurised, it risks being exposed to exterior air, causing the dryer to become saturated rapidly with atmospheric moisture. As such, you should factor-in its replacement cost when you’re getting quotes to repair a leaky system.

DIY receiver-dryer replacement on a discharged system is feasible. You should find sealing plugs on the replacement parts, which must be removed as late as possible into the repair, ie. just before fitting. Have the system evacuated, pressure-checked and re-gassed as soon as possible afterwards. Many air-conditioning specialists recommend renewing the receiver-dryer regardless of its condition every 2-3 years. Interestingly, this tends not to be mentioned in manufacturer service intervals, possibly for cost and accessibility reasons.

On some cars, you may find that an accumulator replaces the receiver-dryer. Instead of being fitted on the high-pressure side of the system, it mounts to the gaseous side between the evaporator outlet and the compressor, suction port. Not only does it fulfil the receiver-dryer’s moisture and filtration tasks but it also protects the compressor by preventing non-compressible liquid refrigerant from entering it. Accumulators tend to be fitted to cars that use orifice tubes instead of expansion valves.