Airxcel Marvair ComPac II AVHDA90 User manual

Chapter 1 Description................................. 5
Chapter 2 Installation............................... 11
Chapter 3 Start-Up ................................... 20
Chapter 4 Troubleshooting ....................... 20
Chapter 5 Maintenance............................. 24
Chapter 6 Warranty .................................. 25
Chapter 7 Start-Up Checklist.................... 26
Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Part #03268
Installation & Operation Manual
10EER 7.5 Ton Vertical Wall Mount
Air Conditioners
Models: ComPac AVHDA90
IMPORTANT
This manual may include information for options and features which may not be
included on the unit being installed. Refer to the unit data label or Model Identication
to determine which features and options this unit is equipped with.
INSTALLER: Afx the instructions on the inside of the building adjacent to the thermostat.
END USER: Retain this manual for future reference.
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.

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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
How To Use This Manual
This manual is intended to be a guide to Marvair's line of vertical air conditioners. It contains installation, troubleshoot-
ing, 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 air conditioner rst read Chapter 1 and scan the entire manual before beginning the installation
as described in Chapter 2. Chapter 1 contains general, descriptive information and provides an overview which can speed
up the installation process and simplify troubleshooting.
If a malfunction occurs, follow this troubleshooting sequence:
1. Make sure you understand how the air conditioner works (Chapters 1 & 3).
2. Identify and correct installation errors (Chapter 2).
3. Refer to the troubleshooting information in Chapter 4.
If you are still unable to correct the problem, contact the Factory at 1-229-273-9558 for additional assistance.
Please read the following “Important Safety Precautions” before beginning any work.
Important Safety Precautions
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 and breakage
or damage to other components.
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 and ordi-
nances.
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 recovering 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.
© 03/2019 Marvair® Div. Airxcel™, Inc.
SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

3Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
WARNING
• 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.
INSTALLER: Afx the instructions on the inside of the building adjacent to the
thermostat.
END USER: Retain these instructions for future reference.
Table of Contents
Chapter 1 Air Conditioner Description & Specications
1.1 General Description .................................................................................................................................5
1.2 Model Identication .................................................................................................................................5
1.3 Serial Number Date Code ........................................................................................................................5
1.4 Capacities, Weights and Filter Sizes ........................................................................................................6
1.5 General Operation ....................................................................................................................................7
1.6 Electronic Control Board Mode of Operation..........................................................................................7
1.7 Optional Controls and Packages ..............................................................................................................9
1.8 Electrical Operation .................................................................................................................................9
Chapter 2 Installation
2.1 Equipment Inspection.............................................................................................................................11
2.2 Installation Requirements.......................................................................................................................11
2.3 Installation Materials .............................................................................................................................12
2.4 Porting and Duct Work ..........................................................................................................................14
2.5 Top Flange Installation ..........................................................................................................................14
2.6 Installing the Lifting Brackets................................................................................................................15
2.7 Mounting the Unit .................................................................................................................................15
2.8 Electrical Connections ...........................................................................................................................16
Chapter 3 Start-Up
3.1 Check-Out of Cooling Cycle .................................................................................................................20
3.2 Check-Out of Heating Cycle..................................................................................................................20
Chapter 4 Troubleshooting
4.1 Overview ................................................................................................................................................20
4.2 Failure Symptoms Guide........................................................................................................................21
4.3 Compressor Troubleshooting .................................................................................................................22
4.4 Control Board Diagnosis........................................................................................................................23

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Table of Contents
Chapter 5 Maintenance
5.1 Scheduled Maintenance .........................................................................................................................24
Chapter 6 Warranty
6.1 Limited Product Warranty......................................................................................................................25
Chapter 7 Start-Up Check List
7.1 Start-Up Check List................................................................................................................................26
Illustrations
Figure 1. Typical Electrical Schematics for Units with Two Compressors ........................................... 10
Figure 2. Top Flange and Lifting Bracket Installation .......................................................................... 15
Figure 3. Wall Mounting Detail............................................................................................................. 16
Figure 4a. Thermostat Connection Diagram ........................................................................................... 19
Figure 4b. CommStat™ 3 Wiring Detail................................................................................................. 19
Tables
Table 1 AVHDA Efciency and Capacity Ratings at ANSI/AHRI Standard 390 .................................6
Table 2 Sensible Capacities - Single Compressor .................................................................................6
Table 3 Sensible Capacities - Dual Compressor....................................................................................6
Table 4 Single Compressor Cooling Performance (BTUH) at Various Outdoor Temperatures ............6
Table 5 Dual Compressor Cooling Performance (BTUH) at Various Outdoor Temperatures...............6
Table 6 Economizer Cooling Performance............................................................................................6
Table 7 Return Air Filter Sizes ..............................................................................................................6
Table 8 Shipping Weights & Dimensions ...................................................................................................... 7
Table 9 Minimum Clearances..............................................................................................................12
Table 10 Voltage Limitations.................................................................................................................12

5Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Chapter 1 Description & Specications
1.1 General Description
The Marvair ComPac is a series of vertical wall-mounted air conditioning systems that provide
heating, cooling, and ventilation for telecommunication shelters, and other applications with high
internal heat gains. The series is available in nominal cooling capacities of 90,000 BTUH. A factory
installed economizer, resistance heating elements and reverse ow congurations are available.
All of Marvair's ComPac models feature an exclusive electronic control board.
The control board consolidates several of the electrical components, improves the air conditioner’s
reliability and has LED’s to indicate operating status and fault conditions to assist the service technician.
A complete description of functions of the control board is in Section 1.6
Other standard components include:
• Hot gas by-pass valve to allow operation in cold temperatures
• Thermal expansion valve to improve both efciency and capacity over a wide range of ambient
temperatures
• Phase monitor to prevent operation if the unit is not properly phased
The ComPac is designed for easy installation and service. Major components are accessible for
service beneath external panels.
All units have internal disconnects. Depending upon state and local code requirements, this feature
may eliminate the need for an external breaker or disconnect.
1.2 Model Identication
The model identication number is found on the data sticker. Rating plate located on side panel.
Cabinet Color
116 = Beige (standard)
216 = Gray
500 = Stainless Steel
(Exterior panels only)
900 = Custom Color
Efficiency Rating
EER 10+
Nominal Cooling
090 =90,000 BTUH
System Type
Air Conditioner
Electric Heat – kW
000 = No Heat
050 = 5 kW
090 = 9 kW
150 = 15 kW
Power Supply
A = 208/230V,1ø,60Hz
C = 208/230V,3ø,60Hz
D = 460V,3ø,60Hz (3 wire)
E = 380V,3ø,50Hz (4 wire)
F = 220V,1ø,50Hz
Z = 575V,3ø,60Hz
Compressor
U = Scroll Compressors
Ventilation
N = Non-Economizer
C = Economizer
Special Option Code
F = Reverse Air Flow2
A5= Built in compliance
with UL 1995,
4th edition
Refrigerant
A = R410A
Dual
Compressors1
VZ = Verizon Specification
AVH D A ••• AC • ••• • • U •• A5 •••
Notes:
1The standard conguration on the AVHDA90 is dual compressors.
2The standard conguration is with the supply (conditioned) air at the top of the unit and the return air below it. In the reverse air ow conguration, the return is at the top and the supply air
below it.
1.3 Serial Number Date Code
A = January E = May J = September D = 2014 H = 2018
B = February F = June K = October E = 2015 I = 2019
C = March G = July L = November F = 2016 J = 2020
D = April H = August M = December G = 2017 K = 2021

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1.4 Capacities, Weights and Filter Sizes
Complete electrical and performance specications and dimensional drawings are in the Product Data
Sheet.
Note: Follow local codes and standards when designing duct runs to deliver the required airow.
Minimize noise and excessive pressure drops caused by duct aspect ratio changes, bends, dampers and
outlet grilles in duct runs.
Basic Model Cooling BTUH1EER2Rated Air Flow (CFM)3
AVHDA90 89,000 10 3,500
1Cooling rated at 95°F (35°C) outdoor and 80°F DB/67° WB (26.5°C DB/19.5°C WB) return air. 2EER=Energy Efciency Ratio
3CFM=Cubic Feet per Minute
Ratings are with no outside air. Performance will be affected by altitude.
Ratings are at 230 volts for 208/230 volt units (“A” & “C” models) and 460 volts for “D” models. Operation of units at a different volt-
age from that of the rating point will affect performance and air ow.
Table 1. AVHDA Efficiency and Capacity Ratings at ANSI/AHRI Standard 390
Return Air
DB/WB Sensible Cooling Capacity Outside Air Temperature ºF (ºC)
75 (24) 80 (27) 85 (30) 90 (32) 95 (35)
79/66
BTUH
40,671 40,148 39,613 39,093 38,561
75/61 42,039 40,581 39,164 37,706 36,248
80/63 43,700 42,201 40,662 39,164 37,665
85/65 48,641 46,940 45,279 43,578 41,918
Table 2. Sensible Capacities - Single Compressor
Return Air
DB/WB Sensible Cooling Capacity Outside Air Temperature ºF (ºC)
75 (24) 80 (27) 85 (30) 90 (32) 95 (35) 100 (38) 105 (41) 110 (43) 115 (46) 120 (49) 125 (52)
79/66*
BTUH
73,746 72,487 71,203 69,958 68,689 67,427 66,204 64,956 64,351 63,780 63,209
75/61 77,983 76,678 75,416 74,126 72,843 71,567 70,298 69,071 68,443 67,817 67,192
80/63 87,060 85,763 84,439 83,158 81,884 79,477 76,184 72,802 71,200 69,598 67,996
85/65 98,806 97,367 95,972 94,552 93,174 91,805 90,411 89,060 88,371 87,782 87,194
Table 3. Sensible Capacities - Dual Compressor
Basic Model Outdoor Temperature
75ºF / 24ºC 80ºF / 26.5ºC 85ºF / 29ºC 90ºF / 32ºC 95ºF / 35ºC
AVHDA90AC 46,980 45,360 43,740 42,120 40,500
Based upon ANSI/AHRI std. 390 return air conditions of 80°F DB/67° WB (26.5°C DB/19.5°C WB) at various outdoor temperatures.
Table 4. Single Compressor Cooling Performance (BTUH) at Various Outdoor Temperatures
Basic Model Outdoor Temperature
75ºF / 24ºC 80ºF / 26.5ºC 85ºF / 29ºC 90ºF / 32ºC 95ºF / 35ºC
AVHDA90AC 103,240 99,680 96,120 92,560 89,000
Based upon ANSI/AHRI std. 390 return air conditions of 80°F DB/67° WB (26.5°C DB/19.5°C WB) at various outdoor temperatures.
Table 5. Dual Compressor Cooling Performance (BTUH) at Various Outdoor Temperatures
Basic Model Fan Watts Fan CFM EER @ 55 F OAT Outside Air Temperature ºF (ºC)
50 (10) 55 (13) 60 (16) 65 (18) 70 (21)
AVHDA90AC 730 3500 125 110,128 91,140 72,153 53,165 34,178
Based upon indoor setpoint temperature of 79 (26).
Table 6. Economizer Cooling Performance
MODEL Description INCHES MILLIMETERS PART NO. FILTERS PER UNIT MERV RATING
AVHDA90 Exterior Access Return Air Filter 25" x 16" x 2" 635 x 406 x 51 80137 3 8
Interior Access Return Air Filter 15" x 20" x 2" 381 x 508 x 51 92365 3 8
Table 7. Return Air Filter Sizes

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MODEL Unit Weight Shipping Weight Shipping Dimensions Height Width Depth
LBS KG LBS KG Inches MM Inches MM Inches MM
AVHDA90 1,160 527.3 1,285 584.1 98 2,489 56 1,422 48 1,219
Table 8. Shipping Weights & Dimensions
1.5 General Operation
Hot Gas By-Pass
Normally used in specialty applications (i.e Magnetic Resonance Imaging (MRI) buildings) to prevent
magnetic voltage disturbance caused by cycling. This technology is applied in this product to extend
the operation envelope for the compressor to 20º F (-6.6ºC). Combined with a condenser low ambient
Fan Cycle feature, compressor operation can be extended to 0º F (-17.8ºC). During Hot Gas operation
mode, system performance will be reduced. If product operation is in mild outdoor ambient conditions,
the installed shut-off ball valve may be closed, thus disabling the Hot Gas By-Pass feature.
Refrigerant Cycle (Cooling Mode)
The air conditioners use R-410A refrigerant in a conventional vapor-compression refrigeration cycle to
transfer heat from air in an enclosed space to the outside. A motorized impeller assembly blows indoor
air across the evaporator. Cold liquid refrigerant passing through the evaporator is boiled into gas by
heat removed from the air. The warmed refrigerant gas enters the compressor where its temperature
and pressure are increased. The hot refrigerant gas condenses to liquid as heat is transferred to outdoor
air drawn across the condenser by the condenser fan. Liquid refrigerant is metered with a thermal
expansion valve (TXV) into the evaporator to repeat the cycle.
AVHDA (Dual Compressor) Units: The AVHDA is factory wired for maximum cooling utilizing both
compressors. If 2 stage compressor operation is desired, the factory installed jumper between terminals
1 and 2 of the low voltage terminal strip must be removed. The 1st stage cooling input is terminal 1 of
the low voltage terminal strip and the 2nd stage cooling input is terminal 2 of the low voltage terminal
strip. The thermostat must be programmed for 2 stage cooling operation when 2 stage compressor
operation is desired.
Heating Mode
A wall-mounted thermostat controls the heating cycle of models which incorporate resistance heating
elements. On a call for heat, the thermostat closes the heat relay to energize the indoor fan and the
resistance elements.
1.6 Electronic Control Board Mode of Operation
Normal
24 VAC power must be continuously applied to “R” and “C”. Upon a call for cooling “Y” and with the
high pressure switch (HPS) closed, the compressor will be energized. (Note: See the delay on make
feature.) The compressor will remain energized during the 3 minute timed low pressure by-pass cycle. If
the low pressure switch (LPS) is open after the 3 minute by-pass cycle, the compressor will de-energize.
Lock-out
If either of the fault conditions (LPS or HPS) occurs twice during the same call for cooling, the control
board will enter into and indicate the lockout mode. In the lockout mode, the compressor is turned off.
If there is a call for indoor air ow “G”, the blower remains energized, the alarm output is energized and
the status LED will blink to indicate which fault has occurred. When the lockout condition is cleared, the
unit will reset if the demand for the thermostat is removed or when the power is reset. With the control
board, the user can now have either normally closed or normally open remote alarm dry contacts. The
air conditioners are factory wired to be normally open.

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Delay on Break
If the compressor is de-energized due to a loss of a cooling “Y” call or the rst fault, the unit re-start will
be delayed 3 minutes from the time the contactor is de-energized. (Note: There is no delay on break if
the lockout condition is reset.)
Delay on Make
On initial power up only, the unit will wait 0.03 to 10 minutes from the cooling “Y” call before allowing
the contactor to energize. The delay can be adjusted by the DOM wheel on the board. Factory recom-
mended wait is 3 minutes.
Low Pressure By-Pass Time
When starting, the low pressure switch (LPS) fault condition will be by-passed for 3 minutes before the
contactor is de-energized.
Post Purge
Upon a call for indoor airow “G” the blower will energize immediately. When in the cooling mode, the
blower will remain energized for 10 to 90 seconds (adjustable) after the compressor has been de-energized.
The time period can be changed by fan purge wheel on the board. Factory setting is 90 seconds.
LEDs Post Purge Wheel Delay on Make
(Compressor Time Delay)
Wheel
LED Indicator Lights
COLOR TYPE STATUS DESCRIPTION
Green Power Contstant On 24 VAC power has been applied
Red Status Contstant On Normal operation
Red Status 1 Blink High pressure switch has opened twice
Red Status 2 Blinks Low pressure switch has opened twice
High Pressure Switch
The high pressure switch is mounted on the liquid line. It is electrically connected to a lockout circuit
on the board which shuts down the system if the refrigerant pressure rises to 650 PSIG. This protects the
unit if airow through the condenser is blocked or if the outdoor fan motor fails.
Although the contacts of the high pressure switch close when the refrigerant pressure falls to approximately
450 PSIG, the system must be manually reset once the lockout circuit is activated. A manual reset is
necessary to prevent harmful short-cycling. To reset switch, turn primary power off, then back on or turn
thermostat system switch off, then back on.
Low Pressure Switch
The low pressure switch is mounted on the compressor suction line. It is designed to open if the refrigerant
pressure drops to 40 PSIG; it resets when the pressure rises to 60 PSIG. The switch protects the unit if
airow through the indoor blower is impeded, if the blower motor fails, or if there is a loss of refrigerant.

9Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
1.7Optional Controls & Packages
Protective Coating Packages
Two corrosion protection packages are offered- one for the condenser section (the Coastal Environmental
package) and the other for the entire unit (the Coat-All Package).
The condenser protection package includes:
• Corrosion resistant fasteners
• Sealed or partially sealed condenser fan motor
• Two layer epoxy/urethane applied to all exposed internal copper and metal in the condenser section
• A protective coating on the condenser coil
The Coat-all package includes all of the above but also includes a protective coating on the evaporator
coil and the two layer epoxy/urethane on all exterior and interior components and sheet metal. (Note:
the internal sheet metal which is insulated and the internal control box are not coated).
Dirty Filter Indicator
A diaphragm type of indicator measures the air pressure on either side of the lter and when the pressure
drops below the set point, a red LED is illuminated. The set point is adjustable.
Protective Coil Coatings
Either the condenser or evaporator coil can be coated. For harsh conditions, e.g., power plants, paper
mills or sites were the unit will be exposed to salt water, the condenser coil should be coated. Note:
Cooling capacity may be reduced by up to 5% on units with coated coils.
Cabinet Color and Material
The air conditioners are available in two standard cabinet colors -the standard grey with beige as an
option. The standard cabinet’s sides, top and front panels are constructed of 16 gauge painted steel.
Contact your Marvair representative for color chips, custom colors and 316 stainless steel cabinets.
Dual Compressors With Lead/Lag Operation
Freeze Sensor On Indoor Coil
Prevents frost on the indoor coil caused by a loss of air ow or restrictive duct work.
Filter Access From Return Air Grille
Factory or eld installed lter bracket allows changing and access to the lters from the return air grille.
See model ID, special option code “I”.
Reverse Air Flow Conguration
Location of Supply and Return Air Openings are reversed.
1.8Electrical Operation
The compressor and condenser fan are energized with a contactor controlled by a 24 VAC pilot signal.
Some compressors incorporate an internal PTC crankcase heater that functions as long as primary power
is available. The heater drives liquid refrigerant from the crankcase and prevents loss of lubrication
caused by oil dilution. Power must be applied to the unit for 24 hours before starting the compressor.
The condenser (outside fan) motor is energized by the same contactor.
The indoor evaporator fan motor is controlled by the fan purge on the electronic control board.

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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Figure 1. Typical Electrical Schematic for Units with Two Compressors

11 Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Chapter 2 Installation
WARNING
Failure to observe and follow Warnings and Cautions and these Instructions could result
in death, bodily injury or property damage. Read this manual and follow its instructions
and adhere to all Cautions and Warnings in the manual and on the unit.
2.1 Equipment Inspection
Concealed Damage
Inspect all cartons and packages upon receipt for damage in transit Remove cartons and check for
concealed damage. Important: keep the unit upright at all times. Remove access panels and examine
component parts. Inspect refrigerant circuit for fractures or breaks. The presence of refrigerant oil usually
indicates a rupture. If damage is apparent, immediately le a claim with the freight carrier.
Units that have been turned on their sides or tops may have concealed damage to compressor motor
mounts or to the oil system. If the unit is not upright, immediately le a claim for concealed damages
and follow these steps:
1. Set unit upright and allow to stand for 24 hours with primary power turned on.
2. Attempt to start the compressor after 24 hours.
3. If the compressor will not start, makes excessive noise, or will not pump, return the unit to the
freight carrier.
2.2 Installation Requirements
General
1. Inspect unit for completeness. Check for missing parts (e.g. hardware). Refer to the installation kit
information in section 2.3.
2. Remove access panels and check for loose wires. Tighten screw connections.
3. Complete and mail the warranty registration card.
You must consider all of the following when choosing the installation site:
1. Noise. Install the unit so that the least amount of noise will be transmitted to inhabited spaces.
2. Condensate Drainage. Condensate produced during operation must be discharged to a suitable
drain.
3. Placement.
A) Place the unit in a shaded area, if possible.
B) Install it above ground for protection against ooding.
C) The unit exhausts air. Be sure that the airow is not impeded by shrubbery or other obstructions.
D) When installing multiple units, please note the recommended clearances noted in Table 4.
4. Airow Requirements:
Maximum Static Pressures AVHDA90
IWG 1.8
Pa 450
Keep duct lengths as short as possible. Do not obstruct airow through the unit.
Duct work should be designed and installed in accordance with all applicable safety codes and

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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
standards. Marvair strongly recommends referring to the current edition of the National Fire Pro-
tection Association Standards 90A and 90B before designing and installing duct work. 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,
and adequate return and lter areas. Duct work must be of correct material and must be properly
insulated. Duct work must be constructed of galvanized steel with a minimum thickness of .019
inches. Duct work must be rmly attached, secured, and sealed to prevent air leakage. See section
2.4 for additional duct work requirements.
5. Clearances:
Note the minimum clearances required for proper operation and service.
MODEL
MIN. CLEARANCE
AROUND SIDES
(SINGLE UNIT)
MIN. CLEARANCE BETWEEN
UNITS (TWO UNITS)
MIN. SPACE
ABOVE UNIT
MIN. SPACE
BEHIND UNIT
AVHDA90 24 inches (61 cm) 24 inches (61 cm) 24 inches (61 cm) 120 inches (305 cm)
Table 9. Minimum Clearances
6. Codes:
Make sure your installation conforms to all applicable electrical, plumbing, building, and municipal
codes. Some codes may limit installation to single story structures.
7. Electrical Supply:
The power supply must have the appropriate voltage, phase, and ampacity for the model selected.
Voltage must be maintained above minimum specied values listed below. Refer to the data sticker
on the unit for ampacity requirements.
Electrical Rating Designations* A D Z
Nominal Voltage 208/230 460 575
Phase 1 3 3
Minimum Voltage 197 414 518
Maximum Voltage 253 506 632
* Letters refer to model number code designations. Refer to page 5.
Table 10. Voltage Limitations
2.3 Installation Materials
The AVHDA90 is shipped with a top bracket and lifting brackets. The top bracket provides a method of
sealing the top of the unit from water intrusion. The bracket is shipped attached to the top of the unit.
Before installing the unit, remove the bracket and reattach as described in Section 2.5
The Lifting brackets are shipped attached to the back panel of the unit. These brackets provide a method
for lifting it. The installation of the brackets is described in Section 2.6.

13 Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Kit Components:
Accessories:
The package may include other factory-supplied items (optional):
P/N Description
K/10439 CommStat Touch Controller, Solid State Lead/Lag Controller w/Touch Screen
S/07846 CommStat 4 Controllers, Solid State Lead/Lag Controller
50123 Digital thermostat. 1 stage heat, 1 stage cool. 7 day programmable. Fan switch: Auto &
On. Auto-change over. Keypad lockout. Non-volatile program memory.
93189 Double Deection Aluminum Supply grille for the AVHDA90.
42½ x 151/4 (1,080 x 387)
93188 Aluminum Return air grille for the AVHDA90.
42½ x 21½ (1,080 x 546)
Additional Items Needed:
Additional hardware and miscellaneous supplies (not furnished by Marvair®) are needed for installation.
The list below has the items typically needed for mounting a unit on a wood frame wall structure.
Concrete or berglass structures have different requirements. Marvair cannot recommend a specic
method of attaching the air conditioner to the building due to the wide variety of building types, code
requirements, wall construction and specic installation conditions. The installation of the air conditioner
to the building must take in to account all of these factors and follow best industry practices to provide
a safe and secure attachment to the building.
• Mounting bolts for unit mounting anges. The length needed is typically the wall thickness plus
one inch (25 mm).
• Washers
• Hex nuts
• Silicone Sealer to seal around cracks and openings
• Minimum 5 conductor low voltage multicolored wire cable (i.e. thermostat wire)
• Appropriate electrical supplies such as conduit, electrical boxes, ttings, wire connectors, etc.
• High voltage wire, sized to handle the MCA (minimum circuit ampacity) listed on the data plate.
• Over-Current Protection Device sized in accordance with the MFS (maximum fuse size) listed on
the unit data plate.
WARNING FIRE HAZARD
Improper adjustment, alteration, service, maintenance or installation could cause serious injury,
death and/or property damage.
Installation or repairs made by unqualied persons could result in hazards to you and others.
Installation MUST conform with local codes or, in the absence of local codes, with codes of all
governmental authorities have jurisdiction.
The information contained in this manual is intended for use by a qualied service agency that is
experienced in such work, is familiar with all precautions and safety procedures required in such
work, and is equipped with the proper tools and test instruments.

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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
2.4 Porting and Duct Work
General Information
Note: The following instructions are for general guidance only. Due to the wide variety of installation
possibilities, specic instructions will not be given. When in doubt, follow standard and accepted
installation practices, or contact Marvair®for additional assistance.
Wall Openings
Measure the dimensions of the supply and return ports on the unit.
Cut the openings in the exterior wall for the supply and return. IMPORTANT: All units with electric
heat must have 1" (25.4mm) clearance on all four sides of the supply outlet duct ange on the
unit. The 1" (25.4mm) clearance must extend on all sides of the supply duct for the rst 3 feet (1
meter) from the unit.
IMPORTANT: Marvair requires a minimum of 1" (25.4mm) from the surface of any supply ducts
to combustible material for the rst 3 feet (1 meter) of the duct.
Ducting
Extensions should be cut ush with the inside wall for applications without duct work.
Applications using duct work should be designed and installed in accordance with all applicable safety
codes and standards. Marvair strongly recommends referring to the current edition of the National Fire
Protection Association Standards 90A and 90B before designing and installing duct work. 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. Duct work
must be constructed of galvanized steel with a minimum thickness of .019 inches for the rst 3 feet (1
meter). Ductwork must be rmly attached, secured and sealed to prevent air leakage. Do not use duct
liner on inside of supply duct within 4 feet (122cm) of the unit.
Galvanized metal duct extensions should be used to simplify connections to duct work 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 (92°C).
Minimum Airow Requirements
The duct system must be engineered to assure sufcient air ow through the unit even under adverse
conditions such as dirty lters, etc.
2.5 Top Flange Installation (See Figure 2)
1. All models have built-in side mounting anges.
2. Attach the top ange to the top of the air conditioner. The holes in the top of the air condtioner have
been predrilled. Remove the 4 screws in these holes and use these screws to attach the top ange
to the air conditioner.
3. Apply a bead of silicone sealer on the wall side of the bottom support brackets on the unit. Circle
the mounting holes with the silicone bead.

15 Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Figure 2. Top Flange and Lifting Bracket Installation (Typical)
2.6 Installing the Lifting Brackets
The units have lifting brackets that can be installed on the top of the side panels. These brackets allow
the unit to be picked up thru lifting eyes in the brackets. The lifting brackets are shipped attached to
the back panel of the AVHDA unit. Attach the brackets to the left and right side panels as shown in
Figure 2. The 4 screws for attaching the brackets are shipped in the holes at the top of the side panels.
When attaching the brackets, make sure the top of the bracket is angled towards the center of the unit.
2.7 Mounting The Unit
1. For wiring into the back of unit, locate the lower of the two knockouts on the wall side of the unit.
Drill a one inch hole in the shelter wall to match this opening. Allow sufcient clearance to run
3/4" conduit through the hole and to the unit.
2. Lift the unit into position using an appropriate and safe lifting device.
3. Make sure that the duct anges are properly aligned with the wall opening. Adjust as necessary.
4. Note the holes in each side ange. Using the holes for guides, drill holes through the wall with a
drill bit. Insert the bolts through the anges. Install nuts and washers on the inside of the shelter.
Tighten the bolts to secure the unit.
5. Apply a bead of silicone where the side and top anges contact the exterior wall.
6. On the inside of the shelter, install the wall sleeves in the supply and return air openings. The sleeves
may be trimmed to t ush with the inside wall.
7. Check the t of each sleeve to its mating ange for possible air leaks. Apply silicone sealer to close
any gaps. Install the air return and supply grilles.

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For units with electric heat, a one inch clearance is required around the duct extensions. The duct extensions must be constructed of
galvanized steel with a minimum thickness of .019” as per the NFPA standards 90A & 90B.
Figure 3. Air Conditioner Wall Mount Detail
2.8 Electrical Connections
WARNING ELECTRICAL SHOCK HAZARD
Failure to follow safety warnings exactly could result in serious injury, death, and/or
property damage.
Turn off electrical power at fuse box or service panel BEFORE making any electrical
connections and ensure a proper ground connection is made before connecting line
voltage.
Important
All electrical work must meet the requirements of local codes and ordinances. Work should be
done only by qualied persons.
The units may incorporate an internal crankcase heater for compressor protection. The crankcase
heater must be energized for at least 24 hours prior to starting the compressor.
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 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

17 Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
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.
To change the rotation, turn off power to the unit and reverse L1 & L2 at the disconnect in the air
conditioner.
The middle front panel provides access to the electrical/control box and to the lters. This panel has hinges
on the left and right hand side. This panel should ONLY be opened by using the two hinges on the left
side OR the two hinges on the right side. NEVER OPENALLFOUR HINGES SIMULTANEOUSLY.
If all four hinges are opened simultaneously, the front panel will drop and may cause serious injury
and damage the panel.
DANGER
NEVER open all four hinges simultaneously. The panel should ONLY be opened by using
the two hinges on the left side OR the two hinges on the right side.
High Voltage Wiring
The power supply should have the proper voltage, phase, and ampacity for the selected model.
1. Refer to the electrical data on the data sticker on the unit for eld wiring requirements of the unit.
Size the incoming power supply lines and the fuse(s) or HACR breaker(s) according to requirements
described in the National Electric Code. Run the power conductors through the knockouts on the
side or back of the unit. Use appropriate conduit and strain reliefs.
CAUTION
Note: Power supply service must be within allowable range (+10% - 5%) of rated voltage
stamped on the unit rating plate. To operate nominal 230/208V unit at 208V, change the
transformer line tap from 240V to 208V following the instruction on wiring label in unit.
2. Connect the wires to the input side of the internal breaker or terminal block L1, L2, & L3 for three-
phase models.
3. Install the ground wire on the ground lug.
4. For units designed for operation on 208/230V, 60Hz power supply, the transformer is factory wired
for a 230V power supply. For a 208V power supply, remove the orange lead from the transformer
and connect the red lead. Insulate the orange lead.
CAUTION
The external breaker(s) that provide power to the air conditioner must be sized per the
maximum Fuse Size (MFS) shown on the Unit's data label.
Dual Unit Phasing
For applications where one controller operates two units, e.g., the CommStat 4.
1. Wire each unit as described in steps 1 through 4 above.

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2. Test for proper phasing as follows:
A. Power up the units.
B. Using an AC volt meter set to the 300 volt scale, measure voltage between terminal L1 on
the compressor contactor of unit #1 and terminal L1 on the compressor contactor of unit #2 If
voltage is present, units are wired out of phase and must be rewired.
C. If units are not in phase, turn off power and reverse the eld power leads connected to the
internal circuit breaker on one of the units only.
D. Restore power and retest the phase (step B). When the voltage reads "0", the units are in phase.
E. Turn off power and proceed.
Low Voltage Wiring
IMPORTANT. The following instructions are generic wiring instructions and may not be applicable
for air conditioners with various options. Always refer to the wiring diagram in the air conditioner for
the proper method to wire your unit.
1. On single units, pull the low voltage wiring (e.g., 18 gauge 4-conductor Class 2 thermostat wire)
from the air conditioners into the thermostat / subbase assembly. See Figure 4a for connections to
various thermostats.
2. Mount the thermostat on the wall of the shelter. The thermostat should be located so that the supply
air from the unit does NOT blow directly on to the thermostat. Connect the thermostat to the terminal
block in the air conditioner as shown in Figure 6a.
3. On dual units, refer to either the CommStat Touch or CommStat 4 Controller Specication sheet.
Wire the two air conditioners to the Lead/Lag Controller, according to the wiring diagram on the
specication sheet.
Remote Signalling: Terminals 5 & 7(N.O.) and 6 & 7 (N.C.) on the air conditioners terminal board are dry
contacts which can be used for remote signalling in the event of a/c cutoff on low or high pressure limit.
Continuous fan operation: For continuous indoor fan operation on single units, install a jumper between
terminals 8 and 3.
CommStat Touch and CommStat 4 Lead /Lag Controller
Please refer to the Product Data sheet for the CommStat Touch or CommStat 4 controller for complete
instructions on installing and programming this controller.

19 Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Figure 4a. Thermostat Connection Diagram
Figure 4b. CommStat 3 Wiring Diagram

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Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
Chapter 3 Start-Up
3.1 Check-Out of Cooling Cycle
Important: Be sure that the crankcase heater (if used) has been energized for at least 24 hours
before starting the unit(s). Double-check all electrical connections before applying power. All air
conditioners with scroll compressors running on 3Ø power must be checked for proper rotation
during the initial start-up. Please refer to Section 2.8 for determining if the 3Ø compressors are
rotating correctly. Incorrect rotation can damage the compressor and is not covered by the warranty
Procedure:
1. Set the cooling set point temperature on the wall thermostat to a point higher than the ambient
temperature. Set the heating set point temperature to a temperature that is lower than the ambient.
2. Set the thermostat system switch in the AUTO position. Nothing should operate at this time.
3. Set the time delay in the control box to three minutes. See Section 1.6.
4. Slowly lower the thermostat's cooling set point temperature until the switch closes. The indoor fan
should operate.
Once the indoor fan turns on, allow approximately three minutes for the compressor to start.
5. To stop cooling, slowly raise the thermostat cooling set point to a temperature higher than the
ambient.
If the unit fails to operate, refer to the troubleshooting information in Chapter 4.
Follow the same procedure for additional units.
NOTE: The fan purge allows the indoor fan to run for approximately 90 seconds after the compressor
is off. This operation provides a small improvement in system rated efciency.
3.2 Check-Out of Heating Cycle
Procedure: (Applies only to units with resistance elements)
1. Raise the heating set point temperature to a setting which is higher than the ambient temperature.
The fan and electric heat should immediately cycle on.
2. Move the system switch to the "OFF" position. All functions should stop.
Chapter 4 Troubleshooting
4.1 Overview
The middle front panel provides access to the electrical/control box and to the lters. This panel has hinges
on the left and right hand side. This panel should ONLY be opened by using the two hinges on the left
side OR the two hinges on the right side. NEVER OPENALLFOUR HINGES SIMULTANEOUSLY.
If all four hinges are opened simultaneously, the front panel will drop and may cause serious injury
and damage the panel.
DANGER
NEVER open all four hinges simultaneously. The panel should ONLY be opened by using
the two hinges on the left side OR the two hinges on the right side.