Refrigerant Circuit, Cleaning

Components are almost always flushed in the opposite refrigerant flow direction when the A/C system is in operation. (Exception: the electrically-driven A/C compressor). Refer to REFRIGERANT CIRCUIT, CLEANING .

While flushing, contaminants from the refrigerant circuit enter the refrigerant circuit flushing device and the A/C Service Station and are absorbed by the filters and dryers installed there. Depending on the contaminant, these components are to be replaced in shorter intervals according to the Owner's Manual for the A/C Service Station or refrigerant circuit flushing device. Refer to A/C Service Station Owner's Manual.

Depending on the type and degree of contamination in the flushed refrigerant circuit, the filter in the refrigerant circuit flushing device must be changed after five to ten flushing cycles (flushed vehicles) at the latest. If a heavily contaminated refrigerant circuit is flushed (the refrigerant oil from the circuit is black and viscous or there are many shavings in the refrigerant circuit), the filter should be replaced after flushing this refrigerant circuit. With a refrigerant circuit heavily contaminated in this way, it is wise to flush the refrigerant circuit again after changing the filter.

Depending on the type of contamination, dirt (old refrigerant oil and abraded material from A/C compressor) accumulates on the viewing glass of the refrigerant circuit flushing device. If necessary clean the sight glass after flushing and flush the refrigerant circuit with a flushing procedure to check (one cycle is sufficient).

Liquid refrigerant cannot be guided through the expansion valve, restrictor and desiccant bag of certain receiver/dryers at the necessary speed; therefore, these components must be removed and replaced by adapters if necessary. Refer to REFRIGERANT CIRCUIT, CLEANING and Refrigerant Circuit (vehicle-specific service information).

Adapters for connecting the A/C Service Station and for bridging certain refrigerant circuit components. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .

Flushing procedure sequence. Refer to REFRIGERANT CIRCUIT CLEANING PROCESS .

The flushing procedure is to be performed according to the A/C Service Station Owner's Manual. Refer to the A/C Service Station Owner's Manual.

Depending on version of the A/C Service Station, old oil container holds only approximately 125 cm ³ refrigerant oil, in the event a system with a larger quantity of refrigerant oil must be flushed, it may be necessary to drain the old oil container after the first flushing process of one flushing cycle.

Observe the refrigerant which flows back into the A/C Service Station from the refrigerant circuit, only when the refrigerant streams clear and completely colorless through the sight glass of refrigerant circuit flushing device in the A/C Service Station is the refrigerant circuit cleaned.

All the refrigerant oil is washed out of the refrigerant circuit during flushing (except for a very small amount in the evaporator, however this can be disregarded).

If heavily contaminated, it may be necessary to perform the flushing procedure twice (two flushing cycles with four flushing operations each).

There is a specific prescribed amount of refrigerant oil in the replacement A/C compressor. On vehicles with two evaporators, it may be necessary to add an additional certain amount of refrigerant oil into the circuit. Refer to APPROVED REFRIGERANT OILS AND REFRIGERANT OIL CAPACITIES (vehicle-specific service information).

If the A/C compressor is not replaced, replace the refrigerant oil quantity in the A/C compressor according to the specified capacity (pour out or flush the refrigerant oil and add the specified amount into the A/C compressor or refrigerant circuit). Refer to COMPONENTS, REPLACING and APPROVED REFRIGERANT OILS AND REFRIGERANT OIL CAPACITIES (vehicle-specific service information).