1.8 Electrical Operation - Ice ECUA90 Installation & Operation Manual

Fresh Air Damper
Allows introduction of outside air into the building to provide positive pressurization. Field installed
on either the left or right hand side of the unit.
Dual Compressors With Lead/Lag Operation
Freeze Sensor On Indoor Coil
Prevents frost on the indoor coil caused by a loss of air flow or restrictive duct work. Field installed.
Filter Access From Return Air Grille
Factory or field installed filter bracket allows changing and access to the filters from the return air grille.
See model ID, special option code "I".
Reverse Air Flow Configuration
Location of Supply and Return Air Openings are reversed.

1.8 Electrical Operation

The compressor and condenser fan are energized with a contactor controlled by a 24 VAC pilot signal.
Some compressors incorporate an internal PTC crankcase heater that functions as long as primary power
is available. The heater drives liquid refrigerant from the crankcase and prevents loss of lubrication
caused by oil dilution. Power must be applied to the unit for 24 hours before starting the compressor.
The condenser (outside fan) motor is energized by the same contactor.
The indoor evaporator fan motor is controlled by the fan purge on the electronic control board.
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ECU 04/2015 rev.3