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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017
CAUTION
Risk of freezing injury caused by escaping pressurised refrig‐
erant.
There is a risk of injury to the skin and parts of the body due to
freezing.
– Wear protective gloves.
– Wear protective goggles.
– If, when loosening the handwheel of the service coupling,
refrigerant escapes from the refrigerant line for longer than
1 second, screw in the handwheel and renew the defective
valve.
– Extract refrigerant and open the refrigerant circuit immedi‐
ately afterwards.
– If more than 10 minutes have passed since the refrigerant
was extracted, repeat the extraction process before opening
the refrigerant circuit. Pressure could build up in the refrig‐
erant circuit from continued evaporation.
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Different versions of service couplings
♦ On one version of service coupling, the space between the
valve in the service connection of the refrigerant circuit and the
valve in the service coupling is vented externally when the
handwheel is unscrewed. On these service couplings, the
valve in the service connection of the vehicle is closed first,
followed by the valve in the service coupling for the charge
hose of air conditioner service station when the handwheel of
the service coupling is unscrewed. As it is unscrewed further,
the pressure still present between the two valves is released
3
via an additional valve (approx. 2 cm of refrigerant). Should
one of these two valves (the valve in the service connection of
the vehicle or the valve in the service coupling for the charge
hose) not close properly, the whole refrigerant could escape
out of the refrigerant circuit of the vehicle or the charge hose.
♦ On another version of service coupling, the space between the
valve in the service connection of the refrigerant circuit and the
valve in the service coupling is not vented externally when the
handwheel is unscrewed. This version features a valve that is
open when the service coupling is connected, which facilitates
pressure compensation between the space to the valve in the
service connection of the refrigerant circuit and the charge
hose connected to the service coupling. On this version, no
refrigerant escapes when the handwheel of the service cou‐
pling is unscrewed, which is why the refrigerant has to be
extracted from the charge hoses into the air conditioner serv‐
ice station here before the service couplings are disconnected.
If a large amount of refrigerant is recovered here, for example,
after a pressure test or after charging the refrigerant circuit
(more than approx. 50 g), this is an indication that a valve in
one of the service connections of the refrigerant circuit could
be leaking and refrigerant is escaping from the refrigerant cir‐
cuit of the vehicle (extract refrigerant and renew the defective
valve)
Before extracting the refrigerant from the charge hoses into the
air conditioner service station , unscrew the handwheels of both
service couplings as far as they will go.
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Rep. gr.87 - Air conditioning system
GETth
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