HGV Truck Mobile Air Conditioning Service Shropshire & Mid Wales

Regas / Repair of HGV Lorry Air Conditioning Systems

Truck Air Conditioning Mobile Service covers Shrewsbury, Oswestry, Telford, Shropshire and Welshpool Mid Wales areas.

Telephone 07703 558610 www.autoelectrics.net

HGV Truck Air Conditioning Benefits

Sunlight radiation on cab glass combined with heat from the truck engine can cause in cab temperatures to soar during summer months. Dry weather increases airborne dusts and pollen.

Correctly functioning truck cab air conditioning benefits both driver and fleet transport operator.

Cool lorry cab interior temperature gives drivers a comfortable working environment keeping drivers alert and reducing accident risk.

Air drawn into the cab air conditioning system passes through the cab pollen filter reducing road dust and particulates entering the cab.

The truck air conditioner recirculates clean filtered cab interior air allowing windows to remain closed providing increased security.

HGV Truck air conditioning refrigerant and legal compliance

Most 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.

Commercial Vehicle Refrigerant Recovery

HFC refrigerant (including R134a) is proven to cause environmental damage if released to atmosphere. where air conditioning and refrigeration systems contain hfc refrigerants it is illegal for persons to just undo pipes and let refrigerant go .
We have FGAS certification and facilities to recover R134a from lorry air conditioning systems on site.

Truck Air Conditioner Regas

We operate a mobile service to enable truck cab air conditioning systems to be regassed at your premises. Any regas work will be subject to the air conditioning system passing pressure tests.

How Much Refrigerant?

Refrigerant recharge quantity can be looked up on vehicle manufacturers data or may be printed on a label on the vehicle. Most UK spec truck cab air conditioning systems require R134a refrigerant charge quantities in the range between 900 grams to 1600 grams

Truck Air Conditioning System Components

Receiver Dryer / Suction Filter

The air conditioning system receiver dryer is a service component providing moisture removal and filtration. The dryer contains a dessicant pack acting as a filter to remove moisture and contaminants 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.

Refrigerant hoses and pipework

Flexible refrigerant hoses and metal pipework convey refrigerant around the air conditioning system. Connections where O-rings are fitted can be prone to refrigerant leakage as O-rings deteriorate.

Truck Air Conditioning Compressor

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 air conditioning system operation the ac compressor pumps refrigerant around the system by suction intake of refrigerant gas at low pressure and discharge of gas at high pressure.
Increase of gas pressure also increases temperature.
Pressure switches may prevent the aircon compressor may not operate if the refrigerant pressure is too low.
Electrical faults can affect compressor clutch engagement.
Refrigerant oils are added to vehicle air conditioning systems during regas.
Loss of refrigerant due to system leak may result in premature compressor failure.

Changing the truck air conditioning compressor will first require safe recovery of air conditioning refrigerant

Truck Air Conditioning Condenser

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.

Truck air conditioning Thermostatic Expansion Valve TXV

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.

Truck Air Conditioning Evaporator

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.

Controls and Sensors

Drivers controls enable off/on, blower fan speed, temperature, and recirculation modes to be selected.
Pressure switches are fitted to the refrigerant circuit to detect low and high refrigerant pressure.
Temperature sensor is fitted to sense evaporator temperature.

Truck Cab Blower Fans

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.

How to set air conditioning controls for best cooling effect

Best air conditioner operation is achieved by:
Turning the thermostat control to coldest setting
Setting dash blower vents to recirculation mode
Switching fan to full speed

Truck Air Conditioner System Leak Tests

There are various methods of leak testing truck air conditioning systems.

OFN Pressure Test

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.

Vacuum Decay Test

Following refrigerant recovery, the truck air conditioner system is put in to vacuum and locked off.
Vacuum gauge micron reading change will indicate that the system is leaking.

UV Leak detection

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.

Electronic Leak Detector

Refrigerant leaks may be detected using an electronic leak detection tool which 'sniffs' the refrigerant.

Truck air conditioning operational checks

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.