Greenheck Fan 45 Patio Heater User Manual


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The energy recovery wheel operation can be altered to take advantage of economizer operation (free cooling).
Twomodesareavailable:1)De-energizingthewheelor2)Modulatingthewheel.Afieldsuppliedcallforcool
(Y1) is required.
De-energizing the wheel is accomplished with a signal from a Temperature or Enthalpy sensor mounted in
the supply air inlet compartment. This Primary sensor will de-energize the energy wheel when the outdoor air
temperature (factory default is 65ºF) or enthalpy (factory default is the “D” setting) is below the field adjustable
set point. An Override temperature sensor is also furnished in the supply air inlet compartment to deactivate
economizer mode. The Override (with field adjustable set point) is set at some temperature lower than the
Primary sensor (factory default is 50ºF). Effectively, the two sensors create a deadband where the energy
recovery wheel will not operate and free cooling from outside can be brought into the building unconditioned.
Testing
Temperature Sensor with Override
• TurnbothTemperatureandOverridethermostatsdownaslowastheygo.The
wheel should be rotating.
• TurntheTemperaturesensorupashighasitgoes,andkeeptheOverridesensor
as low as it will go. The wheel should stop rotating.
• Turnbothsensorsashighastheywillgo.Thewheelshouldstartrotating.
• SettheTemperaturesensoratdesiredpointforeconomizeroperationtobegin.
Set the Override sensor at desired point for economizer operation to end (factory
default is 65ºF and 50ºF, respectively).
Enthalpy Sensor with Override
• Turnunitpoweroff.DisconnectC7400solidstateenthalpysensorfromterminal
So on the enthalpy controller. Also, disconnect the 620 ohm resistor from
terminal Sr on the enthalpy controller. Turn unit power on. The LED on the
enthalpy controller should light and the energy recovery wheel should not rotate.
• Turnunitpoweroff.Reconnect620ohmresistortoterminalSrontheenthalpy
controller. Turn unit power on. The LED on the enthalpy controller should not
light and the energy recovery wheel should energize and rotate.
If the steps above provide the results described, the enthalpy
economizer is working properly.
• Turnunitpoweroff.ReconnectC7400solidstateenthalpysensor
to terminal So.
Modulating the Wheel
In applications in which an internal heat gain is present in the space,
the rotational speed of the energy wheel may be modulated (via variable
frequency drive) to avoid overheating the space during the winter. The speed of the energy wheel will be
controlled in response to the discharge temperature setpoint.
SequenceofOperation:
The variable frequency drive is fully programmed at the factory (refer to VFD section
for more information). A “call for cool” must be field wired to the unit (terminals provided in unit - refer to wiring
diagram in unit control center) to allow for initiation of economizer mode. When the space calls for cooling,
factorysuppliedcontrolswilldrivethefollowingwheeloperations:
T
OA
> T
RA
: Wheelrunsatfullspeed(maximumenergyrecovery)
T
OA
< T
RA
and T
OA
> T
SA
: Wheelisstopped(noenergyrecovery)
T
OA
< T
RA
and T
OA
< T
SA
: Wheelwillmodulatetomaintaindischargetemperature
where (T
OA
) is the outdoor air temperature set point, (T
RA
) is the return air temperature set point, and (T
SA
) is
the supply air discharge thermostat setpoint (nominal 60¡F Ð not adjustable).
Economizer Application/Operation
Temperature Sensor
with Override
Enthalpy Sensor
with Override
Enthalpy
Controller
OPTIONAL ACCESSORIES
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