A/C Accumulator
A canister in A/C systems using an orifice tube, located on the low-pressure side, that filters refrigerant and prevents liquid from entering the compressor.
An A/C accumulator is a metal canister used in air conditioning systems that utilize an orifice tube for refrigerant metering. Unlike a receiver-drier, which is located on the high-pressure side, the accumulator is located on the low-pressure side of the system, connected between the evaporator outlet and the compressor inlet.
The accumulator's main job is to prevent liquid refrigerant from entering the A/C compressor. Compressors are designed to compress gas; liquid refrigerant cannot be compressed, and if it enters the compressor (a condition known as slugging), it will destroy the internal valves and pistons. The accumulator acts as a holding tank, allowing liquid refrigerant to evaporate into a gas before being drawn into the compressor. Like the receiver-drier, it also contains a desiccant to absorb moisture and a filter to trap debris.
If the accumulator fails or the desiccant bag inside ruptures, moisture and debris will circulate through the system, leading to acid formation, compressor failure, and clogged lines. Symptoms of a saturated accumulator include poor cooling, A/C clutch cycling issues, and system leaks.
Replacing the accumulator is a mandatory step whenever the A/C system is opened for servicing, as exposing the internal desiccant to atmospheric air quickly saturates it with moisture, rendering it useless.