Work Boat Air Conditioners
Models MVS & MVW
Air Source Models MVS60-90-120-144 Water Source models MVW60-90-120-144
Installation and Operation Manual
MVx90
MVx60/120/144
Chapter 1
Introduction & Safety Information..................................................................... 2
Chapter 2
General Description.......................................................................................... 3
Chapter 3
Installation Preparation..................................................................................... 4
Chapter 4
Installation....................................................................................................... 8
Chapter 5
Electronic Control Board.................................................................................. 14
Chapter 6
Initial Start-Up & Shut Down........................................................................... 15
Chapter 7
Maintenance.................................................................................................. 17
Chapter 8 Troubleshooting.............................................................................................. 18
Chapter 9
Warranty........................................................................................................ 19
Appendix A Dimensional Drawings................................................................................... A-1
Appendix B Wiring Schematics.........................................................................................B-1
Appendix C Start-Up Check List........................................................................................C-1
Marvair® Division of AIRXCEL™, Inc
PO Box 400 • Cordele, GA 31010
156 Seedling Dr. • Cordele, GA 31015
(229) 273-3636 • Fax (229) 273-5154
Email: [email protected]
www.marvair.com/marine
Marvair® Marine UK
Unit 6 Benridge Park • Holyrood Close
Poole, Dorset BH17 7BD.
+44 (0)1202 650700
www.marvair.co.uk
MVS/MVW Installation & Operation Manual
September 2011 NEW
P/N 01850
Work Boat Air Conditioner
Introduction & Safety Information
Chapter 1
This manual is intended to be a guide to Marvair Marine’s line of vertical air and water source
air conditioners. 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 MVS or MVW air conditioners, first read Chapter 1 & 2 and scan the
entire manual before beginning the installation as described in Chapter 4. Chapter 2 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 conditioners works (Chapters 2 & 5).
2. Identify and correct installation errors (Chapter 4).
3. Refer to the troubleshooting information in Chapter 8.
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.
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 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 recovering or adding refrigerant
6. Use COMMON SENSE – BE SAFETY-CONSCIOUS
This is the safety alert symbol
. When you see this symbol on the 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.
Failure to comply will result in death or severe personal injury and/or property
DANGER damage.
Failure to comply could result in death or severe personal injury and/or property
WARNING damage.
CAUTION Failure to comply could result in minor personal injury and/or property damage.
IMPORTANT is used to point out helpful suggestions that will result in improved installation,
reliability or operation.
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Work Boat Air Conditioner
2.1 General Description
Chapter 2
The Marvair Marine self-contained water and air cooled air conditioners are designed for indoor
use in marine applications for both new installations and for replacement of older, less efficient
units. The air conditioners are available in cooling capacities of 5, 7½, 10 and 12 tons (60,000,
90,000, 120,000 & 144,000 BTUH’s) and are controlled by a conventional 24 VDC wall mounted,
HVAC type thermostat. The vertical configuration minimizes floor space and blends into a variety
of working environments. The cool, dry air can be discharged directly into the room or ducted
into adjacent rooms. To ensure years of dependable performance, all components are housed in a
superior corrosion resistant steel cabinet.
Air Cooled Units The MVS air cooled units have an indoor air mover, coil, compressor and
controls. A remote condenser (not provided by Marvair) connects to the MVS unit with field
installed refrigerant lines. The units are shipped with a dry nitrogen charge and may be used with
either R-22 or R-407c refrigerant.
Water Cooled Units The MVW water cooled air conditioners are packaged units shipped from
the factory with R-407c refrigerant and an internal condenser and ready to run. The coaxial
tube-in-tube condenser is constructed of corrosion resistant cupronickel water tubing and copper
refrigerant tubing for use in either fresh or sea water.
The 10 and 12 ton air conditioners have two compressors, allowing for staged operation. The dual
compressors can be programmed to start sequentially, minimizing start-up amps. In addition to
better humidity control and comfort, the dual compressors provide back-up protection, increased
operating efficiencies and energy savings.
The units are pre-piped and wired, minimizing installation time. The readily accessible control
center contains all the control components. On the MVS (air cooled) units, a 24 VAC relay is
included to cycle the condenser fans ON & OFF with the compressors.
Each condensate pan has two drains to prevent condensate from standing in the base pan.
The drain lines are internally tied together and trapped. The condensate drain line opening is
conveniently located on the right side of the air conditioner to facilitate connection of the external
condensate line.
High and low pressure switches with a lock out relay protect the compressors under abnormal
operating conditions. A three minute delay on make safeguards the compressors from destructive
short cycling. The evaporator coils have a baked polyester coating rated to 1,000 hours salt spray
test. The return air filters are located behind the return air grille and are accessible from the front
of the unit.
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2.2 Model Identification
•
•••
Refrigerant
N = Nitrogen charge
C = R-407c
MVS = Marine Vertical Split (air source)
MVW = Marine Vertical Water (water source)
AC
•••
Nominal Cooling
Capacity (BTUH)
60= 60,000
90= 90,000
120=120,000
144=144,000
Air Conditioner
•
Power Supply
C = 208-230V, 3ø, 60Hz
D = 460V, 3ø, 60Hz
•••
Cabinet Color
216 = Gray Cabinet (standard)
116 = Beige Cabinet (optional)
2.3 Serial Number Date Code
A =
B =
C =
D =
E =
F =
Month
Year
January G = July A = 2011
February H = August B = 2012
March J = September C = 2013 April K = October D = 2014
May L = November June M = December
IMPORTANT
WHEN THE AIR CONDITIONER IS INSTALLED, MODEL NUMBER AND SERIAL
NUMBERS ARE TO BE RECORDED AND MAINTAINED IN A LOCATION FOR IMMEDIATE
ACCESS WHEN REQUESTING FURTHER INFORMATION CONCERNING THIS UNIT.
3.1 Installation Preparation
Chapter 3
Inspect the air conditioner
The air conditioners are shipped on 4” x 4” wood base frames and wrapped in shrink wrap.
Remove the shrink wrap and verify the model number of the unit against the shipping order.
Make sure power supply at site matches the power supply of the air conditioner. Check the
air conditioner for any damage that may have occurred during shipping, especially concealed
damage. If the air conditioner is damaged or the shipment is not complete, immediately (within 14
days) file a claim with the freight company.
The units should be stored inside and not exposed to weather.
Installation requirements
The MVS and MVW air conditioners must be installed on a hard, level, smooth surface. Do not
install the air conditioner on a carpeted floor.
Condensate
The locations of the condensate openings are shown on the dimensional drawings in Appendix A.
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The factory installed condensate connection on the cabinet is a female, PVC fitting designed for a
¾” slip connection.
Access for the condensate tubing is on the right side or the unit.
CAUTION
INSPECT THE FLEXIBLE CONDENSATE DRAIN LINE INSIDE THE AIR CONDITIONER
FOR KINKS OR OBSTRUCTIONS IN THE LINE. CORRECT AS REQUIRED.
Power and control (thermostat) wiring
Line voltage power supply must be sized to provide adequate power for the operation of the
specific model air conditioner. Information on line power requirements, line sizing and fuse sizing
is shown on data label on unit. The line power conductors and control (thermostat) conductors
enter the air conditioner through knockouts on the right side of the cabinet. The location of the
knockouts are shown on the dimensional drawings in Appendix A.
Depending on the location of the air conditioner, the exact rough-in location for power lines and
low voltage conductors in the room can be determined. Allow sufficient length for both the high
and low voltage conductors (approximately 6 feet) from the outside of the cabinet to the low
voltage terminal board and the internal disconnect.
Location and Clearances
All MVS and MVW air conditioners have hinged doors on the front to facilitate access to the
primary components. The doors can be removed from the cabinet by removing the pins in each
door.
Thirty-six inches must be allowed in front of the units to permit the doors to swing open. For
units with right side electrical, condensate, refrigerant and water connections, allow sufficient
space between the air conditioner and an obstruction, e.g. a wall, to connect the lines.
Minimum clearance in the rear is zero inches. Clearance above the unit side depends on the space
required for the plenum and ductwork.
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Clearance for connections:
20" (508mm)
Clearance for door opening:
36" (914mm)
Figure 1. Clearances
3.2 Water connections on MVW water cooled air conditioners
The water in and water out connections on the air conditioners are on the right side of the
unit. Since the MVW120 & 144 have two compressors and each compressor can operate
independently, two sets of water pipes are required.
3.3 Remote air cooled condenser for MVS units
On MVS units with a remote condenser(s), locate the condenser(s) so that air flow is unrestricted
on all sides and above the condenser. Place the remote condensing unit(s) according to the
condensing unit’s installation instructions. Select a location that will minimize the length and
complexity of the piping runs. See Table 1 for size of piping. The refrigerant connections for
the units are on the right side of the unit. Since the MVS120 & 144 have two compressors and
each compressor can operate independently, two sets of refrigerant lines and two independent
condensers or a condenser with two independent circuits are required. An appropriately sized
condenser must be selected based upon the cooling capacity of the compressor.
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Model
Circuit
Unit
Connect
Size
Length of Run (feet)
0-25
26-50
51-75
76-100
101-125
126-150
HG
LIQ
HG
LIQ
HG
LIQ
HG
LIQ
HG
LIQ
HG
LIQ
HG
LIQ
MVS60
1
½
½
5/8
½
7/8
½
7/8
½
7/8
½
7/8
½
7/8
5/8
MVS90
1
½
½
7/8
½
7/8
½
7/8
½
1-1/8
5/8
1-1/8
5/8
1-1/8
5/8
1
½
½
5/8
½
7/8
½
7/8
½
7/8
½
7/8
½
7/8
5/8
2
½
½
5/8
½
7/8
½
7/8
½
7/8
½
7/8
½
7/8
5/8
1
½
½
7/8
½
7/8
½
7/8
½
1-1/8
5/8
1-1/8
5/8
1-1/8
5/8
2
½
½
7/8
½
7/8
½
7/8
½
1-1/8
5/8
1-1/8
5/8
1-1/8
5/8
MVS120
MVS144
Table 1. Recommended Refrigerant Line Sizes
Duct
The evaporator blowers in the MVS and MVW units were selected to be used with duct. Refer to
Table 2 for air flow at various static pressures.
Model
Number
Indoor Motor / Blower
Air Flow (CFM) at External Static Pressure (in. wg)
HP
Qty
0.2
0.4
0.6
0.8
1.0
MVx60
3/4
MVx120
MVx120
Speed
One
1,850
1,750
1,650
1,510
1,400
1
High
One
2,505
2,295
2,100
1,885
1,665
1
Medium
One
2,230
2,050
1,875
1,685
1,465
1
Low
One
1,925
1,800
1,680
1,455
1,325
1
High
Two
5,010
4,590
4,200
3,770
3,330
1
Medium
Two
4,460
4,100
3,750
3,370
2,930
1
Low
Two
3,850
3,600
3,360
2,910
2,650
Air flows were measured with a wet indoor coil.
Table 2. CFM at Various Static Pressures
CAUTION
THE DUCT SYSTEM MUST BE ENGINEERED TO PROVIDE SUFFICIENT AIR FLOW
THROUGH THE AIR CONDITIONER, EVEN UNDER ADVERSE CONDITIONS SUCH
AS A DIRTY FILTER. PROPER DESIGN OF THE DUCT SYSTEM IS CRITICAL TO
MAXIMUM PERFORMANCE AND QUIET OPERATION.
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Chapter 4
4.1 Installation
Rig and place the air conditioner
WARNING: UNITS ARE HEAVY
THE MVS AND MVW AIR CONDITIONERS WEIGH 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 AIR CONDITIONER, IT MAY BE NECESSARY TO LAY THE
UNIT ON ITS SIDE ON DOLLIES. IF THIS IS REQUIRED, USE MULTIPLE DOLLIES
AND PLACE THE UNIT ON ITS LEFT SIDE. THE UNIT SHOULD NOT REMAIN ON ITS
SIDE ANY LONGER THAN REQUIRED FOR THE ACTUAL MOVING PROCESS. IF THE
AIR CONDITIONER HAS BEEN ON ITS SIDE, DO NOT ATTEMPT TO START THE UNIT
UNTIL IT HAS BEEN VERTICAL FOR AT LEAST 24 HOURS.
To lift the air conditioners, use slings with a spacer under the base skid to prevent damage to the
cabinet when using a hoist. The air conditioners are designed to minimize noise and vibration. If
additional dampening is desired, place a rubber mat or other material designed for this purpose
and of sufficient quality to support the weight of the air conditioner. Unit must be level; not to
exceed 1/8” per linear foot in any direction.
Figure 2. Rigging Details
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MVS refrigerant line connections and charging
Install the remote air cooled condenser in accordance with the installation instructions provided
with the condenser. Locations for the connection of the refrigerant lines are shown on the
dimensional drawings in Appendix A. Recommended line sizes are shown in Table 1.
Trap Must Be Above Condenser Coil
Remote
Condensing
Unit
Line Slopes Toward Condenser
MVS Unit
Hot Gas Line
Liquid Line
Hot Gas Line
MVS Unit
Liquid Line
Line Slopes Toward Condenser
Remote
Condensing
Unit
Figure 3a. Condenser above evaporator
Figure 3b. Evaporator above condenser
The MVS air conditioners are shipped with a holding charge of nitrogen. After refrigerant
connections are made, release the nitrogen, evacuate, leak test and charge the system as described
below.
Charging MVS units
A. When outdoor condenser is not precharged with refrigerant.
1. Open hot gas and liquid line service valves.
2. Purge the nitrogen holding charge evacuate and leak test the system.
3. Using standard refrigeration charging techniques and charging charts, add refrigerant as required to maintain proper operating conditions. Additional charge is required for piping runs over 25 feet (760 cm). Add charge at the rate of 0.38 oz. per foot for piping runs over 25 feet (760 cm).
B. When outdoor condenser is precharged with refrigerant.
1. Connect line sets to the indoor unit and outdoor condensing unit.
2. Purge the nitrogen from the indoor unit, evacuate and leak test the unit.
3. Open the service valves and add refrigerant to maintain proper operating conditions. Additional charge is required for piping runs over 25 feet (760 cm). Add charge at the rate of 0.38 oz. per foot for piping runs over 25 feet (760 cm).
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IMPORTANT
CHARGE THE COMPRESSOR ON BOTH THE HIGH AND LOW SIDES SIMULTANEOUSLY TO PREVENT AXIAL LOADING OF THE SCROLL, WHICH MAY CAUSE A
TEMPORARY NO START CONDITION FOR THE COMPRESSOR. IF THIS OCCURS,
LEAVE THE COMPRESSOR OFF FOR 30 MINUTES BEFORE RESTARTING, ALLOWING
THE INTERNAL PRESSURES TO EQUALIZE. IF REMOVING THE COMPRESSOR,
EVACUATE BOTH THE HIGH AND LOW SIDE SIMULTANEOUSLY.
Use charging chart supplied with the condenser, if available. If not available, block off enough of
the condenser coil to maintain 220 psig discharge pressure and charge to 15°F to 20°F subcooling
according to Table 3, Required Liquid Line Temperature (°F) at Service Valve.
Required
Liquid Pressure (PSIG) at Service Valve
Subcooling
134 141 148 156 163 171 179 187 196 205 214 220 223 233 243 253 264 274 285 297 309 321 331 346 359
(°F)
0
76 79 82 85 88 91 94 97 100 103 106 108 109 112 115 118 121 124 127 130 133 136 139 142 145
5
71 74 77 80 83 86 89 92 95 98 101 103 104 107 110 113 116 119 122 125 128 131 134 137 140
10
66 69 72 75 78 81 84 87 90 93 96 98 99 102 105 108 111 117 120 123 126 129 129 132 135
15
61 64 67 70 73 76 79 82 85 88 91 93 94 97 100 103 106 109 112 115 118 121 124 127 130
20
56 59 62 65 68 71 74 77 80 83 86 88 89 92 95 98 101 104 107 110 113 116 119 122 125
25
51 54 57 60 63 66 69 72 75 78 81 83 84 87 90 93 96 99 102 105 108 111 114 117 120
Table 3. Required Liquid Line Temperature (°F) at Service Valve R-22
MVW water line connections
The MVW air conditioners have an internal condenser. The location of the water in and water
out connections are shown on the dimensional drawings in Appendix A. Size the water lines to
provide the minimum water flow rates shown in Table 4.
When connecting the water lines, hold the condenser inlet and outlet stubs firmly with a wrench
to prevent twisting. Observe all applicable codes.
Minimum Seawater Flow Rates
Model
Gal/Hr
Liters/Min
MVW60
1,250
79
MVW90
1,800
114
MVW120
2,400
151
MVW144
2,800
182
Table 4. Minimum Seawater flow rates by Model
Proper water flow is absolutely critical to the operation of the air conditioner. If the pipe is too
small, back pressure is created causing a drop in water flow, even if the pump is correctly sized. If
the piping is too large, the slow velocity of the water may cause silt build-up and barnacle growth
inside the piping, eventually restricting water flow.
The best material for sea water piping and fittings is cupronickel. Suitable materials for piping
are hi-grade bronze cupronickel and schedule 80 PVC pipe. Materials to avoid are yellow
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Work Boat Air Conditioner
brass, copper, poor grades of aluminum, stainless steel or steel pipe. Use Teflon® tape or other
appropriate sealant on all threaded fittings to prevent leaks.
Duct
Connect the duct or plenum to the flange on top to the units.
The duct system must be engineered to insure sufficient air flow. This includes proper duct
sizing and a sufficient number of supply registers. Duct must be firmly attached, secured and
sealed to prevent air leakage. When using insulated flexible duct, make sure that the inner duct
is secured and sealed to an adapter before pulling the insulation over the connection. Install the
supply grilles (if used) high on the cabin wall to create good air circulation. Insulate all transitions
and plenums. Stretch the duct tight in straight runs. Make bends and turns as large as possible.
Galvanized metal duct extensions may be used to simplify connections to duct work and grilles.
Use fabric boots to prevent transmission of vibration through the duct system. If the duct is in
storage or other high traffic areas, protect it from being crushed with a shield or box.
To prevent short cycling of the air conditioner, take care not to direct the conditioned air directly
onto the thermostat.
DANGER CARBON MONOXIDE POISONING
IF THE DUCT MUST BE RUN THROUGH AREAS CONTAINING ENGINES OR FOSSIL
FUEL DEVICES, IT IS ABSOLUTELY MANDATORY THAT THE DUCT SYSTEM BE
AIR TIGHT TO PREVENT CARBON MONOXIDE AND ANY OTHER HAZARDOUS
GASES OR VAPORS FROM BEING INTRODUCED INTO THE CONDITIONED AIR
SYSTEM. SEE ABYC STANDARD “A-6 REFRIGERATION AND AIR CONDITIONING
EQUIPMENT” FOR MORE INFORMATION ON INSTALLING DUCT THROUGH THESE
AREAS.
Condensate connection and disposal
The air conditioners will produce significant quantities of condensate in most marine applications
that may cause significant damage to the vessel if not disposed of properly. The condensate
openings on the units are from the right side. Refer to the drawings in Appendix A for the exact
location of the condensate openings.
DANGER CARBON MONOXIDE POISONING
IF THE CONDENSATE LINE MUST BE RUN THROUGH AREAS CONTAINING
ENGINES OR FOSSIL FUEL DEVICES, IT IS ABSOLUTELY MANDATORY THAT
THE LINE BE AIR TIGHT TO PREVENT CARBON MONOXIDE AND ANY OTHER
HAZARDOUS GASES OR VAPORS FROM BEING INTRODUCED INTO THE
CONDITIONED AIR SYSTEM. SEE ABYC STANDARD “A-6 REFRIGERATION AND
AIR CONDITIONING EQUIPMENT” FOR MORE INFORMATION ON INSTALLING A
CONDENSATE LINE THROUGH THESE AREAS.
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4.2 Electrical Connection
WARNING ELECTRIC SHOCK HAZARD
FAILURE TO FOLLOW SAFETY WARNINGS EXACTLY COULD RESULT IN SERIOUS
INJURY, DEATH AND OR PROPERTY DAMAGE. TURN OFF ELECTRICAL POWER AT
SERVICE PANEL BEFORE MAKING ANY ELECTRICAL CONNECTIONS AND ENSURE
A PROPER GROUND CONNECTION IS MADE BEFORE CONNECTING LINE VOLTAGE.
All electrical work must meet the requirements of all applicable codes and ordinances. Work
should only be done by qualified persons.
If the wiring diagram that is on or was shipped with the unit is different from the one in this
manual, refer to and use the wiring diagram that is on or was shipped with the unit.
High Voltage Wiring
The MVS and MVW air conditioners are available for operation on a 208/230v. 3ø, 60 Hz.
or a 460v, 3ø, 60 Hz. Power supply. Refer to the data label on the air conditioner for field
requirements. The electrical data list fuse/HACR breaker and wiring size amps.
a) The power supply must have the proper voltage, phase and ampacity for the selected
model.
b) Refer to the data label on the unit for field wiring requirements. The electrical data lists
fuse and wire sizes for the unit.
c) Each unit has a Minimum Circuit Ampacity (MCA). Field wiring must be used that is
of sufficient size to carry that amount of current. Use copper conductors only. Refer to
the National Electrical Code for complete current carrying capacity data on the various
insulation grades of wiring materials.
d) Power supply must be within allowable range of ±10% of rated voltage.
e) The unit must be properly grounded to reduce the risk of shock or electrocution.
f) A properly sized circuit breaker must be used. Information required to size the breaker is on
the data sticker on the unit.
g) The breakers must be motor rated type B or, preferably type C.
h) Connections between the ship’s alternating current grounding conductor and the ship’s
negative or bonding system must be made as part of the ship’s wiring as per ABYC
standard E-11 or equivalent.
i) When servicing or replacing existing equipment that contains a chassis mounted ground
lug, the service person or installer must verify the ship’s wiring for the connection required
in item e & h. above.
j) All electrical connections must be made within the electrical junction boxes supplied
with the unit. A terminal strip and/or electrical connectors are provided for component
installation.
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IMPORTANT
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 suction pressure drops and the
discharge pressure rises when the compressor is energized. An alternate method of verification
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 defined 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.
1. Size the incoming power supply lines according to Code requirements. Run the power
conductors through the knockouts on the right side of the unit. Use appropriate conduit and
strain reliefs.
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.
5. 460V units have a step down transformer for 230V motors.
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Low Voltage (Control) Wiring
IMPORTANT
The following instructions are generic wiring instructions and may not be applicable for all
thermostats. Always refer to the wiring diagram in the air conditioner for the proper method to
wire your unit. The air conditioner uses an electronic thermostat mounted in the conditioned
space. The MVx60 and MVx90 have one compressor. A single stage cooling thermostat may be
used with these units. The MVx120 and MVx144 air conditioners have two compressors. For
optimal temperature control, a 2-stage cooling thermostat should be used with these units.
1. Pull the low voltage wiring (e.g., 18 gauge 4-conductor Class 2 thermostat wire) from the
air conditioner into the thermostat / sub base assembly. See Figure ? in Appendix B for
connections to various thermostats.
2. Mount the thermostat on the wall of the cabin. 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 conditioner as shown in Figures ? in Appendix B.
Electronic Control Board
Chapter 5
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 flow “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 contacts by moving a wire on the control board. The air conditioners are factory
wired to be normally open.
Delay on Break
If the compressor is de-energized due to a loss of a cooling “Y” call or the first 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.)
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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 recommended 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 airflow “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.
LED Indicator Lights
COLOR
TYPE
STATUS
DESCRIPTION
Green Power
Constant On
24 VAC power has been applied
Red
Status
Constant 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 compressor discharge line. It is electrically connected
to a lockout relay which shuts down the system if the refrigerant pressure rises to 450 PSIG. This
protects the unit if airflow 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 300 PSIG, the system must be manually reset once the lockout relay 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 35 PSIG; it resets when the pressure rises to 60 PSIG. The switch
protects the unit if airflow through the indoor blower is impeded, if the blower motor fails, or if
there is a loss of refrigerant.
Chapter 6
Initial Start-Up & Shut Down
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.
MVS & MVW air conditioners with scroll compressors running on 3Ø power must be checked
for proper rotation during the initial start-up. Please refer to Chapter 4 for determining if the
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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 cabin
temperature.
2. Set the thermostat system switch in the AUTO or COOL position. Nothing should operate at
this time.
3. Set the time delay on the control board in the control box to three minutes.
4. On MVW units (water source) turn on the condenser water supply. On MVS units, open the
refrigerant lines. Refer to 4.1 for recommended installation procedures.
5. 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. On MVS units, verify operation of the condenser fans. The fans should be
running during compressor operation.
6. While the compressor is operating, check for proper phasing as described in Chapter 4.
7. 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 7.
8. Set thermostat for comfort as desired.
NOTE: The fan purge allows the indoor fan to run for approximately 90 seconds after the
compressor is off.
Air Conditioner Shut Down
Turn thermostat’s selector switch to the OFF position. Do not shut off main power to the unit
except to service the air conditioner.
Winter Shut Down (MVW water cooled units only)
1. If the air conditioner may be exposed to freezing temperatures, drain the water from the
condenser and all water piping.
2. Pump a non-corrosive, potable anti-freeze solution throughout the system’s water supply and
discharge lines. Be sure to follow all state, local and federal ordinances if discharging the antifreeze solution overboard.
3. Run the air conditioner until a steady stream of anti-freeze solution is being discharged.
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Chapter 7
Maintenance
Scheduled Maintenance
Marvair® strongly recommends that the air conditioner be serviced a minimum of twice a year. At
this time the filters, evaporator coil, condenser coil(s), the cabinet, and condensate drain should be
serviced as described below.
In addition to this seasonal check-out, the air conditioner should be maintained as follows:
Air Filter
Replace the air filters whenever it is visibly dirty. Never operate the air conditioner without
the return air filters in place. If washable filters are used, flush with hot water or steam or soak
in a mild water solution with soap or detergent. Refer to filter manufacturer’s instructions as
necessary.
Evaporator
If the evaporator becomes clogged or dirty, it may be cleaned by careful vacuuming or with a
commercial evaporator cleaning spray. DO NOT use a solvent containing bleach, acetone, or
flammable substances. Turn off power before cleaning. Be careful not to wet any of the electrical
components. Be sure the unit has dried before restarting.
Use a fin comb of the correct tooth spacing to straighten mashed or bent fins.
Condenser
MVS units (air cooled). TURN OFF POWER BEFORE CLEANING! Be sure that all electrical
components are thoroughly dry before restoring power.
Periodically inspect the outdoor condenser for dirt or obstructions. Remove foreign objects such
as leaves, paper, etc. If the condenser coil is dirty, it may be washed off with a commercial solvent
intended for this purpose.
MVW units (water cooled). Verify that the unit has proper water flow. If insufficient water flow,
check any strainers and pumps for debris. If water flow still insufficient, descaling of the water
lines may be required.
Cabinet
The cabinet may be cleaned with a sponge and warm, soapy water or a mild detergent. Do not
use bleach, abrasive chemicals or harmful solvents.
Drains
Regularly check the condensate drain. An obstruction will force water to dump into the middle of
the unit and drain out the sides of the air conditioner, causing water on the floor.
Lubrication
Oiling of the the evaporator blower motor is not required as the motor is sealed and does not need
oiling
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Chapter 8
Troubleshooting
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Chapter 9
Warranty
Marvair® Marine Warranty for Models MVS & MVW air conditioners
Parts
If any part of your Marvair unit fails because of a manufacturing defect within fifteen months
from the date of original shipment by Marvair of the air conditioner or within twelve months
from the date of start-up of the air conditioner, whichever is the earlier date, Marvair will furnish
without charge, EXW Cordele, Georgia, the required replacement part.
The responsibility of the Owner of the Equipment includes the following:
1. To operate the equipment according to the manufacturer's instructions.
2. To provide easy accessibility for service.
3. To check and reset circuit breaker(s) and disconnect before calling for service. (Circuit
breaker(s) may be in the main service panel.)
4. To keep the unit clean and free of dirt.
5. To clean and/or replace the filters as required.
6. To keep the evaporator coil clean and on MVW units to keep the condenser coil free of
sediment or scale. On MVS units, to keep the both the evaporator and condenser coils
clean.
7. To pay the charges incurred when any of the above have not been done.
8. To pay for repair or replacement of any material or part other than those within the Marvair
unit or thermostat itself.
9. To check any fuses on the circuit board and replace as required.
The owner of the product may ship the allegedly defective or malfunctioning product or part
to Marvair, at such owner’s expense, and Marvair will diagnose the defect and, if the defect is
covered under this warranty, Marvair will honor its warranty and furnish the required replacement
part. All costs for shipment and risk of loss during shipment of the product or part to Marvair
and back to the owner shall be the responsibility and liability of the owner. Upon request by
an owner, Marvair may arrange for remote diagnosis and repair of the allegedly defective or
malfunctioning product or part.
An owner requesting performance under this Warranty shall provide reasonable access to the
allegedly defective or malfunctioning product to Marvair and its authorized agents and employees.
This warranty does not cover damage caused by improper installation including any refrigerant
leaks in the tubing and fittings between the evaporator and condenser sections on split systems;
misuse of equipment; negligent servicing; damage due to use of the product for purposes other
than those for which it was designed; damage caused by natural disasters, power surges, lightning
and submersion; damage caused by unauthorized modifications; and damage caused by improper
wiring or power supply to the air conditioner including operating the unit with an undersized
generator or condenser.
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THIS WARRANTY AND SERVICE POLICY CONSTITUTE THE EXCLUSIVE REMEDY
OF ANY PURCHASER OF A MARVAIR AIR CONDITIONER AND IS IN LIEU OF
ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT
LIMITATION, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS
FOR USE, TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT SHALL
ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR USE
EXCEED THE TERMS OF THE APPLICABLE WARRANTY STATED ABOVE AND
MARVAIR SHALL HAVE NO OTHER OBLIGATION OR LIABILITY. IN NO EVENT
SHALL MARVAIR BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES
OR MONETARY DAMAGES.
THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO
HAVE OTHER RIGHTS WHICH VARY FROM STATE-TO-STATE. Some states do not allow
limitations or exclusions, so the above limitations and exclusions may not apply to you.
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Appendix A - Dimensional Drawings
Dimensional Drawings - MVx60
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Dimensional Drawings - MVx90
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Dimensional Drawings - MVx120/144
REFRIGERANT OR WATER
LINE CONNECTION
REFRIGERANT OR WATER
LINE CONNECTION
UNIT
MVS/MVW120
MVS/MVW144
“X”
56 3/8”
63 1/2”
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REFRIGERANT OR WATER
LINE CONNECTION
REFRIGERANT OR WATER
LINE CONNECTION
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Appendix B - Electrical Schematics
Electrical Schematics - MVS60 for 460v., 3ø, 60 Hz. Power Supply
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Electrical Schematics - MVS120 for 460v., 3ø, 60 Hz. Power Supply
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Electrical Schematics - MVW120 for 460v., 3ø, 60 Hz. Power Supply
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Appendix C - Start-Up Check List
A. Equipment Information
Marvair Air conditioner Compressor:
Compressor:
Condenser:
Model No.________________
Model No.________________
Model No.________________
Model No.________________
Serial No.________________
Serial No.________________
Serial No.________________
Serial No.________________
B. Pre-Start Up
Indoor Unit
Is there any shipping damage? (Y/N)_________
If so, where?_____________________________________________________________
________________________________________________________________________
Will this damage prevent starting the unit? (Y/N)_________
Check Power Supply, does it agree with data sticker on air conditioner? (Y/N)_________
Has the ground wire been connected? (Y/N)_________
Has the circuit protection been sized and installed properly? (Y/N)_________
Controls
MVS air cooled units only.
a) Has fan control for the remote condenser(s) been installed? (Y/N)_________
b) Do outdoor condenser fans operate when required? (Y/N)_________
Are thermostat and indoor blower control wiring connections made and checked?
(Y/N)_________
Are all wiring terminals (including main power supply) tight? (Y/N)_________
Has crankcase heater been energized for 24 hours? (Y/N)_________
Is control transformer wired for correct voltage? (Y/N)_________
Evaporator Section
Has water been placed in drain pan to confirm proper drainage? (Y/N)_________
Has trap been properly installed? (Y/N)_________
Are correct filters in place? (Y/N)_________
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Water Piping (MVW water cooled units only)
Have water connections been checked? (Y/N)_________
Is water circulating pump operating properly? (Y/N)_________
Refrigerant Piping (MVS units only)
Have leak checks been made at the valves and all refrigerant connections, including,
solenoid valves, filter driers with a leak detector? (Y/N)_________
If leaks are found, repair and report any leaks. __________________________________
C. Check Voltage Imbalance
Line to Line Volts
AB_______V
AC________V
BC______V
(AB + AC + BC)/3 = Avg. Voltage = _______________
Max. deviation from avg. voltage = ______________volts
Voltage imbalance = (100 x Max. Deviation)/avg. Voltage = ___________%
If the voltage imbalance is greater than 2%, do not attempt to start the air conditioner!
Correct imbalance before starting the unit.
D. Check & Record Refrigerant Pressures
After 10 minutes of compressor operation, record the following:
Suction Pressure
Circuit 1
________
Circuit 2
_________
Suction Line Temperature
________
_________
Discharge Pressure
________
_________
Discharge Line Temperature
________
_________
Entering Condenser Air or Water Temp
________
_________
Leaving Condenser Air or Water Temp
________
_________
Evap. Entering Air DB Temp
________
_________
Evap. Entering Air WB Temp
________
_________
Evap. Leaving Air DB Temp
________
_________
Evap. Leaving Air WB Temp
________
_________
Compressor Amps (L1)
________
_________
Compressor Amps (L2)
________
_________
Compressor Amps (L3)
________
_________
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Notes:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
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