Vehicle Air Conditioning Compressors

We supply or supply and fit a wide range of vehicle air conditioning compressors to fit Car Van Motorhome Truck Bus Agricultural Tractor Combine Construction Plant Bulldozer Loading Shovel Excavator Forestry Plant

Mobile Air Conditioning and Autoelectrical Service covering Shrewsbury, Oswestry, Whitchurch, Telford, Shropshire and Welshpool Mid Wales areas.

Telephone mobile 07703 558610 www.autoelectrics.net

Air Conditioning Compressor - Function

The air conditioning compressor pumps refrigerant gas to increase pressure and cause flow of refrigerant around the vehicle air conditioning / refrigeration circuit. Refrigerant changes state from gas to liquid and vice versa depending on pressure and temperature enthalpy.

AC Compressor - Operation

Low pressure, low temperature refrigerant gas is drawn in to the compressor through the compressor suction port.
Compression of refrigerant gas raises both pressure and temperature.
High pressure refrigerant gas exits from the compressor discharge outlet port causing refrigerant flow around the air conditioning system.
The compressor can only compress gas. If slugs of liquid enters the compressor component damage will result.

Aircon Compressor - Failure

Apart from general wear and tear, vehicle air conditioning compressors can deteriorate due to lack of lubrication and moisture damage causing rust which may lead to mechanical damage and possible seizure.
Filter drier dessicant packs deteriorate over time and may break up causing debris to pass around the air conditioning system. Blockage at thermal expansion valve and internal compressor components may result. Diagnosis using pressure guages may indicate excessive high pressure reading. Compressor operating at too high pressure may lead to subsequent component damage.
Compressor clutch failure results in loss of compressor drive and excess noise.
Incorrect lubricants may also cause premature failure.

Electromagnetic Clutch driven Compressor

An electrical control circuit monitors temperature demand and refrigerant pressures.
The compressor clutch pulley is belt driven.
Providing correct conditions exist as the engine rotates, the control circuit causes the compressor relay to switch power and activate the electromagnetic clutch solenoid.
Compressor clutch engagement causes rotation of the air conditioner compressor pump to create pressure and encourage flow of refrigerant around the air conditioning circuit.

Electronically Controlled Clutchless Compressor

Certain vehicle refrigeration and air conditioning systems feature an electronically controlled compressor.
Compressor variants include:

Variable rotational speed

Variable displacement

Refrigerant metering control

allowing increased efficiency by reduced power consumption to save fuel and energy.

Compressor Power Source

Commercial vehicle refrigeration systems may be powered by a diesel engine or electric motor and inverter.
Most vehicle air conditioning compressors are engine pulley driven via an auxilliary drive belt, some systems eg truck cab fridges and roof mount air conditioning units may use hermetically sealed electric compressors.

Vehicle Climate Control Systems - Computerised Electronic Diagnostics

Vehicle climate control systems are complex and may feature

an electronic control unit

input sensors

detecting engine speed, compressor speed, refrigerant temperature and pressure, vent and ambient air temperature

output actuators

controlling electromagnetic valves, air flap blend doors, recirculation, and stepper motors.
When an air conditioner or refrigeration system fault is detected this may cause the electronic climate control unit to log error fault codes and controller system lock out preventing air conditioning compressor operation.

Supply of vehicle air conditioning compressors

Compressors supplied for Vans * Trucks * Minibuses * Coaches * Ambulance * Construction equipment * Quarry plant * Agricultural machinery * Marine * Motorhome

Air Conditioning Compressors supplied replacing :
CARGO
DENSO
HELLA
SANDEN ; SD5H14
SD7H15
SD7H15HD
TECUMSEH
York

Compressor Oils

Air conditioning and refrigeration compressors have moving parts which require specialised lubrication.
Certain vehicle air conditioning systems may require special compressor lubrication oils injected in to the refrigerant circuit during service.
Vehicle refrigerant leaks may cause loss of this compressor lubrication oil and eventually result in compressor damage and seizure.

There is a variety of oil specifications for various types of vehicle air conditioning compressors and operating parameters.

Synthetic Refrigeration Oils

PAG (Polyalkylene Glycol) Oils

PAO (Polyalphaolefin) Oils

POE (Polyolester) Oils

Mineral Refrigeration Oils

Aircon Compressor Lubrication

Lack of Refrigerant oil in system causing insufficient lubrication resulting in compressor damage or seizure.
Incorrect Refrigerant Oil :
POE oil and PAG oil do not mix well

Possible Causes of Air Conditioning Compressor Failures

Moisture and the Air conditioning Compressor

Moisture and liquid can damage AC compressors because moisture within the refrigerant circuit can mix with oil to form acids which corrode the air conditioner system components.

Dirt ingress into refrigeration circuit causing component wear

The receiver dryer acts as a filter to remove some moisture from the refrigerant circuit.

Liquid slugging of the compressor

Liquid refrigerant entering the compressor may cause damage.

Contamination

Ice, dirt or debris entering the refrigerant circuit may cause damage to the compressor

Refrigerant circuit blockage

Refrigeration system flow restrictions can cause the compressor to run hotter than normal.
Possible causes:

Receiver Dryer Filter dessicant pack disintegrated causing blockage of system

Thermal Expansion valve stuck or blocked

Rubber hose deteriorated or collapsed internally causing blockage

Vehicle Air Conditioning Compressor Refrigerant Leaks

Air conditioning or refrigeration systems should not leak refrigerant.
However, due to automotive system design using compressors with open shaft seals, minor leakage can occur over periods of time.
If the vehicle air conditioning has not been used regularly the compressor shaft seal may lack lubrication then start to leak.
A pressure switch or sensor is often fitted in the refrigerant circuit to prevent compressor operation should system pressure drop or increase beyond preset parameters.
Vehicle manufacturers suggest periodic air conditioning system inspection and refrigerant regas.
Other potential leakage points are compressor casing porosity , pipework o-rings and gaskets.
Leak detection methods may include Nitrogen pressure test, electronic leak detection, UV dye leak locator.

Vehicle Air Conditioning Compressor Replacement

Refrigerant Recovery

Prior to replacement of the vehicle air conditioning compressor, all refrigerant must be safely recovered.

Refrigerant recovery by F-Gas certified personnel is a legal obligation for air conditioning systems containing R134a (and most other refrigerants) prior to removing an air conditioning compressor or refrigeration gas circuit component.
System flushing to remove contaminants is recommended before fitting replacement compressors.

OFN Pressure test

A Nitrogen pressure test should be carried out to check for leaks after fitting new components before refrigerant is added.

Vacuum

Following system evacuation, a vacuum hold test is also advised prior to regas.

Regas Refrigerant Recharge

Air conditioning system recharge with specified refrigerant can be carried out using service ports.
There is a variety of service ports fitted to vehicle refrigeration and air conditioning systems which differ often dependant on the refrigerant type being used.
for example
Low side R134a quickfit coupler and High side R134a quickfit coupler have different dimensions compared to
Low side 1234YF coupler, High side 1234yf coupler,
1/4 SAE threaded and Rotalock fittings.

Refrigeration System Operational Checks

High and Low side refrigerant circuit system operating pressures should be checked after regassing to verify correct operation.

Final leak checks of the refrigerant circuit should be completed to ensure FGAS regulation compliance.

Replacement Air Conditioning Compressors

Compressors or parts available for
BEHR , BOSCH , CALSONIC, CHRYSLER, DENSO, FORD, GM, HITACHI, KIKI, MAGNETTI MARELLI, MATSUSHITA, MITSUBISHI, PANASONIC, SANDEN SD6V08, SD6V12 , SD7B10, SD7H15 , SD7V16, SD508,SD709, SELTEC, SEIKO SEIKI, TECUMSEH, YORK, ER210L, ER210R, ZEXEL,

Oem Manufacturers names or part numbers used for reference purposes only.

Vehicle Air Conditioning Mobile Service Areas:

Service engineer callout covers Shropshire & Mid Wales areas (*subject to availability):
Shrewsbury - Atcham - Alberbury - Bayston Hill - Dorrington - Church Stretton Craven Arms - Hadnall - High Ercall - Shawbury - Market Drayton - Pontesbury - Minsterley - Rowton - Halfway House - Much Wenlock - Ludlow - Oswestry - Wem - Whitchurh - Ellesmere - Telford - Shifnal - Cosford - Albrighton -Newport -
Mid Wales : Welshpool - Middletown - Trewern - Guilsfield - Ardleen - Berriew - Llanymynech - Llanfair - Poolquay - Churchstoke - Pentre - Melverley - Abermule - NewtownWem