Mobile service and repair of tractor cab air conditioning systems on farm for the Agricultural industry
Tractor 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
Cab air conditioning cools and chills tractor cab interior temperature to aid tractor driver comfort during field and harvest operations.
Large tractor cab glass area aids visibility but heat from sunlight radiation through glass may raise in cab and operator temperatures to unbearable hot when doors and windows remain closed to reduce noise and dust levels.
Engine and driveline heat further increase cab and operator temperature.
The clean filtered air provided by the tractor air conditioner improves the working environment in the tractor cab by reducing temperature and removing dusts and pollen.
Air conditioning systems require periodic servicing. R134a refrigerant is often used in tractor air conditioning systems.
R134a is a HFC refrigerant with global warming potential (gwp) of 1430 requiring recovery by FGAS certified personnel prior to disassembly of a tractor aircon system.
We have facilities to recover R134a refrigerant from tractor air conditioners and regas.
The tractor aircon compressor is normally belt driven via auxilliary belt from the crankshaft pulley.
An electromegnetic clutch operates to engage or disengage compressor drive.
When the air conditioner is operating the aircon compressor sucks in refrigerant gas at low pressure and discharges gas at high pressure.
Increase of refrigerant gas pressure also increases refrigerant temperature.
Low refrigerant charge presssure or too high refrigerant pressure may prevent the compressor from operating.
Air conditioning compressor clutch engagement is electrically controlled.
The air conditioner electrical system will be fitted with an evaporator temperature control thermostat, also high pressure and low pressure cut out switches to monitor refrigerant pressure.
Control relays will swich in blower and condenser fan motors and compressor clutch.
During tractor air condtioning operation refrigerant gas at high pressure is pumped into the condenser then
changes state, to liquid refrigerant during the condensation process.
The tractor air conditioning condenser acts as a heat exchanger to lose heat from refrigerant to air passing over the condenser fins.
The tractor air conditioning condenser on most machines is located in front of the radiator and can easily become blocked with dirt, dust and chaff from farm operations.
Restricted air flow through the air conditioning condenser fins will reduce air conditioning system efficiency.
On some vehicle R134a systems refrigerant leakage from the condenser may be noticed by accumulation of a damp oily residue when refrigeration oil is lost.
The TXV is fitted just before the evaporator.
Liquid rferigerant enters the TXV at high pressure and is metered into the evaporator.
The TXV may become blocked by debris if the receiver dryer dessicant pack breaks up.
This will cause excessive system pressure and likely overheating or failure of the compressor.
A sticking txv could cause liquid refrigerant to enter the compressor.
The tractor air conditioning evaporator is the heat exchanger usually located in the roof space above the cab
and will sometimes require cab roof removal to access.
Heat from cab air is removed as it is blown across the fins of the evaporator by cab blower fans.
Evaporator temperature is monitored by a thermostatic switch to prevent freezing.
Moisture and dust can build up on the evaporator coils which may lead to a breeding ground for bacteria.
Air at ambient temperature is drawn in to the tractor cab through cab pollen filters by electric blower fans and moved across the evaporator where heat is removed from the air allowing a cool chilled airflow from cab vents.
The air con system receiver dryer functions to remove moisture from the ac system.
Replacement of receiver dryer should be carried out at manufacturers recommended service interval.
Renewal of the air conditioning receiver dryer is recommended following any maintenance operation involving disassembly of refrigerant circuit components.
for example, whenever a compressor, pipework, or aircon heat exchanger is replaced, or
Refrigerant leak testing of tractor air conditioning system may be accomplished by different methods such as OFN pressure test, electronic refrigerant sniffer, Ultraviolet dye , or leak detection spray.:
A Nitrogen pressure test should be carried out to check for leaks after fitting new
tractor air conditioning system components before refrigerant is added.
An empty air conditioning system is pressurised with Nitrogen gas then locked off whilst under pressure,
Pressure loss will indicate presence of a leak which may be detected using leak detection spray.
Following system evacuation, a vacuum decay hold test is advised prior to regas.
The air conditioning system is locked off whilst under Vacuum and monitored using vacuum guage for any rises in pressure indicating ingress of air.
Specialist ultraviolet dye is added to the air conditioning system, leakage can be detected by shining an ultraviolet light over suspect area.
An electronic leak detector can be used to detect presence of refrigerant gas leaks.
Tractor air conditioning operational checks of refrigerant pressures and vent temperature can be carried out after regas then final system leak checks.
We welcome tractor combine crop sprayer and telehandler air conditioning enquiries.