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Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
5. The
direct digital control
(DDC) interfaces with the building automation
system (BAS) is to be defined by the specifier, in consultation with the Marvair
®
sales representative. Marvair will factory install the
DDC
sent by the DDC
manufacturer, and purchased by the customer.
B. Thermostats for air conditioners or heat pumps with only one stage of heating.
1.
Digital, non-programmable thermostat.
1 stage heat, 1 stage cool. Fan switch:
Auto & On. Manual changeover system switch: Cool-Off-Heat. Low temperature
protection. °F or °C selectable. Thirty minute power loss memory retention. For
use with models VAIA only. Marvair P/N 50121.
2.
Digital, seven day programmable thermostat.
1 stage heat, 1 stage cool.
Fan switch: Auto & On. Auto changeover. Keypad lockout. Non-volatile program
memory. Title 24 compliant. For use with models VAIA only. Marvair P/N 50123.
3.
Digital, non-programmable thermostat.
One stage cool/One stage heat.
Manual or auto changeover. Fan mode: Auto or On. Permanent retention of
settings upon power loss. Field adjustable temperature calibration. Max heat and
minimum cool set points. Adjustable temperature differential. Remote sensor
capable. Keypad lock out. Status LED. °F or °C selectable. For use with models
VAIA only. Marvair P/N 50186.
C. Humidity Controller.
All units with Electric reheat or Hot Gas Reheat must have a method of signaling the
reheat function. If a DDC system is not being used, a Humidity Controller must be
installed.
Digital Humidity Controller. Programmable dehumidistat, humidistat and ventilation
control. Time of day can be set for dehumifier, humidifier or ventilation to run. Auto
changeover for humidification or dehumidification. Permanent memory retention
of set points. Humidity sensor can be field calibrated. High & low dehumification
set points. Outdoor temperature and humidity sensor included. ºF or ºC selectable.
Marvair P/N 50254.
D. Thermostat guards
1. Clear thermostat guard with keylock & clear plastic cover & base for 50121,
50123, 50186, 50107 & 50252 thermostats. Marvair P/N 50092.
2. Clear thermostat guard with keylock & clear plastic cover & base for 50248
thermostat. Marvair P/N 50119.
1.04B OPTIONAL CONTROLS
A. All units have the following control options available.
1. The
spring wound timer
is a field installed kit used to enable operation of the
heat pump for up to six hours, or override the building automation system. (p/n
08557)
2. The
hard start kit
is field installed and used on single phase power models
to overcome hard starting conditions. Note: Hard start kits are generally not
recommended for use on scroll compressors.
3. The
motorized fresh air damper with PowerVent and GreenWheel®
ERV
ventilation options can be equipped with an exhaust fan air speed control, which
controls the ventilation exhaust blower independent of the fresh air intake blower.
