The MacBone C Series Rooftop 24,000 BTU/hr air conditioning unit is an overhead mounted, unitary, or self-contained unit, with a closed, precharged refrigeration circuit, driven by a single, integral, hydraulic motor. Heating is derived from the circulation of hot engine coolant, engine oil or hydraulic oil through the unit. Heating capacity is 30,000 BTU/hr at a fluid flow rate of 1.5 GPM at 140° F. The design concept is derived from the need for an air conditioning unit for industrial applications where the unit can be quickly removed for service without involving the sealed refrigeration circuit. Cooling is provided by a thermostatically controlled automotive type compressor, using R-134A refrigerant. The condenser fan and evaporator blower share a common shaft, driven by the hydraulic motor with sufficient power to produce substantial condenser air flow, even with a filter on the outside coil, thus insuring reliable performance even in a heavily dust laden environment. Substantial power delivered to the inside air blower also assures delivery of full system capacity under all conditions. Induction of 10% outside air provides cab pressurization to exclude dust and other contaminants from entering the cab environment.
Hydraulic drive input is usually, but not necessarily, from a pump driven by the vehicle's engine and utilizing the vehicle's hydraulic reservoir. Required flow is a constant 10 GPM at a variable pressure from 600 to 1400 PSIG. System pressure relief, provided by the installer, should be set at 1650 PSI. Electrical input of 3.5 amps, at 12 or 24 VDC, is used only to activate the compressor clutch.
All units utilize non-CFC, R-134A refrigerant, measure 36 1/2 x 24 1/2 x 12 1/2 inches high and weigh 175 pounds. Hydraulic lines are #8, supply and return, up to 40 feet. The motor has an external case drain to protect its shaft seal. Four 1/2 inch SAE mounting bolts provide for quick removal for service or replacement. The dual V belt drive system has an automatic tensioner and operates in a closed, ventilated area. Recommended operating time before overhaul is 6000 hours. Recommended unit life is four overhaul cycles. Note, however, that we are finding units with up to 6000 hours in need of drive belts only. We also note that four overhaul cycles may not be the limit.