Greenheck ERCH-20 Installation, Operation And Maintenance Manual page 7

Split DX
The unit is equipped with an evaporator coil that
will be connected to a separate condensing unit
(provided by others). Depending on controlling options,
the condensing unit will be controlled by others or
an integral unit microprocessor controller. Piping
components such as thermostatic expansion valve, filter
drier, sight glass, etc., shall be field-provided.
Heat Pump Module
Units with an optional, integral heat pump module
contains hermetic scroll-type compressor(s), a coaxial
refrigerant-to-water heat exchanger(s), refrigerant flow
reversing valve(s), expansion valve(s), liquid line filter
drier, high pressure manual reset cutout, crankcase
heater(s) and various sensors, service ports and safety
devices. The heat pump is intended to be connected to
an external water source such as a water cooling tower,
boiler, or a geothermal source. The module is piped
to the airside coil located in the supply airstream and
optionally to a reheat coil that will control humidity. The
location of components in the module will vary.
Control circuitry and the
Unit Protection Module
(UPM) for the heat pump
will be provided by the
factory. The UPM is a
printed circuit board and
has LED fault indicator
lights to indicate various
alarm conditions and also
power status. A unit-
specific schematic for
electrical circuits is located in the control center and
another unit-specific schematic for heat pump circuitry
and UPM are located in the heat pump module.
High Efficiency
Scroll Type
Compressors
Coaxial
Refrigerant-
to-Water Heat
Exchangers
Heat Pump Module
®
Unit Protection Module
(UPM)
Refrigerant
Reversing
Valves
Water Intake
and Discharge
Connections
Electric Post-Heaters
The optional post-heater is used as a heat source for
the building and is integrated into the supply airstream.
A temperature sensor (with a field-adjustable set point)
is mounted in the supply airstream after the post-heater
to turn the post-heater on. A SCR heater allows for
an infinite amount of modulating control of the heat to
provide an accurate discharge temperature during the
call for heat.
As standard, the post-heater control panel is not single
point wired to the unit control center. Separate power
must be supplied to the post-heater disconnect (located
in unit control center). Electric heaters are available in
208, 230, 460, or 575 VAC (refer to heater nameplate for
voltage).
Indirect Gas Furnace
An optional indirect gas
furnace may be installed and
provides supplementary heat
to the building. Refer to the
PVF/PVG Indirect Gas-Fired
Heat manuals provided with
the unit. A unit-specific wiring
diagram is located inside the
furnace housing access door.
Outdoor Air Weatherhood
Outdoor air weatherhood will be factory-mounted.
Exhaust Air Weatherhood
The exhaust weatherhood is shipped separately as a
kit with its own instructions. Backdraft dampers are
always included as an integral part of the exhaust hood
assemblies.
Energy Recovery Ventilator with Heating and Cooling General Description - NOT model specific 5