Cooling is provided by a compression/expansion refrigeration system using refrigerant R134-A with all metal tubing (no rubber hoses). Heating is provided by using the machine's engine coolant, engine oil or hydraulic fluid. The entire heating circuit is metal tubing (no rubber hoses). Power for the compressor and the fan shaft, which turns the condenser fan and the evaporator blower, is from a single hydraulic motor. At full load, the motor requires 10 GPM at 1300 PSI pressure drop, constant volume, variable pressure. Motor pressure drop is 600 PSI when the system compressor is off and only the fans are running. No electric motors are used.
Supporting a capacity of 24,000 BTU's/Hr., (2 tons), the blower delivers 800 CFM of conditioned air which circulates a windstorm throughout the cab providing outstanding air distribution and comfort for all occupants. The condenser fan delivers 1000 CFM across a generous and filtered condenser surface which delivers full rated capacity up to 115° F outside air temperature.
Pressurization of the cab is an inherent feature of the MacBone design, wherein the 800-CFM blower takes 10% outside air for 80 CFM of forced ventilation and basic pressurization, which keeps dust from entering the cab.