Marvair Scholar III VAISA Instructions and recipes

Scholar III™
Heat Pump & Air Conditioner
(CSI 15740)
Model VAISA
2, 2.5, 3, 3.5, 4 & 5 Tons
INSTALLATION AND
START-UP
Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
P/N 01564
MODEL NO.: ______________________ SERIAL NO.: _________________
DATE OF START-UP.:_______________
Scholar III™
WARNING
SAFETY REQUIREMENTS
• If the information in these instructions
are not followed exactly, a re may result
causing property damage, personal injury or
loss of life.
• Read all instructions carefully prior to
beginning the installation. Do not begin
installation if you do not understand any of
the instructions.
• Improper installation, adjustment, alteration,
service or maintenance can cause property
damage, personal injury or loss of life.
• Installation and service must be performed
by a qualied installer or service agency in
accordance with these instructions and in
compliance with all codes and requirements
of authorities having jurisdiction.
• Follow all safety codes.
Manufactured By:
Marvair Division of the AIRXCEL®Commercial Group
P.O. Box 400 • Cordele, Georgia 31010 • 156 Seedling Drive • Cordele, Georgia 31015
[phone] • Fax [phone]
www.Marvair.com | www.EubankWallmount.com
The most current version of this manual can be found at www.Marvair.com.

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 2
How To Use This Manual
This manual is intended to be a guide to the Marvair®Scholar III™ line of vertical packaged heat pumps and
air conditioners. This manual covers the installation and start-up of the Scholar III heat pumps and air conditioners,
models VAISA, with two stage compressors. It contains installation, troubleshooting, maintenance, warranty, and
application information. The information contained in this manual is to be used by the installer as a guide only. This
manual does not supersede or circumvent any applicable national or local codes.
If you are installing the Scholar III™ heat pump or air conditioner, rst read the entire manual and Appendices
for any of the options and accessories before beginning the installation. The Appendices describe the installation of
the base stand, the plenum, trim strips, wall brackets and outdoor louvers.
If a malfunction occurs, follow this troubleshooting sequence:
1. Make sure you understand how the Scholar III™ unit works.
2. Identify and correct installation errors.
3. If you are still unable to correct the problem, contact the Factory at 1-800-841-7854 for additional
assistance.
Please read the following “Important Safety Precautions” before beginning any work. Failure to follow
these rules may result in death, serious bodily harm, property damage and damage to the equipment.
Important SafetyPrecautions
1. USE CARE when LIFTING or TRANSPORTING equipment.
2. TRANSPORT the UNIT UPRIGHT. Laying it down on its side may cause oil to leave the compressor, re-
sulting in DAMAGE upon START-UP.
3. TURN ELECTRICAL POWER OFF AT THE breaker or fuse box BEFORE installing or working on the
equipment. LINE VOLTAGES ARE HAZARDOUS or LETHAL.
4. OBSERVE and COMPLY with ALL applicable PLUMBING, ELECTRICAL, and BUILDING CODES &
ordinances.
5. SERVICE may be performed ONLY by QUALIFIED and EXPERIENCED PERSONS.
* Wear safety goggles when servicing the refrigeration circuit
* Beware of hot surfaces on refrigerant circuit components
* Beware of sharp edges on sheet metal components
* Use care when reclaiming or adding refrigerant
6. Use COMMON SENSE - BE SAFETY CONSCIOUS
This is the safety alert symbol . When you see this symbol on the air conditioning unit and in the instruction
manuals be alert to the potential for personal injury. Understand the signal word DANGER, WARNING and
CAUTION. These words are used to identify levels of the seriousness of the hazard.
DANGER Failure to comply will result in death or severe personal injury and/or property damage.
WARNING Failure to comply could result in death or severe personal injury and/or property damage.
CAUTION Failure to comply could result in minor personal injury and/or property damage.
IMPORTANT Used to point out helpful info that will result in improved installation, reliability or
operation.
Specications subject to change without notice.
© 03/2019 Marvair®, Division of AIRXCEL™, Inc.

3 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
SECTION 15700
HEATING, VENTILATING AND AIR CONDITIONING EQUIPMENT
INSTALLATION AND START-UP INSTRUCTIONS
FOR SCHOLAR III™ HEAT PUMP AND AIR CONDITIONER MODEL VAI (15740)
TABLE OF CONTENTS
Article Description Page
1.01 Tools/Field Furnished Supplies ......................................................4
1.02 Inspection/Unpacking/Handling......................................................4
1.03 Standard Controls ..........................................................................7
1.04A Thermostats & Sub-bases..............................................................8
1.04B Optional Controls ...........................................................................9
1.05 Location Selection and Preparation .............................................10
1.06 Power and Control Wiring (Rough-In).......................................... 11
1.07 Condensate Drain Line (Rough-In) ..............................................13
1.08 Wet Heat (Rough-In)....................................................................13
1.09 Preparation of the Scholar III™ Units...........................................13
1.10 Installation Through the Outside Wall ..........................................15
1.11 Electric, Condensate and Wet Heat Hook-ups.............................17
1.12 Ventilation System Calibration .....................................................23
1.13 Control Adjustments.....................................................................25
1.14 Remote Thermostat Installation ...................................................32
1.15 Start-up Procedure.......................................................................34
Appendix A Ratings and Data .........................................................................36
Appendix B Base Stand Installation ................................................................37
Appendix C Free Blow/Plenum Installation......................................................40
Appendix D Trim Strip Installation ...................................................................43
Appendix E Outdoor Louver/Collar Installation................................................45
Appendix F Electric Heater Installation ...........................................................48

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 4
SECTION 15700
HEATING, VENTILATING AND AIR CONDITIONING EQUIPMENT
1.01 TOOLS/FIELD FURNISHED SUPPLIES
WARNING
TO AVOID PERSONAL INJURY, ADEQUATE PROTECTIVE CLOTHING MUST BE WORN
AND PRECAUTIONS IN HANDLING AND INSTALLING THIS EQUIPMENT MUST BE
PRACTICED AT ALL TIMES.
• Power Drill/Driver & Extension
• T25 TORX Bits
• 5/16 hex bit
• Needle Noise Pliers
• Wire Stripper/Cutter
• Spirit Level
• Tape Measure
• Screwdriver with Slotted Bit
• Caulk Gun
• Sealant Caulk (tube)
• Wire Nuts for Power and Control Wiring Gauges
• Supplies to Install PVC Condensate Drain
• Floor Fasteners for Cabinet (4 required for 1/2” pass through holes) - Appropriate
Drivers for Floor Fasteners
• Supplies to Install Wet Heat Coil (Steam or Hot Water) (if appropriate)
• 25 Ft. of Polyurethane Foam Strips, 1” Wide x 1/2” Thick, Adhesive Backing, for
Scholar III/Wall Interface.
1.02 INSPECTION/UNPACKING/HANDLING
A. The Scholar III™ heat pumps and air conditioners are shipped to the job site on 4x4
wood base framing, and enclosed in shrink wrap.
Freeblow and ducted plenums are shipped on wooden skids and enclosed in shrink
wrap.
Outdoor louvers/collar assemblies, louvers and collars are shipped in corrugated
containers.
Base stands are shipped on a wooden skid and are enclosed in shrink wrap.
Trim pieces are enclosed in corrugated carton and strapped to a wooden skid.
B. Immediately upon delivery to the jobsite, each Scholar III™ heat pump or air
conditioner and the appropriate additional accessories should be inspected
for visible and concealed damage. All damage must be reported to the freight
carrier within 15 days, on the freight carrier’s form.
The Scholar III™ heat pump or air conditioner and additional accessories should
be stored inside and not exposed to outdoor weather conditions. Do not remove
equipment from packing until it is ready to be installed.

5 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
WARNING
DO NOT STACK THE UNIT OR ANY ACCESSORIES ON TOP OF ONE ANOTHER.
THE UNITS SHOULD ALWAYS REMAIN IN THE UPRIGHT POSITION WHEN BEING
SHIPPED, STORED, HANDLED OR INSTALLED.
DO NOT STORE THE UNIT OR ACCESSORIES IN OUTDOOR
WEATHER CONDITIONS.
WARNING
THE SCHOLAR III UNIT WEIGHS IN EXCESS OF 1,000 LBS. WHEN MOVING THE
UNIT, SUFFICIENT MANPOWER AND MECHANICAL EQUIPMENT MUST BE USED
TO PREVENT DAMAGE TO THE UNIT AND INJURY TO PEOPLE. TO FACILITATE
MOVING THE SCHOLAR III UNIT, IT MAY BE NECESSARY TO LAY THE UNIT ON ITS
SIDE ON DOLLIES. IF THIS IS REQUIRED, USE TWO DOLLIES AND PLACE THE UNIT
ON ITS RIGHT SIDE (WHEN FACING THE SCHOLAR II UNIT). THE UNIT SHOULD
NOT REMAIN IN THIS POSITION ANY LONGER THAN REQUIRED FOR THE ACTUAL
MOVING PROCESS. IF THE SCHOLAR III UNIT HAS BEEN PLACED ON ITS SIDE, DO
NOT ATTEMPT TO START THE UNIT UNTIL THE UNIT HAS BEEN UPRIGHT FOR AT
LEAST 24 HOURS.
C. Note the unit identication label is located on the right side cabinet panel at the lower
front corner. The identication label has the model and serial number on it and the
type of refrigerant and amount of refrigerant charge.
IMPORTANT
WHEN THE HEAT PUMP OR AIR CONDITIONER IS INSTALLED, MODEL NUMBER AND
SERIAL NUMBERS ARE TO BE RECORDED ON THE COVER OF THIS
MANUAL AND MAINTAINED IN A LOCATION FOR IMMEDIATE ACCESS, WHEN
REQUESTING FURTHER INFORMATION CONCERNING THIS EQUIPMENT.
Serial Number Date Code
A = January E = May J = September D = 2014 P = 2003
B = February F = June K = October E = 2015 R = 2004
C = March G = July L = November F = 2016 S = 2005
D = April H = August M = December G = 2017 T = 2006
H = 2018 U = 2007
I = 2019 V = 2008
J = 2020 Y = 2009
K = 2021 Z = 2010
L = 2000 A = 2011
M = 2001 B = 2012
N = 2002 C = 2013

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 6
Figure 1. General External Component Identication and Access to Scholar III™
Heat Pump or Air Conditioner
RETURN AIR
ONE ON EACH SIDE
REAR CONDENSATE ACCESS
INTAKE & EXHAUST
OF CONDENSER AIR
AND FRESH AIR
OUTDOOR
AIR BOX
For the Scholar III™ heat pump or air conditioner system, the identication
numbering system is shown below. The model identication number is located as
shown in Figure 1.
Source
Vertical
Air
Indoor
Nominal Cooling
System Type
HP = Heat Pump
AC = Air Conditioner
Power Supply
A=208/230V,1,60Hz
C =208/230V,3,60Hz
D= 460V,3,60Hz
Configuration
N= Manual Damper (std)
H=GreenWheel®ERV
B =Motorized Damper
J =Power Vent with
Motorized Damper Special Options
G =Hot Gas Reheat/Dehumidification
•••• •
VAI•III
Configuration
III = Scholar III
2-Stage
Compressor
S
Refrigerant
R-410A
A
24 = 24,000 BTUH
30 = 29,000 BTUH
36 = 34,000 BTUH
40 = 41,500 BTUH
48 = 46,000 BTUH
60 = 54,500 BTUH
Heat – kW
000 - No Heat
050 = 5 kW
075 = 7.5 kW
100 = 10 kW
150 = 15 kW
099 = 99 (Hot Water)
Q=GreenCube™ ERV

7 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
1.03 STANDARD CONTROLS
A. Programmable Logic Controller (PLC) Microprocessor
Scholar IIITM heat pumps and air conditioners use a factory installed PLC
microprocessor to control the operation, the safety switches and function
options. LED’s show operational status and provide assistance with diagnosis if
troubleshooting is ever required. Various control functions are eld selectable. The
PLC is also capable of communicating to PLC’s in other Scholar units to allow run
time leveling and does not require additional equipment installed in the Scholar III
unit. The PLC microprocessor provides improved reliability because of the reduction
of components, the components utilized are more durable and the control box wiring
has been simplied. Pertinent statistical data about the life of the refrigeration system
can be accessed through the PLC.
The PLC microprocessor provides for the following control and operation functions:
• Anti-Short Cycle Timer - Prevents the compressor from destructive short
cycling due to momentary power interruptions. One of three time intervals can
be eld selected.
• Defrost Timer (heat pumps only) - Adjustable defrost control that is based
upon both time and temperature. The time interval is adjustable from 30 to 90
minutes in one minute increments.
• BAS Control Relay - Provides 24 VAC coil to control operation from Building
Automation System (BAS). Note - an additional BAS control relay can be
added when 120 or 240 VAC coils are required.
B. High and Low Refrigerant Pressure and Loss of Charge Switches
These switches render the compressor and outdoor fan motor inoperative whenever
the limits of the pressure switches are exceeded. In the event of high pressure, the
Scholar IIITM heat pump or air conditioner will turn off and lockout.
The low pressure (A/C) and loss of charge (HP) switch is bypassed for 8-1/2 minutes
during each start-up. The system will lockout if the low pressure switch opens three
times within one hour or if it does not reset within 8-1/2 minutes of the Scholar IIITM
heat pump or air conditioner start-up.
The high and low pressure and loss of charge switches are resettable at the wall
thermostat or by turning power off and then on to the Scholar IIITM heat pump or air
conditioner. A fault LED located on the PLC indicates that a lockout has occurred
and whether it is due to high or low refrigerant pressure.
C. Heat Related Controls
The outdoor thermostat (heat pump only), factory set at 40°F, determines the
temperature at which the supplemental electric heat (or wet heat) turns on to heat the
classroom. The temperature set point can be adjusted in the eld for local conditions.
When the outdoor thermostat activates wet heat, the compressor simultaneously turns
off.

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 8
The electric heat control (heat pump only) allows the user to select whether the
electric heat operates simultaneously with the compressor. The units are wired at the
factory for simultaneous operation. For non-simultaneous operation, a wire is moved
from one terminal to another in the control box.
The electric heat during defrost (heat pump only) allows the user to select
whether electric heat operates when the heat pump enters into the defrost mode.
The units are wired at the factory to prevent the electric heaters from operating
during the defrost mode. For operation during defrost, a wire is moved from one
terminal to another in the control box. NOTE: for operation of the electric heat during
defrost, the electric heat control must be congured to allow simultaneous operation
of the electric heat and the compressor.
D. The motorized fresh air damper with PowerVent and GreenWheel® ERV
ventilation options are equipped with a fresh air fan speed control. The fresh air
fan speed control controls both the ventilation intake and exhaust blowers together,
automatically balancing the intake and exhaust cfm up to 450 cfm. An optional fan
speed control allows independent operation of the intake and exhaust air blowers.
IMPORTANT
MINIMUM AIR FLOW IS REQUIRED FOR PROPER OPERATION.
1.04A THERMOSTATS AND SUB-BASES
A. Thermostats for Air Conditioners and Heat Pumps with two stages heating.
1. Digital, 7 day, 5-2 and 5-1-1 day programmable thermostat. Two stage heat/
Two stage cool. Manual or auto changeover. Fan: Auto & On. Permanent
retention of setting on power loss. Field adjustable temperature calibration.
Adjustable max. setpoint for heating and min. adjustable setpoints for cooling.
Adjustable temperature differential. Keypad lockout. Status LED. °F or °C
selectable. Title 24 compliant. For use with models VAIA and VAISA. Marvair P/N
50107.
2. Digital, 7 day, 2 occupied & 2 unoccupied periods for each day of the week
programmable thermostat. Three stage heat/Three stage cool. Manual or auto
changeover. Fan: Auto & On. Ten year retention of programming settings and 48
hour clock and day settings on power loss. Adjustable max. setpoint for heating
and min. adjustable setpoints for cooling. Adjustable temperature differential.
Keypad lockout. Status LED. °F or °C selectable. Optional remote sensors for
outdoor air, supply air and humidity. Title 24 compliant. For use with models VAIA
and VAISA. Marvair P/N 50248.
3. Digital, non-programmable thermostat. Two stage heat/Two stage cool.
Manual or auto changeover. Fan: Auto & On. Permanent retention of setting on
power loss. Field adjustable temperature calibration. Adjustable max. setpoint
for heating and min. adjustable setpoints for cooling. Adjustable temperature
differential. Keypad lockout. Status LED. °F or °C selectable. For use with models
VAIA and VAISA. Marvair P/N 50252.
4. MAR7000 thermostat. See Product Data Sheet for complete description.

9 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 dened by the specier, 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 dehumier, humidier or ventilation to run. Auto
changeover for humidication or dehumidication. Permanent memory retention
of set points. Humidity sensor can be eld calibrated. High & low dehumication
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 eld 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 eld 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.

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 10
1.05 LOCATION SELECTION AND PREPARATION
WARNING
THE SCHOLAR III™ HEAT PUMP AND AIR CONDITIONER MUST BE INSTALLED
IN CONFORMANCE WITH ALL APPLICABLE LOCAL AND NATIONAL ELECTRICAL,
PLUMBING AND BUILDING CODES.
A. The Scholar III™ heat pump and air conditioner must be installed on an outside wall
for access to outside air. The wall opening dimensions are shown in Figure 2. It must
not interfere with any windows or doors to the outside. The outdoor air path must
not be impeded by shrubbery or other obstructions. Do not locate the Scholar III
heat pump or air conditioner where noxious fumes or gas can be drawn in from the
outdoor air and introduced in the classroom.
The Scholar III™ heat pump or air conditioner must be installed on a hard, level,
smooth surface such as concrete, wood or tile. Do not install the unit on a carpeted
surface. Do not locate the either side of the Scholar within 12” from a wall. The front
doors swing open to allow access to all components. Do not put anything immovable
in front of the Scholar III unit
To remove carpet from where the “footprint” of the unit will be, when installed,
carefully measure, cut and remove carpet from an area based on the dimensions of
the Scholar III cabinet as described in Figure 3; and allowing for any offset or standoff
from the nished interior surface of the wall.
Prior to installation of the Scholar III™ heat pump or air conditioner, provisions are to
be made for the following, as appropriate.
1. Wall opening dimensions for the Scholar III™ heat pump and air conditioner
are as shown in Figure 2. The unit is designed for installation through a 14 inch
thickness nished wall. For nished wall depth less than 14 inches, the unit will
stand off from the interior nished wall and it will be necessary to order and install
trim pieces to provide a nished, color coordinated enclosure that ts ush to the
interior wall.
Figure 2. Wall Opening Dimensions for Scholar III™ Heat Pump and Air Conditioner.
DIMENSION
A 45-1/8”
B 48”
C 32”
C* 34”
*When 2”high base stand is used, the C* dimension
is specied. The use of a base stand with a height
other than 2” will change the C height accordingly.
Dimensions are in inches.

11 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
1.06 POWER AND CONTROL WIRING (ROUGH-IN)
A. Line voltage power supply must be sized to provide adequate power for the
operation of the specic model heat pump and, if chosen, the electric heat option.
Information on line power requirements, line sizing and fuse sizing is shown on data
label on unit. The power leads can enter the heat pump or air conditioner either
through the bottom or rear. The locations of the knockouts for power leads are
shown in Figure 3. Depending on the location of the Scholar III heat pump or air
conditioner relative to the outside wall, the exact rough-in location for power lines in
the school room can be determined. Six feet of power line should be available inside
the cabinet for routing and connecting the power lines, after the Scholar III unit is
installed. If entry is from bottom, the stub-out should be no higher than 1/2” from the
classroom oor to allow the unit to slide into the wall opening.
IMPORTANT
IF “S CIRCUIT” POSITION IS SELECTED ON THE ELECTRIC HEAT CONTROL (SEE
ARTICLE 1.11), LOWER MINIMUM CIRCUIT AMPACITY MAY BE PERMITTED.
B. Low voltage wiring can be roughed in to either the back (outside wall) or bottom
(oor) of the cabinet. Six feet of low voltage wire should be available for routing and
termination within the unit. If the entry is from the bottom, the stub-out should be no
higher than 1/2” from the classroom oor to allow the Scholar III heat pump and air
conditioner to slide into the wall opening. Reference Figure 3 as noted above, for
control wiring entry points into the cabinet.

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 12
Figure 3. Scholar III™ Heat Pump and Air Conditioner Dimensional Data

13 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
1.07 CONDENSATE DRAIN LINE (ROUGH-IN)
A. The condensate drain line can be roughed in to drain the Scholar III™ heat pump or
air conditioner from either the back (outside) or the bottom (oor). The locations for
the condensate stub-outs can be determined from the cabinet knockouts identied in
Figure 3. The factory installed condensate connection within the cabinet is a female
PVC tting designed for a 3/4” slip connection.
CAUTION
INSPECT THE FLEXIBLE CONDENSATE DRAIN LINE INSIDE THE SCHOLAR III™ UNIT
(WHEN INSTALLED) FOR POSSIBLE TUBING COLLAPSE. CORRECT AS APPROPRIATE.
1.08 WET HEAT (ROUGH-IN)
A. Hot water coil connections are made by dropping supply and return lines through
the knockout locations in the top of the plenums, as described in Figure 3 for the heat
pump. Access to the interior cabinet is through these factory-notched locations.
1.09 PREPARATION OF THE SCHOLAR III™ HEAT PUMP AND AIR CONDITIONER
WARNING
TO AVOID PERSONAL INJURY, ADEQUATE PROTECTIVE CLOTHING MUST BE WORN
AND PRECAUTIONS IN HANDLING AND INSTALLING THIS EQUIPMENT MUST BE
PRACTICED AT ALL TIMES.
After the rough-in is complete, the Scholar III™ heat pump or air conditioner and
accessories must be prepared for nal installation prior to start-up. The following
items are to be completed prior to nal installation.
A. Remove the two shipping screws that at the top and bottom of the front door.
B. Open the front door for access to the lag bolts that hold the shipping skids in place.
Unscrew the 4 lag screws. Note: access to the back right lag screw is easier through
the the condensate opening in the back panel beneath the outdoor air box. Remove
the shipping skids.
C. To facilitate moving the Scholar through doors, the out door air box can be removed.
To remove the outdoor air box, remove the 16 screws - 6 on each side and 4 along
the top. Remember to reinstall the outdoor air box before placing the Scholar into its
nal position in the classroom.
D. If the base stand accessory was chosen, install the base stand in accordance with
installation instructions included with the base stand or see Appendix B at end of
manual.
E. Hot Water Plenum. The protective lm on top of the Scholar III™ cabinet and on the
plenum must be removed to install the plenum. Fasten the plenum to the top of the
cabinet in accordance with the instructions included with the plenum or Appendix C at
end of manual.
F. Freeblow Plenum/Ducted Plenum. All Scholar III™ heat pump and air conditioners
use an electronically commutated (EC) blower motor to distribute the conditioned
air throughout the classroom. The EC motor automatically adjusts its speed to
maintain the proper air ow over a wide variety of external static pressures in an air

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 14
distribution system. If only the freeblow plenum is used (no external duct work), the
blower automatically slows down. When duct is used, the EC blower automatically
speeds up to compensate for the additional static pressure. The blower automatically
slows down when in the ventilation mode (compressor off) to deliver the required
cfm of fresh air to the classroom. No eld adjustment of the blower is required. Install
plenum to top of cabinet after shipping plate has been removed from electric heater
(if appropriate). Instructions are included with plenum or see Appendix C at end of
manual.
The air distribution system which is eld supplied and installed downstream of the
specied ducted plenum must be engineered to assure sufcient air ow, even
under adverse conditions, such as dirty lters. The information provided in Figure 1,
Appendix A should be used to design the air distribution system duct size leaving the
Scholar III™ heat pump or air conditioner, keeping the external static pressure to a
minimum.
Applications using duct work should be designed and installed in accordance with the
current edition of the National Fire Protection Association codes and standards 90A
and 90B. The duct system must be engineered to insure sufcient air ow through
the unit to prevent over-heating of the heater element. This includes proper supply
duct sizing, sufcient quantity of supply registers, adequate return and lter area.
Ductwork must be of correct material and must be properly insulated. The duct work
must be constructed of galvanized steel with a minimum thickness of .019. Ductwork
must be rmly attached, secured and sealed to prevent air leakage. Do not use duct
liner on inside of supply duct within four feet of the unit.
Galvanized metal duct extensions should be used to simplify connections to ductwork
and grilles. Use fabric boots to prevent the transmission of vibration through the duct
system. The fabric must be U.L. rated to a minimum of 197°F.
H. Install the outdoor louver/collar assembly to the outdoor side of the wall opening. The
louver/collar assembly may be fastened to the air box (or air box extension) as
described in the instructions for outdoor louvers/collars. The louver must be installed
with the blades pointing downward on the outside and the louver and the collar must
be water sealed to the outside wall surface with the appropriate caulking material.
See the instructions that come with the outdoor louver for installation details or see
Appendix F at the end of this manual.
I. Weather Panels are eld supplied and do not come with the Scholar III™ heat pump
or air conditioner. If a weather panel covers the wall opening described in Figure 2,
remove the weather panel prior to installing the unit into the wall opening.
J. After measuring for correct locations of power/control wiring entry, condensate drain
line, and the appropriate wet heat lines, remove the appropriate knock-out access
ports from the cabinet. Be sure they align with the rough-in points for the noted
pipes and wires. Be sure electrical, condensate and wet heat piping will not cause
interference or be damaged by sliding the Scholar III heat pump or air conditioner into
place.
IMPORTANT
BE SURE TO SEAL THE OPEN AREAS BETWEEN LINES ENTERING THE SCHOLAR
III™ CABINET AND THE KNOCKOUT OPENINGS, TO PREVENT AIR LEAKAGE.

15 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
K. If the heat pump or air conditioner is to t ush against the inside of the exterior
wall, cut to length, strips of open cell polyurethane foam 1” wide by 1/2” thick with
adhesive backing, eld supplied, on one side. This may be applied to the back of the
heat pump and plenum along and ush with the two vertical and top horizontal edges.
These strips will provide a nished appearance to the wall/heat pump interface and
provide a seal between the equipment and wall. If the heat pump or air conditioner is
applied with a side against a wall (in a corner), use the same strip material on the end
panel along the side vertical edge.
L. Prior to sliding the Scholar III™ heat pump or air conditioner into the wall opening,
check to be sure that the oor surface is hard, smooth and level (concrete, wood,
vinyl tile or the equivalent). If the oor is carpeted, cut out an appropriate “footprint”
based on the Figure 3 drawings and the location of the unit relative to the inside
nished wall (ush or offset). Be sure the surface is level or provisions are made to
level the unit upon installation.
M. If the outdoor air box was removed, reinstall it prior before placing the Scholar III™
unit in its nal position. Install the outdoor air box onto the back of the Scholar™
III heat pumps or air conditioners before sliding the unit into position. Apply a
weather-proof sealant; i.e., silicone, onto the back of the Scholar III heat pump or air
conditioner prior to installing the outdoor air box to prevent water leaks.
1.10 INSTALLATION THROUGH THE OUTSIDE WALL.
A. Slide the Scholar III™ heat pump or air conditioner into the wall opening slowly,
being careful to clear the appropriate stubouts. The heat pump or air conditioner,
when installed properly, should have a clearance between the air box outside edge
and the nished outside wall as shown in Figure 4. Proper t up of the louver/collar
assembly to the air box to the outside wall requires the noted recess dimension to be
maintained after installing the unit.
B. To minimize sound in the classroom, insulate all four sides of the outdoor air box that
is internal to the classroom with the following:
Layer 1: 1/2” Rubatex
Layer 2: 1-1/2: Duct Board

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 16
CAUTION
WHEN FASTENING LOUVER/COLLAR ASSEMBLY TO AIR BOX, DO NOT
OVERTIGHTEN LOUVER SCREWS. OVERTIGHTENING SCREWS WILL CAUSE
DAMAGE AND WARP THE LOUVER/COLLAR ASSEMBLY. TO PREVENT WATER FROM
RUNNING DOWN THE INTERIOR OF THE WALL, INSTALL FLASHING UNDER THE
OUTDOOR AIR BOX, OVER THE SILL OF THE WALL.
C. Check (with a spirit level) to see that the heat pump or air conditioner is level and
plumb. If it is not, take the appropriate corrective action to level and plumb the system.
1/8” thick washers with 1/2” pass through holes can be installed appropriately under the
fastener holes in the base of the heat pump or air conditioner to make the system level
and plumb.
D. Secure the heat pump or air conditioner to the oor with appropriate eld supplied
fasteners, through the four 1/2” diameter through holes in the base.
E If the Scholar III™ heat pump or air conditioner is offset from the outside wall, trim
strips should be installed at this time. Check instructions that come with trim strips
for installation or see Appendix D at end of this manual.
F. If appropriate, install wall brackets to the inside surface of the outside wall and to the
cabinet of the Scholar III™ unit, at this time. Check instructions with wall brackets for
installation or see Appendix E at end of this manual.
Figure 4. Dimension Between Scholar III™ Heat Pump or Air Conditioner Air Box and
Finished Outside Wall for Outdoor Louver/Collar Assembly Installatio
FREEBLOW PLENUM
SCHOLAR III™
HEAT PUMP OR
A
IR CONDITIONER
DISTANCE (INCHES) BETWEEN AIR BOX
AND OUTSIDE FINISHED WALL
LOUVER/COLLAR
OUTSIDE WALL
NOTE: TO PREVENT RAIN WATER FROM RUNNING
DOWN THE INTERIOR OF THE WALL, INSTALL FLASHING UNDER
THE OUTDOOR AIR BOX OVER THE SILL OF THE WALL OPENING.

17 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
identication 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 conrm
that the compressor is rotating in the proper direction at the initial eld start-
up of the system. Verication of proper rotation is made by observing that the

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 18
suction pressure drops and the discharge pressure rises when the compressor
is energized. An alternate method of verication for self contained system
with small critical refrigerant charges, where the installation of gauges may be
objectionable, can be made by monitoring the temperature of the refrigerant
lines at the compressor. The temperature should rise on the discharge line
while the suction line temperature decreases. Reverse rotation also results in a
substantially reduced current draw when compared to tabulated values.
There is no negative impact on durability caused by operating three phase
compressors in the reversed direction for a short duration of time, usually
dened as less than one hour. However, after several minutes of operation the
compressor's internal protector will trip. The compressor will then cycle on the
protector until the phasing is corrected. Reverse operation for longer than one
hour may have a negative impact on the bearings.
B. 1. Low voltage wiring must be class 1.
2. For Scholar III™ units with a remote (wall mounted) thermostat, route the low
voltage wiring from the point of entry into the cabinet, upward through the
raceway adjacent to the disconnect shown in Figure 5.
Route wires into the terminal strip compartment through the openings provided.
Connect wiring to the terminal strip as shown in Figure 9 for a remote, wall
mounted thermostat installation.

19 Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8
Figure 5. Electrical Control Box, Access for Ventilation Filters and GreenWheel® ERV
Figure 6. Typical Control Center Layout for Scholar III™
VENTILATION FILTERS
PLC
ELECTRICAL
CONTROL BOX
UNIT
DISCONNECT
Due to the variety of options, the control center in your unit may be different
from the photo. Always refer to the electrical schematic in your unit.

Marvair Scholar III™ VAISA I&S Manual 03/2019 Rev. 8 20
Figure 7. Typical Wiring Schematic for Heat Pump
Single Phase Power