A/C Accumulator Function
Accumulators are used on fixed orifice tube systems to collect excess liquid that may leave the evaporator’s outlet tube. Compressors are incapable of compressing liquid. To prevent this, the accumulator is designed to allow only a regulated amount of oil and liquid refrigerant to enter the compressor for lubrication and cooling.
The accumulator is created with an outlet tube that incorporates a unique u-shaped tube with an oil bleed hole located at its base. As the excess liquid and oil enter the tank from the inlet tube, they drop to the bottom of the canister. Vapor flows through a desiccant before travelling to the outlet tube. As the vapor passes through the outlet tube, it draws a regulated amount of liquid refrigerant and oil through the bleed hole and onto the compressor with it.
An accumulator is used with fixed orifice tube systems and a receiver drier is used with the TXV or thermostatic expansion valve type system. They both contain a desiccant bag. The desiccant absorbs and stores any moisture that would contaminate the refrigerant. This moisture alters the chemical structure of the 134a and may freeze, corrode, or damage vital system components. When it’s saturated with moisture, the entire accumulator must be replaced.