Opel Frontera UBS. Manual - part 903

1B – 6 AIR CONDITIONING

DUAL PRESSURE SWITCH

The dual pressure switch is installed on the upper
part of the receiver/drier, to detect excessively high
pressure (high pressure switch) and prevent
compressor seizure due to the refrigerant leaking
(low pressure switch), switching the compressor
“ON” or “OFF” as required.
The pressure switch connector is waterproof type.

•

Low-pressure control

kpa (kg·cm

/ PSI)

Compressor

ON: 205.9 ± 30 (2.1 ± 0.3 / 30 ± 4)

(Except 6VD1 / 6VE1, LHD model)
186 ± 30 (1.9 ± 0.3 / 27 ± 4)
(only for 6VD1 / 6VE1, LHD model)

OFF: 176 ± 20 (1.8 ± 0.2 / 26 ± 3)

•

High-pressure control
Compressor

ON: 2354 ± 196 (24.0 ± 2.0 / 341 ± 28)
OFF: 2942 ± 196 (30.0 ± 2.0 / 427 ± 28)

TRIPLE PRESSURE SWITCH

Triple pressure switch is installed atop the receiver/
drier. This switch is constructed with a unitized type
of two switches. One of them is a low and high
pressure switch (Dual pressure switch) to switch
“ON” or “OFF” the magnetic clutch as a result of
irregularly high-pressure or low-pressure of the
refrigerant. The other one is a medium pressure
switch (Cycling switch) to switch “ON” or “OFF”
the condenser fan sensing the condenser high side
pressure.

•

Low-pressure control

kpa (kg·cm

/PSI)

Compressor

ON: 186 ± 30 (1.9 ± 0.3 / 27 ± 4)
OFF: 176 ± 20 (1.8 ± 0.2 / 26 ± 3)

•

Medium-pressure control
Condenser fan

ON: 1471 ± 98 (15.0 ± 1.0 / 213 ± 14)
OFF: 1079 ± 98 (11.0 ± 1.0 / 156 ± 14)

•

High-pressure control
Compressor

ON: 2354 ± 196 (24.0 ± 2.0 / 341 ± 28)
OFF: 2942 ± 196 (30.0 ± 2.0 / 427 ± 28)

EXPANSION VALVE

This expansion valve (1) is internal pressure type
and it is installed at the evaporator intake port.
The expansion valve converts the high pressure
liquid refrigerant sent from the receiver/drier to a
low pressure liquid refrigerant by forcing it through
a tiny port before sending it to the evaporator (2).
This type of expansion valve consists of a
temperature sensor, diaphragm, ball valve, ball
seat, spring adjustment screw, etc.
The temperature sensor contacts the evaporator
outlet pipe, and converts changes in temperature to
pressure. It then transmits these to the top chamber
of the diaphragm.
The refrigerant pressure is transmitted to the
diaphragms bottom chamber through the external
equalizing pressure tube.
The ball valve is connected to the diaphragm. The
opening angle of the expansion valve is determined
by the force acting on the diaphragm and the spring
pressure.
The expansion valve regulates the flow rate of the
refrigerant. Accordingly, when a malfunction occurs
to this expansion valve, both discharge and suction
pressures get low, resulting in insufficient cooling
capacity of the evaporator.

Pressure switch

Receiver/Drier

Triple pressure switch

Condenser fan

Condenser

875RY00003

874RY00003

AIR CONDITIONING 1B – 7

EVAPORATOR

The evaporator cools and dehumidifies the air
before the air enters the vehicle. High-pressure
liquid refrigerant flows through the expansion valve
(1) into the low-pressure area of the evaporator (2).
The heat in the air passing through the evaporator
core is lost to the cooler surface of the core, thereby
cooling the air.
As heat is lost between the air and the evaporator
core surface, moisture in the vehicle condenses on
the outside surface of the evaporator core and is
drained off as water.
When the evaporator malfunctions, the trouble will
show up as inadequate supply of cool air. The
cause is typically a partially plugged core due to
dirt, or a malfunctioning blower motor.
The evaporator core with a laminate louver fin is a
single-sided tank type where only one tank is
provided under the core.

ELECTRONIC THERMOSTAT

The thermostat consists of the thermosensor (1)
and thermostat unit (4) which functions electrically
to reduce the noises being generated while the
system is in operation.
The electronic thermosensor (1) is mounted at the
evaporator core (2) outlet and senses the
temperature of the cool air from the evaporator (3).
Temperature signals are input to the thermostat
unit. This information is compared by the thermo
unit and the results in output to operate the A/C
Thermostat relay and turn the magnetic clutch
“ON” or “OFF” to prevent evaporator freeze-up.
A characteristic of the sensor is that the resistance
decreases as the temperature increases and the
resistance increases as the temperature decreases.

REFRIGERANT LINE

Restrictions in the refrigerant line will be indicated by:
1. Suction line; A restricted suction line will cause

low suction pressure at the compressor, low
discharge pressure and little or not cooling.

2. Discharge line; A restriction in the discharge line

generally will cause the discharge line to leak.

3. Liquid line; A liquid line restriction will be

evidenced by low discharge and suction
pressure and insufficient cooling.

Refrigerant flexible hoses that have a low
permeability to refrigerant and moisture are used.
These low permeability hoses have a special nylon
layer on the inside.

SERVICE CHARGE VALVES

The charging hoses have a quick-joint type fitting,
to reduce refrigerant loss during removal and
installation.

Reinforcement layer(Polyester)

Resin layer(Nylon)

Internal rubber layer

External rubber layer

874RY00003

874RX022

1B – 8 AIR CONDITIONING

AIR CONDITIONING PARTS

Legend

(1)

Liquid Line (High-Pressure Pipe)

(2)

Pressure Switch

(3)

Receiver Drier

(4)

Discharge Line (High-Pressure Hose)

(5)

Suction Line (Low-Pressure Hose)

(6)

Compressor

(7)

Condenser Assembly

(8)

Serpentine Belt

(9)

Compressor Bracket

(10)

Drain Hose

(11)

Evaporator Assembly

(12)

O-ring

6VD1/6VE1 (RHD)

852RY00006

AIR CONDITIONING 1B – 9

852RY00008

This illustration is based on RHD

A/C switch

Drain hose

Suction line (Low-pressure hose)

Discharge line (High-pressure hose)

Compressor bracket

Pressure
switch

Receiver/drier

Compressor

Relay

Condenser assembly

Drive belt

O-ring

Suction line
(Low-pressure pipe)

Evaporator assembly

Liquid line(High-pressure pipe)

Liquid line
(High-pressure pipe)

4JG2 (R/LHD)

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