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