General Information: Flushing
-- Check the refrigerant quantity in the refrigerant cylinder. There must be at least 7 kg (15.4 lbs) of refrigerant R134a.
If necessary, switch on the heater installed on the refrigerant cylinder for 30 minutes before the first flushing procedure. This increases pressure in the refrigerant cylinder and accelerates charging of the flushing circuit.
-- Drain the A/C Service Station used oil container.
-- Connect the supply hose (high pressure side) of A/C Service Station to the low pressure line leading to the A/C compressor (line with larger diameter) using an adapter. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
-- Connect the return hose (low pressure- or intake side) of the A/C Service Station to the output of refrigerant circuit flushing device.
-- Connect the input on the refrigerant circuit flushing device to the high pressure line leading to the A/C compressor (line with smaller diameter) using an adapter. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
Components are always (with the exception of the electrically-driven A/C compressor) flushed in the opposite direction of refrigerant flow when the A/C system is operating. Refer to FLUSHING CIRCUIT BLOCK DIAGRAMS .
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 operating instructions for the A/C Service Station or refrigerant circuit flushing device.
The filter in the refrigerant circuit flushing device depends on the type and degree of contamination in the flushed refrigerant circuit. It should be replaced after two flushing cycles, at the most. If a heavily contaminated refrigerant circuit is flushed (the refrigerant oil from the refrigerant circuit is black and viscous, or there are many shavings in the refrigerant circuit), the filter should be replaced after flushing the 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 the A/C compressor) is deposited on the viewing glass(es) of the refrigerant circuit flushing device. Clean the viewing glass(es) after flushing and flush the refrigerant circuit once more with one flushing procedure as a check.
Fluid refrigerant cannot be directed with the necessary speed through the expansion valve, restrictor and desiccant bag of certain receiver/dryers. Therefore, these components must be removed and replaced by an adapter. Refer to Heating, Ventilation and Air Conditioning.
Adapters for connecting the A/C Service Station and for bridging certain components of refrigerant circuit. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
-- Switch on the A/C Service Station and flush the refrigerant circuit (duration for one flushing cycle with three flushing procedures is approximately 1 to 1.5 hours for approximately 4 kg (8.8 lbs) of refrigerant R134a).
Flushing the refrigerant circuit is to be performed according to the A/C Service Station operating instructions.
Depending on the A/C Service Station version, the used oil container holds only approximately 125 cm 3 (4.2 oz) of refrigerant oil. In the event a system with a larger refrigerant oil quantity must be flushed, it may be necessary to empty the used oil container after the first flushing procedure of a flushing cycle.
Observe the refrigerant which flows back from the refrigerant circuit. The refrigerant circuit is only clean when the refrigerant flows clear and completely colorless through the viewing glass(es) on the refrigerant circuit flushing device in the A/C service station.
When flushing, the entire amount of refrigerant oil is washed out of the refrigerant circuit (except for minor remains which can be disregarded).
If contamination is especially severe, it may be necessary to perform the flushing cycle twice (two flushing cycles with three flushing operations each). Before the second flushing cycle, the filter on the flushing device must be replaced.