Volkswagen Golf / Golf GTI / Jetta. Manual - part 999

  

 

The A/C compressor extracts the refrigerant gas from the 
evaporator, compresses it and relays it to the condenser.

Note: 

- The A/C compressor contains refrigerant oil, which can be 
mixed with refrigerant R134a under any temperature.  

- The refrigerant for which the A/C compressor is designed 
is listed on the manufacturers plate. A regulator valve 
regulates pressure within the specified range (control 
characteristics) on the low pressure side.  

- In this A/C compressor, the regulator valve is activated 
from outside. 

- Engine should only be started when the refrigerant circuit 
is completely assembled 

 

00-1, Basic rules for working 

on refrigerant circuit

 . 

- The A/C compressor is equipped with a protected oil 
supply, this prevents A/C compressor damage in the event 
that the system is empty. This means that approx.40 to 50 
cm 

3

 of refrigerant oil remains in the A/C compressor. 

A/C compressor without A/C clutch with torsion-
elastic clutch

 

 

A/C compressor is driven directly by the power steering 
vane pump.

 

An overload safeguard is installed on drive shaft of A/C 
compressor which shears off when A/C compressor locks 
up so that power steering vane pump remains functional.

 

The A/C compressor extracts the refrigerant gas from the 
evaporator, compresses it and relays it to the condenser.

Note: 

- The A/C compressor contains refrigerant oil, which can be 
mixed with refrigerant R134a under any temperature.  

- The refrigerant for which the A/C compressor is designed 
is listed on the manufacturers plate. A regulator valve 
regulates pressure within the specified range (control 
characteristics) on the low pressure side.  

- In this A/C compressor, the regulator valve is activated 
from outside. 

- Engine should only be started when the refrigerant circuit 

General information on refrigerant circuit

13/2/2005

  

  

is completely assembled 

 

00-1, Basic rules for working 

on refrigerant circuit

 . 

- The A/C compressor is equipped with a protected oil 
supply, this prevents A/C compressor damage in the event 
that the system is empty. This means that approx.40 to 50 
cm 

3

 of refrigerant oil remains in the A/C compressor. 

Condenser

 

 

The condenser conducts heat from compressed refrigerant 
gas to the ambient air.

 

This condenses the refrigerant gas to liquid.

Evaporator

 

 

The liquid refrigerant evaporates in the evaporator pipe 
coils. The heat required for this is drawn from the air 
flowing on the evaporator ribbing. The air cools off. 
Refrigerant evaporates and is extracted with the absorbed 
heat by the A/C compressor.

 

A defined amount of refrigerant is supplied to the 
evaporator by a restrictor or expansion valve. In systems 
with expansion valve, the flow is regulated so that only 
gaseous refrigerant escapes the evaporator outlet.

General information on refrigerant circuit

13/2/2005

  

  

Reservoir

 

 

The reservoir collects the vaporized and gaseous mixture 
coming from the evaporator to ensure the A/C compressor 
only receives gaseous refrigerant. Gaseous refrigerant is 
formed from the vapor.

 

The refrigerant oil flowing in the circuit is not retained in the 
reservoir as it has an oil drilling.

 

Moisture which has entered the refrigerant circuit during 
repairs will be collected by a filter (desiccant bag) in the 
reservoir.

 

Gaseous refrigerant is extracted with oil by the A/C 
compressor.

Note: 

- Replace the reservoir if refrigerant circuit has been open 
for a long time (beyond the normal repair time) and 
moisture has penetrated inside, or if required due to a 
specific complaint 

 

00-8, Components, replacing

 . 

- Remove sealing plugs - A - and - B - only immediately 
prior to installing. 

- A desiccant bag in an unsealed reservoir is saturated with 
moisture after a short period of time and unusable.  

- When installing, note arrow for direction of flow if 
necessary. 

Restrictor

 

 

The restrictor creates a constriction. This constriction 
reduces the flow and creates high and low pressure sides 
in the refrigerant circuit. Before the restrictor the refrigerant 
which is under a higher pressure is warm. After the 
restrictor the refrigerant which is under a low pressure is 
cold. Before the constriction there is a strainer for 
contaminants and after the constriction there is a strainer, 
to atomize the refrigerant before it reaches the evaporator.

Note: 

- Arrow - A - on restrictor points to evaporator. 

- Replace after each opening of the circuit. 

General information on refrigerant circuit

13/2/2005

  

  

- Note different versions. 

 
 

 Repair Manual, Heating & Air Conditioning, Repair 

Group 87 , 

 Parts Catalog 

Receiver

 

 

The receiver collects the liquid drops and then directs them 
in an uninterrupted stream to the expansion valve. Moisture 
which has entered the refrigerant circuit during repairs will 
be collected by the desiccant bag in the receiver.

Note: 

- Replace the receiver if refrigerant circuit has been open 
for a long time (beyond the normal repair time) and 
moisture has penetrated inside, or if required due to a 
specific complaint 

 

00-8, Components, replacing

 . 

- Only remove sealing plugs shortly before installation. 

- A desiccant bag in an unsealed receiver is saturated with 
moisture after a short period of time and unusable.  

- When installing, note arrow for direction of flow if 
necessary. 

 

The new generation of receivers are installed directly on 
the condenser and possess a dryer cartridge.

Note: 

- Replace the dryer cartridge if refrigerant circuit has been 
open for a long time (beyond the normal repair time) and 
moisture has penetrated inside, or if required due to a 
specific complaint 

 

00-8, Components, replacing

 . 

- Only unpack dryer cartridge immediately prior to 
installation. 

- Dryer cartridge in unsealed packaging is saturated with 
moisture after a short period of time and unusable.  

Expansion valve

 

General information on refrigerant circuit

13/2/2005