Accumulator HVAC: Description and Operation

The suction accumulator/drier is mounted on the A/C accumulator bracket and positioned to the left of the radiator. The inlet tube of the suction accumulator/drier is attached to the evaporator to compressor suction line. 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 re-circulate 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.

NOTE: Replacement of the suction accumulator/drier is necessary any time a major component of the refrigerant system is replaced. Failure to replace the suction accumulator/drier could subject the system to excessive moisture accumulation. Major components include:
- 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.

In addition, the suction accumulator/drier should also be replaced if one of the following conditions exist:
- 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.

NOTE: The compressor oil from vehicles equipped with an FS-10 A/C compressor may have a dark color while maintaining a normal oil viscosity. This is normal for this A/C compressor because carbon from the A/C compressor piston rings will discolor the oil.







When replacing the suction accumulator/drier, the procedure given here must be followed to ensure that the total oil charge in the system is correct after the new suction accumulator/drier is installed.
- Drain the oil from the removed suction accumulator/drier into a suitable measuring container. Drill one or two 13 mm (1/2-inch) holes in the bottom of the old suction accumulator/drier to ensure that all the oil has drained out.
- Add the same amount plus 60 ml (2 ounces) of clean new Motorcraft YN-12b refrigerant oil or equivalent meeting Ford specification WSH-M1C231-B to the new suction accumulator/drier.