... easy for maintenance.4. World famous brand compressor,4-way valve,motor,PCB,heat exchanger,Emerson ALCO expansion valve used ... are available,R22,R407C,R410a,R417A,R134A are for optional. Commercial type heat pump(High Temp.) ... cycle of defrosting, Power lost memoryDefrostingTypeAutomatic 4 Way Valve ReverseHeatingCrankshaft heater, Bottom heater, Evaporator heaterProtection functionCompressor overload ...