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ICE CFA1012A I&O Manual 01/2021 New
1.5 General Operation
Refrigerant Cycle (Cooling Mode)
The CFA1012A uses R-410A refrigerant in a conventional vapor-compression refrigeration cycle to
transfer heat from air in an enclosed space to the outside. A supply blower assembly pulls indoor air
across the evaporator. Liquid refrigerant passing through the evaporator is boiled into gas by heat removed
from the air. The warmed refrigerant gas enters the compressor where its temperature and pressure are
increased. The hot refrigerant gas condenses to liquid as heat is transferred to outdoor air drawn across the
condenser by the condenser fan. Liquid refrigerant is expanded into the evaporator through the metering
device to repeat the cycle.
Cooling Mode
: The compressor and condenser fan are energized with a contactor controlled by a 24 VAC
pilot signal (see Figures 2a and 2b). The outside fan or blower motor is controlled by the head pressure
control (see head pressure control, section 1.7). The supply air blowers are energized by the blower relay.
Heating Mode
: A wall-mounted thermostat controls the heating cycle of models which incorporate
resistance heating elements. On a call for heat, the thermostat closes the heat relay to energize the indoor
blower and the resistance elements.
