Classic HVPA & HVPSA M&S 8.09-1
15700 - 3
HVAC Equipment
SECTION 15700
HEATING, VENTILATING AND AIR CONDITIONING EQUIPMENT
The purpose of this manual is to provide instructions for maintenance and service for the
Marvair
®
Classic™ series of heat pumps. In addition to this manual, there are other pieces of
literature available from Marvair. The Product Manual covers the installation of the unit and
various accessories and the initial start-up of the unit. An overview of the product line can be
found in the Classic Product Data Sheets. The current version of this literature can be found
and downloaded from the Marvair website at www.marvair.com.
To minimize sound levels within the classroom, certain options should be selected. These op-
tions are designated by throughout the guideline.
1.1 GENERAL OPERATION
A. Classic™ heat pumps are designed to provide quiet comfort to the classroom.
In cooling mode, the compressor will cycle on to provide the cooling required. The
system provides cooling, dehumidification and air circulation.
In heating mode the compressor (heat pump only) will cycle on to provide the
heating required. The system provides heating and air circulation. At lower outdoor
temperatures, additional heating capacity may be provided by an optional electric
resistance heater.
Ventilation air may be provided by the manual or motorized fresh air vent, power
vent or GreenWheel
®
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 ERV provides tempered outside air.
Control systems are either a remote external thermostat, internal thermostat, or a
direct digital control interfacing with the building automation system (BAS).
Hot Gas Reheat (HGR) Dehumidification (Option). To provide on demand
dehumidification, the Classic™ heat pump can 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. Hot gas reheat is available with
motorized fresh air, PowerVent and GreenWheel
®
ventilation systems.
Marvair
®
recommends that for optimum performance, hot gas reheat be used in
conjunction with the GreenWheel
®
heat recovery ventilator. When used with other
ventilation options, hot gas reheat may not maintain satisfactory control of the
humidity in the classroom over all outdoor conditions.
