Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
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be adjusted at installation to provide the required ventilation air flow. The motorized
damper operates by an external relay with a choice of 24, 120, or 240V coils, to
regulate fresh air ventilation in response to a control located remotely from the heat
pump or air conditioner. The two motorized damper ventilation option includes the
ventilation intake air mover and a fan speed controller for the air mover.
This PowerVent ventilation module features a motorized damper, as above, plus
powered exhaust ventilation to provide up to 450 cfm of outside air. The damper
position can be adjusted at installation to provide the required ventilation air flow.
The PowerVent option includes both a ventilation air intake air mover and an
exhaust air mover. A single fan speed controller that controls both air movers is
standard. An exhaust air fan speed controller is available as an option. This speed
controller regulates the exhaust air motor and allows separate control of the exhaust
air. Independent control allows positive pressurization of the classroom, i.e., more
outside air can be brought into the classroom than what is exhausted.
The fresh air door is opened and closed by the motorized drive. Calibration, as
shown in Figure 10, will ensure the required amount of air, up to a maximum of 450
CFM, is delivered to the classroom.
Follow the directions in Figure 11 to ensure the proper air flow rate setting. After
calibrating the ventilation system, replace the lower front cabinet panel.
Figure 10. Manual Fresh Air System Calibration Procedure
A
B
Manual Settings
20 - 50 CFM
160 CFM
230 CFM
285 CFM
325 CFM
355 CFM
380 CFM
FULL OPEN
420-450 CFM
Note: Once calibrated, the manual fresh air system
door remains at the set opening at all times.
Inside the lower section, locate the circular calibration plates
as noted in the drawing (“A” is fixed, “B” is movable). Remove
the screw shown by the arrow from “Manual Settings.”
Rotate plate B in a clockwise direction until the hole from
which the screw was removed aligns with the hole adjacent
to the desired air flow rate, in CFM.
Reinsert the screw into the hole in plate B and firmly drive
the screw through the appropriate air flow rate hole, so plate
B is securely fastened at the desired opening.
