Service Connection Differences, Depending On Refrigerant (R134A Or R1234YF)

Only use valves and connections that are resistant to the respective refrigerant (R134a and/or R1234yf) and the corresponding refrigerant oil. Refer to the Parts information.

The service connections on the refrigerant circuits are designed so that only the service couplings provided for the intended refrigerant (R134a or R1234yf) can be connected.

These illustrations show service connections that have a Schrader valve (needle valve or push pin) installed in them. Depending on the vehicle version, the refrigerant, etc., service connections with a primary sealing valve (ball valve) may also be installed (other technology).

Allocation in the vehicle and on the refrigerant circuit. Refer to COMPONENT LOCATION OVERVIEW - COMPONENTS OUTSIDE OF PASSENGER COMPARTMENT  and SYSTEM OVERVIEW - REFRIGERANT CIRCUIT .

Different connections (outer diameter) for high pressure and low pressure side.

Before removing the valves or valve inserts, discharge the refrigerant circuit. .

Valve, removing and installing at service connection on low and high pressure side. Refer to VALVE, REMOVING AND INSTALLING AT SERVICE CONNECTION ON LOW AND HIGH PRESSURE SIDE .

Always install the closure caps with a seal.

Depending on the manufacturer, there are different versions of the service connections -C and F- for refrigerant R134a and refrigerant R1234yf with different closure caps -A and D- and valves -B and E-. Pay attention to the correct allocation. Refer to the Parts information.

The closure caps -A and D- for the service connections on the R134a refrigerant circuit are currently black. The closure caps for the service connections on the R1234yf refrigerant circuit are currently gray. The type of refrigerant (such as "R1234yf") may also be imprinted on the closure caps.

After connecting, carefully install the service coupling hand wheel just far enough into the quick-release coupling adapter until the valve -B and E- is securely opened in the service connection (pay attention to the pressure gauge, do not put too much pressure on the valve -B and E-).

The service connections -C and F- on an R134a and R134yf refrigerant circuit are designed so that only certain service couplings can be connected for each of the refrigerants (different dimensions. Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF) ).

For example, the service connections -C and F- are soldered into a refrigerant line and therefore cannot be replaced separately.

To remove and install the valves -B and E- (when the refrigerant circuit is discharged), use, for example, an adapter from the :T10364  . Refer to VALVE, REMOVING AND INSTALLING AT SERVICE CONNECTION ON LOW AND HIGH PRESSURE SIDE

Due to the low tightening specification, only tighten the valves -B and E- carefully. Refer to VALVE, REMOVING AND INSTALLING AT SERVICE CONNECTION ON LOW AND HIGH PRESSURE SIDE

There are different versions of these valves, therefore the tightening specifications are different. For a valve insert -C- with a VG5 thread (5.2 x 0.7 mm, tire valve), the tightening specification is 0.4 Nm. +- 0.1 Nm, on a valve insert with a M6 x 0.75 mm thread, the tightening specification is 0, 9 Nm +- 0.1 Nm and on a valve insert with a M8 x 1.0 mm thread, the tightening specification is 2.0 Nm +- 0.2 Nm.

There are different versions of these valve caps -A and D-, which means there are different tightening specifications. A valve cap with an M8 x 1mm or M10 x 1mm thread has a tightening specification of 0.4 Nm +- 0.1 Nm.