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Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
1.11 ELECTRICAL, CONDENSATE AND WET HEAT HOOK-UPS
WARNING
ALL ELECTRICAL, PLUMBING, AND REFRIGERATION WORK MUST MEET THE
REQUIREMENTS OF LOCAL AND NATIONAL CODES AND ORDINANCES. WORK
SHOULD BE DONE ONLY BY PROFESSIONALLY QUALIFIED AND TRAINED SERVICE
PEOPLE.
IMPORTANT
STUBOUTS SHOULD BE LOCATED (FROM THE FLOOR OR WALL) TO BE DIRECTLY
OPPOSITE THE SELECTED CABINET KNOCKOUT ON THE CABINET, AS SHOWN IN
FIGURE 3. THIS IS A REQUIREMENT IF A BASE STAND IS TO BE INSTALLED
AND STUBOUTS ARE COMING THROUGH THE FLOOR.
A. 1. For line voltage wiring, the power supply must have the correct voltage, phase
and ampacity for the selected Scholar III™ unit. Check the data label on each
Scholar III unit to determine these values.
Be sure that the power to the line voltage wiring is off prior to hooking-up the
wiring within the Scholar III™ cabinet. Remove the lower front panel for access
to the disconnect. Figure 5 illustrates the disconnect location with the lower front
panel removed.
Turn the disconnect to “OFF” position.
The electrical control compartment is located behind the front door at the lower
right hand corner of the unit. The electrical schematic for the heat pump or air
conditioner is contained in a pocket on the inside of the middle front panel door.
Figure 6 shows typical control centers for the Scholar III heat pump and air
conditioner. Figures 7 and 8 show typical single and three phase wiring diagrams
for the Scholar III heat pump and air conditioner.
2. Power supply service must be with the allowable voltage range stamped on the
identification plate.
To operate a nominal 230/208V model on 208V, change
the transformer line tap from 240V to 208V, following the instructions on
the electrical schematic.
3. Connect the main power wires coming into the cabinet to the input side of the
disconnect. (L1 and L2 for single phase units and L1, L2 and L3 for three phase
models.) Install the ground wire on the ground lug.
CAUTION
THIS SYSTEM CONTAINS COMPONENTS THAT REQUIRE PHASING FOR CORRECT
ROTATION. FAILURE TO OBSERVE ROTATION AND CORRECT ON START-UP WILL
CAUSE DAMAGE NOT COVERED BY THE MARVAIR
®
WARRANTY.
Scroll compressors, like several other types of compressors, will only compress
in one rotational direction. The direction of rotation is not an issue with single-
phase compressors since they will always start and run in the proper direction.
However, three phase compressors will rotate in either direction depending upon
phasing of power. Since there is a 50-50 chance of connecting power in such
a way as to cause rotation in the reverse direction, it is imperative to confirm
that the compressor is rotating in the proper direction at the initial field start-
up of the system. Verification of proper rotation is made by observing that the