General Installation Sequence

WARNING: This page is about a different variant/trim than selected.

NOTE: Excessively high pressure in refrigerant circuit

Risk of damage to air-conditioning compressor
→ Do not allow low-pressure gauge to go above 3 bar.

Information

On air-conditioning service equipment with a transparent oil separator, read off and take note of the oil level before removing refrigerant.
Do not carry out this step on empty air-conditioning systems (pressure gauge approx. 0 bar) because if you do, air will get into the refrigerant bottle.
If the vehicle is cold, it may be necessary to repeat the suction procedure until all refrigerant has been removed from the air-conditioning system. This step is carried out automatically with some units.

Information

There must be a minimum amount of refrigerant in the air-conditioning servicing equipment for flushing (at least 4 kg R1234yf and at least 8 kg R134a). The minimum quantity specifications for flushing the refrigerant circuit take precedence in the relevant operating instructions.

Information

Instructions in the operating instructions for the air-conditioning servicing equipment take precedence. The procedure described here may differ from the description provided by the respective air-conditioning servicing equipment manufacturer.

Information

If air-conditioning servicing equipment without programming is used for flushing, the procedure must be performed manually (evacuate, flush 4 times using at least 2 kg of refrigerant each time and extract the refrigerant again, evacuate).

Basic circuit diagrams (flushing circuits) for cleaning with refrigerant R1234yf and R134a

With 1 or 2 evaporators

With and without high-voltage system

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Basic circuit diagram for cleaning refrigerant circuit

1	Air-conditioning servicing equipment (with flushing device)
2	High-pressure hose from air-conditioning servicing equipment
3	Adapter for connection for the low-pressure side on the refrigerant circuit
4	Connection for low-pressure line to air-conditioning compressor
5	Adapter for the removed expansion valve
6	Evaporator
7	Connection for high-pressure line to desiccator
8	Adapter for bridging the removed desiccator
9	Hose for bridging components
10	Condenser
11	Connection for high-pressure line to air-conditioning compressor
12	Adapter for connection for the high-pressure side on the refrigerant circuit
13	Hose on flushing device
14	Flushing device for refrigerant circuits
15	Low-pressure hose on air-conditioning servicing equipment
16	Adapter for closing off the outlet to the second evaporator
17	Adapter for closing off the outlet to the second evaporator
18	Connection from low-pressure side on refrigerant circuit to the second evaporator
19	Connection from high-pressure side on refrigerant circuit to the second evaporator
20	Adapter for the removed expansion valve on the second evaporator
21	Second evaporator

Install the relevant adapter instead of the expansion valve and tighten it to the same tightening torque as for the expansion valve.
> 8X00IN OVERVIEW OF ADAPTERS FOR CLEANING THE REFRIGERANT CIRCUIT

> 877019 REMOVING AND INSTALLING EXPANSION VALVE
1. 2.1 If you do not have an adapter for the expansion valve: Drill out expansion valve (see "Converting expansion valve for the adapter").
2. 2.2 Clean the drilled out expansion valve to remove any bits left after machining (chips) and install it.
  > 877019 REMOVING AND INSTALLING EXPANSION VALVE
Connect high-pressure hose of the air-conditioning servicing equipment (generally red) to the low-pressure line (line with a larger diameter) for the air-conditioning compressor using the adapter (see overview of adapters
> 8X00IN OVERVIEW OF ADAPTERS FOR CLEANING THE REFRIGERANT CIRCUIT

).
1. 3.1 To do this, the quick connector on the high-pressure line of the air-conditioning servicing equipment must be removed.
Connect low-pressure hose of the air-conditioning servicing equipment (generally blue) to the outlet of the flushing device (chip filter) -14- for refrigerant circuits using the quick connector.
Connect hose on flushing device -13- of the air-conditioning servicing equipment to the high-pressure line (line with the smaller diameter) for the air-conditioning compressor using the adapter (see overview of adapters
> 8X00IN OVERVIEW OF ADAPTERS FOR CLEANING THE REFRIGERANT CIRCUIT

).
Hybrid only: Close shut-off valve for the high-voltage battery refrigerant circuit.
1. 6.1 > 9900 - PIWIS Tester 3 must be connected and ignition switched on.
2. 6.2 Select the required vehicle type.
3. 6.3 Select the Thermal management control unit in the overview.
4. 6.4 Drive links/checks must now be selected.
5. 6.5 Select the drive link Refrigerant shut-off valve (AVK8) and press F12
6. 6.6 Select the activation value Off and press F8 to start.
Information
- Only when clear, totally colourless refrigerant flows through the inspection glass of the flushing device for refrigerant circuits into the air-conditioning servicing equipment is the refrigerant circuit cleaned.
- Flushing washes all refrigerant oil out of the refrigerant circuit (except for minute traces - but these can be ignored).
- If the refrigerant circuit is extremely dirty, it may be necessary to perform the flushing cycle twice (two flushing cycles with three flushing procedures each). Before starting the second flushing cycle, the filter on the flushing device must be replaced by a new filter (see Workshop Equipment and Special Tools Information).
Flush the refrigerant circuit as described in the operating instructions for the air-conditioning servicing equipment.
Information
- If a flushed refrigerant circuit will not be assembled again immediately after flushing, leave the adapters on the connections and close off the connections on the adapters using > VAS 6338/30A - sealing caps .
After flushing, check the pressure in the refrigerant circuit. There must be no overpressure in the refrigerant circuit (evacuate the refrigerant circuit again briefly if necessary).
Close off connections to the air-conditioning servicing equipment from the refrigerant circuit in the vehicle. There must be no overpressure in the refrigerant circuit.
The following components must be replaced if the air-conditioning compressor is seized up: Air-conditioning compressor, expansion valve, desiccator or condenser with desiccator.
If the refrigerant circuit is cleaned without causing damage, only the desiccator or the condenser with desiccator must be replaced.
Determine refrigerant oil quantity for the refrigerant circuit.
1. 11.1 A new air-conditioning compressor is pre-filled with a certain amount of refrigerant oil and this must be taken into account when determining the total amount of refrigerant oil.
2. 11.2 If the same air-conditioning compressor is installed again, the amount of refrigerant oil in the air-conditioning compressor must be measured in order to determine the total amount of refrigerant oil.