Specifications
IM 1060-3 / Page 29 of 32
Typical Heating Refrigeration Cycle – Dual 
Compressors
Note:  Typical temperature readings are at full load 
conditions at ISO-13256 for boiler-tower applications.
When the wall thermostat calls for HEATING, the reversing 
valve(energized)directstheowoftherefrigerant,ahotgas,
from the compressor to the air-to-refrigerant heat exchanger 
coil (condenser). There, the heat is removed by the air passing 
over the surfaces of the coil and the hot gas condenses and 
becomesaliquid.Theliquidthenowsthroughathermal
expansion valve to the water-to-refrigerant heat exchanger 
(evaporator). The liquid then evaporates and becomes a 
gas, at the same time absorbing heat and cooling the water. 
Therefrigerantthenowsasalowpressuregasthroughthe
reversing valve and back to the suction side of the compressor 
to complete the cycle.
Figure 34: Heating Refrigeration Cycle










