Sequence Of Operation - Greenheck APEX-200 Installation, Operation & Maintenance Manual

Sequence of Operation

Basic Unit
The APEX unit is pre-wired such that when a call for outside air is made (via field supplied 24 VAC control
signal wired to unit control center), the supply fan, exhaust fan and energy wheel are energized and the
motorized dampers open. The APEX unit can be supplied with or without heating and cooling coils. For units
with coils, controls can be supplied by Greenheck (refer to the Temperature Control IOM, Part #461468, for
sequence of operation) or by the controls contractor. If supplied by the controls contractor, they would provide,
mount, and wire any temperature controllers and temperature or relative humidity sensors required for the unit
to discharge air at the desired conditions.
Summer Operation
Outdoor air is preconditioned (temperature and moisture levels are decreased) by the transfer of energy from
the cooler, drier exhaust air via the energy recovery wheel.
Units supplied with cooling coils can further cool the air coming off the wheel and strip out moisture to levels at
or below room design. A heating coil downstream of the cooling coil can reheat the air to a more comfortable
discharge temperature to the space.
Economizer Operation: See Economizer Application/Operation section
Winter Operation
Outdoor air is preconditioned (temperature and moisture levels are increased) by the transfer of energy from the
warmer, more humid exhaust air via the energy recovery wheel.
Units supplied with heating coils can further heat the air coming off the wheel to levels at or above room
design.
Frost Control Operation: See Frost Control Application/Operation section
25
®