Accumulator HVAC: Description and Operation

NOTE: Replacement of the suction accumulator/drier is necessary any time a major component of the refrigerant system is replaced. Major components include the following:

- A/C condenser core
- A/C compressor
- A/C evaporator core
- a refrigerant hose/line

An A/C evaporator core orifice or O-ring seal is not considered a major component but the A/C evaporator core orifice should be replaced whenever the A/C compressor is replaced for lack of performance.

The suction accumulator/drier is mounted on the A/C accumulator bracket and positioned to the right of the radiator. The inlet tube of the suction accumulator/drier is attached to the A/C evaporator core. The outlet tube attaches to the A/C manifold and tube.

After entering the inlet of the suction accumulator/drier, heavier oil-laden refrigerant contacts an internally mounted dome (which serves as an umbrella) and drips down onto the bottom of the canister.
- A small diameter oil bleed hole in the bottom of the vapor return tube allows the accumulated heavier liquid refrigerant and oil mixture to re-enter the compressor suction line at a controlled rate.
- As this heavier mixture passes through the small diameter liquid bleed hole, it has a second chance to vaporize and recirculate through the A/C compressor without causing compressor damage due to slugging.
- A fine-mesh screened filter fits tightly around the bottom of the vapor return tube to filter out refrigerant system contaminant particles.
- A desiccant bag is mounted inside the canister to absorb any moisture which may be in the refrigerant system.
- A fitting located on the top of the suction accumulator/drier is used to mount the A/C cycling switch. A long-travel, Schrader-type valve stem core is installed in the fitting opening to prevent refrigerant loss when the A/C cycling switch is removed.

When it is necessary to measure the quantity of refrigerant oil in the suction accumulator/drier, drill two 13 mm (1/2 inch) holes in the body of the suction accumulator/drier and drain oil through the holes.

In addition to the preceding condition, the suction accumulator/drier should also be replaced if one of the following conditions exists:
- The suction accumulator/drier is perforated.
- The refrigerant system has been opened to the atmosphere for a period of time longer than required to make a minor repair.
- There is evidence of moisture in the system such as internal corrosion of metal refrigerant lines, or the refrigerant oil is thick and dark.