Mobile service and repair of lorry cab air conditioning systems for the Road Haulage industry
Truck Air Conditioning Mobile Service covers Shrewsbury, Oswestry, Whitchurch, Telford, Shropshire and Welshpool Mid Wales areas.
Telephone 01743 884888 or mobile 07703 558610 www.autoelectrics.net
Lorry cab air conditioning reduces in cab temperature to provide a comfortable working environment.
Sunlight radiation on cab glass combined with heat from the truck engine can cause in cab temperatures to soar during summer months.
The clean filtered air provided by the truck air conditioning system improves the driver's working environment allowing cab windows to remain closed so reducing noise.
Many truck cab air conditioning systems use R134a refrigerant.
R134a is a HFC refrigerant requiring recovery by an Fgas certified engineer before any attempt to dismantle the air conditioning system is undertaken.
We have facilities to recover R134a from lorry air conditioning systems.
It is illegal for truck fitters to just undo pipes and let refrigerant go.
The hgv truck aircon compressor is usually belt driven via auxilliary drive belt from the crankshaft pulley.
Aircon compressor drive is engaged and disengaged by applying electrical power to the compressor clutch.
During the air conditioning operation the ac compressor intakes refrigerant gas at low pressure and discharges gas at high pressure.
Increase of gas pressure also increases temperature.
The aircon compressor may not operate if the refrigerant pressure is too low.
Electrical faults may prevent compressor clutch engagement.
Changing the truck air conditioning compressor will first require safe recovery of air conditioning refrigerant
Refrigerant gas at high pressure condenses to liquid refrigerant inside the condenser.
Condenser fins lose heat to air flowing through the heat exchanger.
HGV truck air conditioning condenser is often located in front of the coolant radiator.
Road dust and dirt may restrict air flow through the condenser reducing air conditioning system efficiency.
Oily residue on the condenser may indicate a refrigerant leak which could lose compressor lubrication causing the air conditioning compressor to fail.
Several methods may be used to detect truck refrigerant leaks which must be fixed before the air conditioning system can be regassed
Fitting of a new air conditioning condenser will first require safe recovery of any remaining refrigerant.
The TXV meters refrigerant in to the evaporator during air conditioning operation.
A blocked txv can be caused by debris inside the ac system which will affect refrigerant pressures.
A sticking txv may result in the compressor flooding with liquid refrigerant causing failure.
Faulty txv may cause the vaporator to freeze up and block with ice.
The truck air conditioning evaporator is the heat exchanger often located behind the cab dashboard and
will very often require disaassembly of the dash to access.
Evaporator temperature may be regulated by a thermostatic control unit.
Thermostat faults may cause the evaporator to freeze up.
The cab blower fans move cab air across the evaporator fins which remove heat from the air causing the air blown from
dash vents to feel cool.
Best air conditioner operation is acheived by turning the thermostat to cool, and setting dash blower vents to recirculation mode.
The air conditioning system receiver dryer contains a dessicant pack and acts as a filter to remove moisture from the air conditioning refrigerant.
The Receiver dryer change should be changed at manufacturers recommended service interval or if the ac system is disassembled for maintenance.
There are various methods of leak testing truck air conditioning systems.
Oxygen free Nitrogen is charged in to the air conditioning system then locked off to perform a system tightness check.
Drop in pressure will indicate presence of a leak.
Following refrigerant recovery, the truck air conditioner system is put in to vacuum and locked off.
Vacuum guage micron reading change will indicate that the system is leaking.
UV dye is introduced into the air conditioning refrigerant system. A leak may be indicated by a glow while inspecting the system under uv light.
Refrigerant leaks may be detected using an electronic leak detection tool which 'sniffs' the refrigerant.
Air conditioning inspection and diagnosis may involve:
Measuring vent temperatures
Checking high and low side refrigerant pressures during operation.
Ambient temperature checks.
Recovery, weighing, and recharge of refrigerant.
We welcome air conditioning enquiries from fleet operators from a single unit to multi vehicle operations.