Scholar V VAIVA Maintenance & Service Manual 10/2017 Rev.2
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1.1 GENERAL OPERATION
A. Scholar V heat pumps and air conditioners are designed to provide quiet comfort to
the classroom.
In cooling mode, the compressor will modulate its speed to match the cooling
requirements of the room. The system provides cooling, dehumidification and air
circulation.
In heating mode the compressor (heat pump only) will modulate its speed to
match the heating requirements of the room. The system provides heating and
air circulation. At lower outdoor temperatures, additional heating capacity may be
provided by an optional electric resistance heater or a hot water/steam coil.
Ventilation air may be provided by the manual or motorized fresh air vent, power
vent, GreenWheel
®
ERV or GreenCube
®
ERV. These ventilation systems operate
when there is a call for cooling or heating or independently to provide fresh air.
Note that with the manual, motorized fresh air vent and the power vent options, if
the compressor is not operating and the indoor blower is running, unconditioned
outside air is being introduced into the classroom. The GreenWheel and GreenCube
ERV dehumidify and cool the outside air in the summer. They humidify and heat the
outside air during the winter.
Temperature and Humidity are monitored by transmitters which may be wall mounted
or mounted in the return air stream. Setpoints are adjusted with a Human Machine
Interface (HMI) screen provided as standard with the unit or with an optional Building
Automation Interface which allows connection with a customer provided Building
Automation System (BAS).
Hot Gas Reheat (HGR) Dehumidification. To provide on demand dehumidification, the
Scholar V heat pump or air conditioner have a factory installed hot gas reheat coil to
allow dehumidification through continued cooling with discharge air reheated to avoid
over cooling the classroom. The operation of the HGR is controlled by a three-way
heat reclaim valve. The HGR coil is sized to provide a heating capacity approximately
equal to the sensible capacity of the unit When the demand for cooling is satisfied
and the humidity controller calls for dehumidification, hot gas is directed to a reheat
coil downstream from the evaporator coil to add heat to the dehumidified, chilled air
supplied to the classroom.
