General Operation - Industrial Climate Engineering SlimPac ECUA12 Installation & Operation Manual

1.5

General Operation

Refrigerant Cycle (Cooling Mode)
The SlimPac™ 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.
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ICE SlimPac ECUA12-18 I&O Manual 03/2019 Rev.2