Dometic DX Remote & Self-Contained A/C Installation And Operation Manual

DX Remote & Self-Contained A/C v

INSTALLATION • OPERATION

Direct Expansion Systems
Revised: 20170710

L-2086

v

English

v

English

L-2086

Table of Contents

DX Remote & Self-Contained A/C Systems

• Introduction

Drawings and Diagrams ..................................................................4

Air Conditioning Basics ....................................................................4

The Effect of Seawater Temperature ...............................................4

Types of DX Systems .......................................................................4

Subsystems ....................................................................................5

System Controls ..............................................................................5

Condensate Drain ............................................................................5

DX Remote & Self-Contained A/C Systems

• Installation

Installation Procedures ...................................................................6

Electrical System .............................................................................6

Installing The Self-Contained A/C Unit 6

Selecting the Site .............................................................................6

Site Location Checklist ....................................................................7

Mounting the Self-Contained Unit ....................................................7

Installing The Condensing Unit 7

Selecting the Site ............................................................................7

Site Location Checklist ....................................................................7

Mounting the Remote Condensing Unit ...........................................7

Installing The Cooling/Heating Unit 8

Selecting the Site ............................................................................8

Site Location Checklist ....................................................................8

Mounting the Cooling/Heating Unit ..................................................8

Installing the Refrigerant Tubing ......................................................8

Installing the Seawater Cooling System 9

Importance of a Self-Draining System .............................................9

Through-Hull Inlet Fitting .................................................................9

Seacock ...........................................................................................9

Strainer ............................................................................................9

Seawater Pump ...............................................................................9

Manifolds .......................................................................................10

Overboard Discharge .....................................................................10

Seawater Piping ............................................................................10

Bonding ......................................................................................... 10

Installing The Air Distribution System 10

Return Air Grill (RA Grills) .............................................................10

Ducts .............................................................................................10

Discharge Air Grill .......................................................................... 11

Installing the Control Unit 11

The SMX Control ......................................................................... 11

The Rotary Knob Switch Assembly ................................................ 11

Installing the Pump Relay 11

Location ......................................................................................... 11

Voltage and Triggers ......................................................................12

Electrical Connections 12

Three Phase Power ....................................................................... 12

Final Inspection 13

Inspecting the Seawater Cooling System ......................................13

Inspecting the Self Contained Unit ................................................13

Inspecting the Condensing Unit

(Remote Condensing Unit Systems Only) ..................................13

Inspecting the Cooling/Heating Unit

(Remote Condensing Unit Systems Only) ..................................13

Inspecting the Refrigerant Connections

(Remote Condensing Unit Systems Only) ..................................13

Inspecting the Air Distribution System ...........................................13

Inspecting the Control/Switch Assembly and Electrical Wiring ...... 13

Charging the System with Refrigerant 14

Charging a New System ................................................................ 14

Field Charging the System.............................................................14

Removing Refrigerant from the System .........................................15

Initial Start Up 15

DX Remote & Self-Contained A/C Systems

• Operation

Operating Instructions - Rotary Controls 16

SA & SSA Models ..........................................................................16

Operation Instructions - SMX Controls 16

SMX II/SMX Net Operation ............................................................16

Power On .......................................................................................16

System Off ..................................................................................... 16

Selecting Setpoint..........................................................................16

Displaying Temperature ................................................................. 16

Cool Mode ..................................................................................... 17

Heat Mode ..................................................................................... 17

Automatic Changeover ................................................................ 17

Manual Fan Speed Control ............................................................ 17

Automatic Fan Speed Control .......................................................17

Adjusting Brightness ...................................................................... 17

Using The Humidity Control Routine ........................................... 17

Anti-Ice Routine ............................................................................. 17

Owner Maintenance - Routine 18

Condensate Drains ........................................................................18

Air Filters ........................................................................................18

Seawater Connections ...................................................................18

Seawater Pump .............................................................................18

Seawater Strainer ..........................................................................18

Refrigerant Gas ............................................................................. 18

Winterizing the System .................................................................. 18

Trouble Shooting Limited

Descriptions of Figures

18

19

Copyright 2004 Dometic Corporation, All Rights Reserved - Every precaution has been taken in the preparation of this manual to insure its accuracy. However, Dometic Corporation assumes no

responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of this product and information contained herein.

3

v

English

L-2086 Introduction

DX Remote & Self-Contained A/C Systems • Introduction

Warning

This manual contains essential information concerning
the safe and proper installation and operation of your
Cruisair air conditioning system. If there are any state­ments or procedures in this manual that you do not un­derstand, contact the Dometic Corporation Applications
Department for assistance. Phone
804-746-1313 (8 am - 5 pm US Eastern Time),
Fax [phone], or email [e-mail].

Notice

US federal law prohibits the intentional release of refrig­erant gases into the environment, including the R -22 re­frigerant used in most Cruisair air conditioning systems.
Special care must be taken when installing, charging,
and servicing Cruisair equipment to prevent any loss of
equipment. Only EPA certied technicians with the prop­er equipment should perform service on the refrigerant
circuit of the system.

Drawings and Diagrams

The gures that are referenced throughout this manual can be
found immediately after the warranty section of the manual. In
addition, some Cruisair equipment will be shipped with specic
installation sheets or wiring diagrams that may supercede the
information located in this manual.

Air Conditioning Basics

The basic principle of an air conditioner is the movement of
heat. In a direct expansion (DX) water-cooled air conditioner,
heat is transferred from the cabin air to the refrigerant gas,
which then releases the heat into the seawater. In reverse cycle
heating (heat pump), the refrigerant ow is reversed and heat
is extracted from the seawater and then discharged into the
cabin.

The heat exchange process relies on the movement of both
cabin air and seawater to effectively work. If air ow or seawa
ter ow is compromised, the efficiency of the system will drop,
and the unit could eventually be damaged, or at least shut
down on one of its safety protection devices.

Part of the cooling process, in addition to lowering the air tem
perature, is the removal of moisture from the air. This lowers
the humidit
helps keep the boat dry, reducing mold growth and other mois
ture related problems.

y, which makes the area feel more comfortable and

-

-

-

best when the seawater temperature is below 90°F (32°C). At
higher water temperatures the unit will operate, but at reduced
capacity. As the water temperature rises, so does the refriger
ant gas pressure. A high-pressure safety switch will shut the

wn if the water temperature gets too hot, or there is a

unit do
loss of cooling water ow.

In heat mode, the opposite is true. As the seawater tem
perature gets colder, there is less heat available and heating
perf

ormance drops. Full heating capacity is available in water
temperatures as low as 55°F (13°C), but drops to about 50%
capacity in 40°F (4.4°C) water. Below this, the refrigerant pres
sure can be so low that the unit will not produce heat, (or may
shut do

wn on low-pressure fault, if this option is installed).

-

-

-

Types of DX Systems

Self-contained units have all major mechanical compo­nents of an air conditioning system mounted on one chassis,
including the compr
blower, electrical box and related parts.

The self-contained unit is normally mounted low in the living
area - under a settee or berth, or in a closet or locker. Cabin
air is pulled into the unit, where it is cooled or heated, then dis
charged through ducting to a grill usually located on a bulkhead
high in the compartment.

The refrigerant circuit in a self-contained unit is pre-charged
and sealed at the factory, and no additional charging is needed
at installation. A typical self-contained unit is shown in Figure 1.

Remote systems, also called split-gas, have the air condition
ing components mounted on two separate chassis that are
installed in different locations and are connected by copper
refrigerant tubing.

The condensing unit consists of the compressor, seawater
condenser, and electrical components, and is mounted in the
engine room or other mechanical space.

The cooling/heating unit includes the evaporator coil and a
fan or blower mounted on a drip pan. It is installed in the living
area in a similar manner to a self-contained unit. Two or three
cooling/heating units can be connected to one condensing unit
so that multiple or large cabins can be cooled.

A remote system must be charged with refrigerant after instal
lation by a certied technician. A typical condensing unit is
shown in Figure 2, and Figure 3 is a typical draw-through type
cooling/heating unit.

essor, seawater condenser, evaporator coil,

-

-

-

The Effect of Seawater Temperature

The efficiency of the system is dependent on both the seawater
and cabin temperatures. In cooling, the air conditioner works

4

v

English

L-2086 Introduction

Subsystems

Both self-contained units and remote condensing systems
require subsystems that are purchased separately because of
the many variations and options available. These include the
seawater, air distribution, and control subsystems.

Seawater System

The seawater cooling system consists of an inlet through-hull
tting, seacock (water shut-off valve), strainer, pump, and
overboard discharge tting all connected by hose or piping. If
multiple air conditioning units are served by a single seawater
pump, then a pump relay and water manifold are required.

Air Distribution System

Cabin air is drawn into the self-contained unit or cooling/heat­ing unit through a return air grill. It is then cooled or warmed
and b

lown back into the cabin through a ducting system. The
air should be discharged high in the cabin and away from the
return air grill to ensure good circulation. An air lter is locat
ed on the cooling unit or on the return air grill and must be
cleaned r

egularly.

-

System Controls

Two different types of controls are available, either an electro­mechanical rotary knob switch assembly or one of the Cruisair
SMX ser

The electromechanical switch assemblies are typically 3-knob
switches that control mode (OFF, FAN, RUN), thermostat
(temperature setting), and fan speed. Other versions include 1
and 2 knob switches for control of “slave” cooling units, and a
4-knob switch for use on systems with auxiliary electric heat.

ies of microprocessor controls.

grammable functions allow the user to customize the system to
suit the specic needs of their boat and boating en

The two SMX control systems available are SMX II and the
SMX Net. Each system consists of:

• Power/Logic (P/L) board - Monitors and controls all func
tions of the air conditioning unit. SMX II and SMX Net hav
different P/L boards and are not interchangeable.

• Keypad/Display - The SMXir is a 10-button user interface
with a digital readout and LED indicators. It is used with
SMX II or SMX Net systems.

• Temperature-Sensing Element - Air temperature is moni
tored by a temperature-sensing element (TSEP) that plugs
into the power/logic board.

• Connecting Cable - The keypad/display connects to the
P/L board with a CX or CXP connecting cable.

SMX Net systems may also have additional network cables
and an outside temperature sensor that plug into the P/L board.

vironment.

-

Condensate Drain

When the air conditioner is running in the cooling mode, mois­ture is removed from the air by the evaporator coil. This con­densation is then caught in a drain pan and must be drained
of

f to a sump or overboard. In humid climates the system can
produce a large amount of condensate water that could cause
signicant damage to your boat if the drain system doesn’t
work properly.

e

-

Cruisair SMX controls are advanced microprocessor systems
that provide a more comfortable environment and better system
protection than mechanical controls. In addition, over 20 pro

-

5

v

English

L-2086 Installation

DX Remote & Self-Contained A/C Systems • Installation

Installation Procedures

This rst section covers installation procedures for Cruisair
direct expansion (DX) air conditioning systems, both self-con­tained units and remote systems. Please read and understand
the man

ual before attempting to install any equipment.

SMX Installation

For installation instructions for your SMX Control, refer to
SMXII Control Systems (L-2066) or the SMX Net Control Sys­tems (L-2067) manuals.

Electrical System

Cruisair air conditioning systems are available for use with
common power supplies throughout the world. In the United
States and most of North and South America, the systems are
115V or 230V, 60Hz, single phase AC (alternating current). In
Europe and most of Asia, power systems are typically 230V
50Hz single phase.

Compressors larger than 20,000 Btu/hr are only available in
230V single phase, 230V or 380/460V 3 phase. On 380/460V
3-phase units there is often a separate, lower voltage circuit for
the controls and blower, either 115V or 230V. On some power
systems this can be supplied by using one input line and the
neutral. If not, a separate control power feed or a transformer
will be required.

Running and starting loads of an air conditioning system are of
ten the largest electrical loads on a boat. It is important that the
po

wer supply system is large enough to handle these loads,
and is installed properly. Contact an electrician if you are not
sure about the proper wiring procedures. Always follow local
codes or ABYC codes for proper wiring guidelines.

Voltage and Frequency

The voltage rating of a unit is a nominal rating. The actual
voltage in a given location may be higher or lower by as much
as 10% and the system will still operate ne. For example, at
60 Hz, you will sometimes see 110VAC to 120VAC, or 208VAC
to 240VAC, or 440VAC to 480VAC. In a 50Hz environment,
common voltages range from 220V to 240V, or 380V to 415V.

When choosing a system, the voltage and frequency must be
known. While standard 60Hz equipment can often be run at
50Hz, it will experience a 17% drop in performance, however,
50Hz equipment can not be run at 60Hz because the 50Hz
motor will run too fast and cause damage. Seawater pumps
will lose even more performance at 50 Hz due to the nature of
centrifugal pumps.

at 50Hz. If a boat is traveling in 50Hz and 60Hz environments,
then 60Hz equipment should be installed, with special attention
to sizing (especially the pumps) so that the system performs up
to expectations. When running 60Hz equipment at 50Hz, the
voltage should be reduced 17% to prevent overheating a motor.

Installing The Self-Contained
A/C Unit

Safety Warning

A Cruisair self-contained unit should never be placed
such that it can circulate carbon monoxide, fuel vapors
or other noxious fumes into the boat’s living spaces. Do
not install or operate a self-contained unit in the engine
room or near an internal combustion engine. Failure to
follow this precaution could result in serious injury or
death.

Selecting the Site

Self-contained units are designed for built-in installation low in
a closet, under a dinette seat or bunk, or any other convenient
location, with discharge air ducted to a grill high in the com
partment. See Figure 4 for a typical installation.

-

Ignition Protection Warning

Self-contained units do not meet federal requirements
for ignition protection. Do not install in spaces containing
gasoline engines, tanks, LPG/CPG cylinders, regulators,
valves or fuel line ttings. Failure to comply may result in
injury or death.

The self-contained unit must be mounted in a space large
enough to provide clearance on all sides for air circulation. It is
not necessary that the coil be placed directly behind the return
air grill, but an unobstructed path must be provided for the air
to get to the coil. A 2” (50 mm) space in front of the evaporator
coil must be maintained.

Measure carefully for horizontal and vertical clearance prior to
proceeding with installation. It is a good practice to place each
component physically in the area you have selected to ensure
that there is enough space and that connections can be easily
made.

Note that some Cruisair self-contained units have a detachable
electrical box, which can be remotely mounted to save space in
the installation.

-

Dedicated 50Hz units will give full performance at 50Hz, and
should be used when the system is going to be run exclusively

6

v

English

L-2086 Installation

Site Location Checklist

• Unit is not located in an engine room or near an internal

combustion engine

• There is no obstruction of airow from return air grill to coil

• Seawater can be piped to the unit with no loops, dips, or

kinks

• Accessible for service and maintenance, including the return

air lter

• Adequate space for seawater and condensate drain connec

tions

Flat, horizontal and sturdy mounting location

•

• Condensate drain can be run continuously downhill from

unit to overboard tting or sump

• Space is sealed from the bilge or outside air

Mounting the Self-Contained Unit

Before mounting the unit, rotate the blower for discharge in
the desired direction by removing the screws from the blower
mounting ange and any supporting the rear of the blower,
then replacing all screws and remounting the electrical box (if
needed).

Mount the unit on a horizontal surface, and fasten securely
with the hold-down clips provided. If the unit has a detachable
electrical box and you wish to mount it remotely, it should be
securely fastened to a bulkhead or deck.

Route the condensate drain so that it ows freely to an over
board tting or sump. Do not permit condensate to puddle in
the bilge
condensate drains, one at each end. It is recommended that
you use both drains for best results, but if you choose to use
only one condensate drain, place the included plug in the other
hole.

Once the unit is correctly mounted, proceed to section titled

“Installing The Seawater Cooling System.”

. Note that most Cruisair self-contained units have two

-

Installing The Condensing Unit

This section applies only to remote condensing unit systems. If
you are installing a self-contained unit, skip this section and go
to “Installing The Seawater Cooling System.”

Selecting the Site

Cruisair condensing units are designed to be installed in any
convenient location. The unit is normally placed in the engine
room or other machinery space, but it can be located in the
living areas. The condensing unit will produce condensation so
a drip pan may be needed. The space around the unit can be
insulated to reduce noise if desired. The unit is internally cooled
and does not require ventilation.

-

Ignition Protection Warning

Most Cruisair remote condensing units meet federal
requirements for ignition protection. However, there are
some condensing units, such as those with 3 -phase
compressors, that are not ignition protected. Do not
install non-ignition protected units in spaces containing
gasoline engines, tanks, LPG/CPG cylinders, regulators,
valves or fuel line ttings. Failure to comply may result in
injury or death.

Site Location Checklist

• Adequate space for access to refrigerant, and seawater and
electrical connections

• Accessible for service and maintenance

• Flat, horizontal surface

• Away from direct spray from engine air intakes or water
washdown

• Maximum refrigerant tube run is 50ft (15m)

Mounting the Remote Condensing
Unit

Orient the unit so the refrigerant, electrical connections and
service ports are accessible.

On models with a plywood base, simply drill 4 mounting holes
through the base in appropriate locations and fasten the unit
with screws or bolts. Do not remove the plywood base or shock
mounts as they are part of the vibration and noise isolation
built into the unit.

Some models utilize a drain pan with bottom or side conden
sate drains. Screw or bolt through all corner holes of the pan to
mount the unit.

Do not remove any covers, caps or ttings that may expose any
wiring or refrigerant. Only remove these items when you are
ready to complete the installation. Removal of any covers may
result in damage to the electrical components. Removal of the
caps or ttings may result in refrigerant loss.

-

7

v

English

L-2086 Installation

Installing The Cooling/Heating
Unit

This section applies only to remote condensing unit systems. If
you are installing a self-contained unit, skip this section and go
to “Installing The Seawater Cooling System”.

Safety Warning

A Cruisair cooling/heating unit should never be placed
such that it can circulate carbon monoxide, fuel vapors
or other noxious fumes into the boat’s living spaces.
Failure to follow this precaution could result in serious
injury or death.

Ignition Protection Warning

Cooling/heating units do not meet federal requirements
for ignition protection. Do not install in spaces containing
gasoline engines, tanks, LPG/CPG cylinders, regulators,
valves or fuel line ttings. Failure to comply may result in
injury or death.

Safety Warning

Do not terminate air handler condensate drain lines with­in 3 feet (1m) of any outlet of engine exhaust systems,
nor in a compartment housing an engine or generator,
nor in a bilge, unless the drain is properly connected to a
sealed condensate or shower sump pump. Exhaust and/
or bilge fumes can travel up a drain line and mix with the
return air blowing into living areas.

Selecting the Site

Because of the diversity of available cooling/heating units,
there is a great deal of exibility in selecting the location. Typi­cally the unit is located low in the cabin, with the discharge grill
as high as possib
from the return air for proper air circulation.

There are basically 2 types of cooling/heating units, draw­through and blow-through. Figures 5 and 6 show typical cool
ing/heating unit installations.

1

. Draw-through units typically have squirrel-cage blowers

that are strong enough to push air through ducting to the
discharge grill.

2. Blow-through units use a fan or blower to blow air across
the evaporator coil for direct discharge through a grill. The
discharge air from these units should not be ducted.

le for good cooling performance and away

-

It is not necessary for the evaporator coil to be placed directly
in front of the return air grill, but an unobstructed path must be
available for the air to get to the coil. A 2” (50mm) space in front
of the evaporator coil must be maintained.

Site Location Checklist

• Unit is not located in an engine room or near an internal
combustion engine

• There is no obstruction of airow from return air grill to coil

• Accessible for service and maintenance, including the return
air lter

• Adequate space for and condensate drain connections

• Flat, horizontal and sturdy mounting location

• Condensate drain can be run continuously downhill from
unit to overboard tting or sump

• Space is sealed from the bilge or outside air

• Maximum copper tubing run between condensing unit and
cooling unit is 50 ft. (15m)

Mounting the Cooling/Heating Unit

Mount the cooling/heating unit so that the condensate drip pan
is beneath the unit. Some models require a mounting frame or
mounting leg kit, which is supplied separately. Other models
have integral mounting frames or the condensate pan itself
is the mounting base. See individual spec sheets for specic
guidelines.

Route the condensate drain hose steadily downhill so that the
condensate ows freely to an overboard tting or sump. Do not
permit condensate to puddle in the bilge. Some Cruisair cool
ing/heating units have two condensate drains, one at each end.
It is recommended that you use both drains for best results. If
you choose to use only one condensate drain, plug the other.

Be careful when bending the extension tubes on the evapora
tors. Do not allow the tubing to kink and do not twist or bend
the tubing at the connection point close t
may crack. If bending by hand make large radius bends. Use a
tube bender if a tight bend is required.

o the coil or the joints

-

-

Installing the Refrigerant Tubing

Use refrigerant-grade soft copper tubing of the correct sizes to
connect the cooling/heating unit to the condensing unit. Note
that tee-joints will be needed if more than one cooling/heat
ing unit is used with a single condensing unit. The tees must
be properly oriented to provide best efficiency. (See Figure 7,
Refrigerant Line Size Chart.)

-

Some cooling/heating units are designed for overhead use,
and may be mounted below a ybridge console or seating. This
setup will draw return air through the overhead, with discharge
air either directly blown back down into the area or ducted to
overhead grills.

Only use refrigerant-grade seamless soft copper tubing. Never
use any type of plastic or rubber hose or tubing.

The refrigerant tubes can run uphill, downhill or sloping as re
quired and can have as many bends as necessary. Avoid sharp
bends that could result in kinks in the tubing. The cooling/heat-

8

-

v

English

L-2086 Installation

ing unit has additional tubing to help with installation. Take care
when bending this tubing as it can easily kink or crack a weld
joint resulting in refrigerant loss.

A self-draining seawater system will allow air in the piping to
rise naturally through the pump and then be expelled. It will
also make winterizing the system much easier.

Both refrigerant lines should be insulated individually.

When putting the recommended closed cell foam insulation
over the tubes, cover the ends of the copper tubes to prevent
foreign material and moisture from getting inside the copper
tubing. After checking for leaks, insulate the connecting are
nut joints and tee-joints to prevent secondary condensation.
Secure tubing every 3 feet (1m) as necessary for support.

The copper tubing is connected to the condensing unit and
cooling/heating unit with are joints. To prevent refrigerant
leaks, ares must be formed correctly with the proper aring
tool. Only 45-degree single ares should be used.

Flares should be made following the instructions of the partic
ular aring tool. Make sure to slide the are nut onto the tube
before aring. A drop of oil on the tube can ease the aring
process. The surface of the are face must be smooth and free
of defects to ensure that the joint won’t leak. The are should
be large enough in diameter to ll the are nut completely.

Once you have completed installing the cooling/heating unit
and have made the refrigerant connections between the cool
ing/heating unit and the condensing unit, proceed to on to the
next section “Installing The Seawater Cooling System.”

-

-

Installing the Seawater Cooling
System

The following installation instructions apply to both self-con­tained and remote condensing units.

Importance of a Self-Draining Sys­tem

Along with restricted ducting, a poorly plumbed seawater
system is one of the most common installation problems on
marine air conditioners. When water ow is lost, not only will
the air conditioning units no longer cool or heat, the units and
the pump could be damaged from running with no water ow.

When using a centrifugal seawater pump, it is imperative that the
seawater piping be routed continually uphill from the through-hull
inlet to pump and to the condenser, then smoothly up or down
to the overboard discharge, without any dips or loops, and with
only one high point in the system. This is said to be self-draining
because all water would drain out of the piping if the boat were
lifted out of the water.

Whenever air gets into the system, which can happen in heavy
seas or a sharp turn, it can become trapped in the pump.
Because a centrifugal pump cannot pump air, ow through the
system is lost.

Figure 8 shows a properly plumbed system and some common
mistakes.

Through-Hull Inlet Fitting

A separate through-hull tting must be installed for each air
conditioning seawater pump. Do not attempt to draw water from
an engine, generator, or other through-hull tting.

A scoop-type through hull should be installed facing forward,
and as far below the water line and close to the keel as possi
ble.

Drill a properly sized hole for the through-hull tting. Bed the
scoop with marine sealant designed for underwater use, and
tighten the nut onto the through-hull to secure it.

-

Seacock

A full ow seacock should be installed directly onto the
through-hull tting. Use Threaded-seal tape or other sealant on
the threads. The seacock must be accessible and easy to close
in case of emergency, or to clean the strainer.

Strainer

A seawater strainer must be installed between the seacock
and the pump, and should be situated to provide easy access
for cleaning. The strainer must be located vertically above
the seacock and below the pump so any air that gets into the
strainer can get out.

Make sure the water ow through the strainer is in the correct
direction. Some strainers have an arrow that shows correct ow
direction.

Mount the strainer to a bulkhead so it is properly supported
before connecting hoses. Use Threaded-seal tape or other
sealant on pipe threads.

Seawater Pump

Centrifugal pumps are not self-priming, and must be mount­ed so that they are below the heeled waterline in any given
operating condition. The pump should be accessible for future
service.

Mount the pump so the outlet is directed upward so air can
escape. The head on some pumps can be rotated to allow
mounting on a vertical bulkhead. See Figure 9.

Self-priming pumps are available if the pump cannot be mount
ed below the waterline.

Required seawater owrate is 4 gpm per ton
(12,000 Btu/hr) of total system capacity.

-

9

v

English

L-2086 Installation

Manifolds

If a pump is serving multiple units, then a seawater manifold
will be needed to supply water to all units. This can be as
simple as a TEE for 2 units, or a custom made manifold for up
to 7 or 8 units.

It is very important to consider manifold orientation so that all
air conditioning units get the proper ow of water. See Figure
10 for manifold information.

need to be larger than the outlet pipe size. Do not use
pump connections to determine hose size.

• The “Pump Inlet” recommended pipe size includes all

ttings and hose (through-hull, seacock, strainer, etc.) up to
the pump inlet connection. The “Pump Discharge” includes
all piping/hose and ttings from the pump to the air condi
tioning unit or manifold, and to the overboard discharge.

• Use larger hose when the run is longer than 16 feet (5m).

-

A manifold can also be used on the outlets of the air condition
ing units when using a single overboard discharge.

Overboard Discharge

The overboard tting should be located between 1 to 2 inches
(25 - 50 mm) above the water line. This is to facilitate visual
conrmation of water ow, but also close enough to the water
to minimize splashing noise.

If the overboard tting must be installed below the heeled water
line, then a valve must be installed per ABYC standards.

Seawater Piping

• Only use reinforced marine grade hose or other suitable
piping (PVC, CPVC, Cupronickle, or Stainless steel).

• Double clamp all hose connections.

• Use only plastic, bronze, or stainless steel ttings (do not
use brass).

• Avoid loops or dips in the hose runs.

• Make sure enough hose is used to allow future removal of
components.

-

Bonding

Bond all metallic parts (through-hull ttings, valves, strainer,
manifolds, etc.) that are in contact with seawater to the vessel’s
bonding system in accordance with ABYC standards E-8 and
E-9. Items should only be bonded or grounded once. If an item
is in contact with an electrically grounded part (pump head or
seawater condenser) then it should not be bonded again.

Installing The Air Distribution
System

The following instructions apply to both self-contained units
and remote condensing systems, except as noted. Refer to
Figure 11 for proper grill and duct sizes.

Return Air Grill (RA Grills)

The return air grill should be located so there is unobstructed
airow to the unit’s evaporator coils. Installing ducting between
the return air grill and the air conditioning unit is not normally
necessary and should be avoided. The grill may be located on
a side opposite the evaporator coil so long as airow to the coil
is unobstructed.

• Use the correct size hose, ttings, and components. See
the table below for proper seawater sizing. Note that the
pump inlet piping (including through-hull and strainer) may

An air lter must be used to prevent the evaporator coil from
collecting dirt and lint. The lter can be located at the evap
orator coil or at the grill. Only one lter should be used. Most
self-cont
lter, but if the lter is not easily accessible, use a lter on the
return air grill.

ained units and cooling units are supplied with an air

Ducts

Insulated exible ducting or built-in ducting may be used to
route air from the blower to the discharge grill. Note that blow
through cooling units are installed directly behind the discharge
grill, and ducts are unnecessary. Likewise, with some overhead
cooling/heating units, air is discharged directly into the com
partment without ducts.

Ducting Guidelines

Secure duct to blower or transition box (plenum) with screws
and duct tape. When using insulated exible ducting, make
sure inner duct is secured and sealed to adapter before pulling
insulation over connection.

10

-

-

v

English

L-2086 Installation

Plenums, or transition boxes are used with exible ducting to
split and route the discharge air as needed. Figure 12 shows
several plenum congurations.

• Ducting must be properly sized for the airow. If the duct run is

longer than 10 feet (3m), use the next larger duct size.

• Use of insulated duct is recommended, and is mandatory
when used in high heat areas or where condensation would
be a problem.

• Run exible ducting tightly and smoothly, with as few bends
as possible.

• Keep ducts as short as possible.

• Support ducting to prevent sagging during boat operation.

• Trim excess ducting before attaching to transition adapters.

• Make sure ducting is not crushed or kinked.

• Use a exible transition duct between blower and any built­in ducting.

• If possible, rotate blower to keep duct run as short and
direct as possible.

Discharge Air Grill

When used with exible ducts, a grill plenum should be incor­porated behind the discharge grill. Location of this grill should
be as high as possib
ow between discharge and return encompasses as great an
area as possible in the cabin. Care should be taken to avoid
“short cycling,” a situation where the conditioned air is returned
to the coil without being substantially affected by the cabin air.

le in the cabin, and oriented so that air

Installing the Control Unit

The SMX Control

If your system has SMX controls, refer to the appropriate SMX
II or SMX Net Control System Installation/Operation Manual.

be rear access with sufficient clearance for the wiring and the
protective cover. The thermostat bulb is on a 10 ft (3m) long
capillary tube, and the switch assembly must be installed close
enough to the unit so the bulb can be mounted in the return air
path.

Remote condensing systems use SA type switches which
have terminal strips that must be mounted to the back of the
bulkhead where all eld wiring terminates. This location must
be easily accessible for wiring connections and service.

One and two-knob slave switch assemblies should be installed
in the cabin where the slave cooling unit is operating.

Mounting

Cut a hole in the bulkhead using the template shipped with the
switch, or one from the back of this manual. See Figures 13a
and 13b for templates and switch dimensions.

Attach the terminal strip to an accessible location on the back
of the bulkhead (remote systems only). Self-contained systems
have a 10-foot (3m) harness with a plug that connects to the
self-contained unit.

Carefully route the thermostat bulb from the switch to the
return air path of the unit so the capillary tube does not get
kinked. The large bulb must sense the return air, and not touch
the evaporator coil. If a second smaller “anticipator” bulb is
attached to the main bulb, it should be installed into the dis
charge duct.

After making all wire connections, install the protective plastic
cover (remote systems only) over the terminal strip. Next install
the plastic cover over the back of the switch assembly (remote
and self-contained systems) and mount the switch to the bulk
head with the 4 screws provided.

-

-

Installing the Pump Relay

The Rotary Knob Switch Assembly

The following instructions apply to both self-contained and
remote condensing unit systems using a rotary-knob switch
assembly.

Warning

The rotary knob switch assembly switches line voltage
(115 or 230VAC) and in many case full power of the unit.
The selected mounting location must be safe in regards
to voltage as well as heat produced by the switch as­sembly.

Location

The switch assembly should be mounted on a vertical bulk­head where it can easily be seen and reached. There should

The following instructions apply to both self-contained and
remote condensing unit systems that have multiple A/C units
served by a single seawater pump. If you only have one A/C
unit, or each unit has it’s own seawater pump, then skip to the
next section.

Location

The pump relay is generally located in the engine room near
the seawater pump, but it can be mounted anywhere that is
convenient and accessible. It must be in a dry location, away
from any possible water spray, with room for some heat dissi
pation.

11

-

v

English

L-2086 Installation

Warning

PR3X and PR8X pump relays are certied ignition
protected. However, pump relays with electromechanical
relays or contactors (such as 3-phase pump relays) are
not ignition protected and must never be installed in
spaces containing gasoline engines, tanks, LPG/CPG
cylinders, regulators, valves or fuel line ttings. Failure to
comply may result in injury or death.

Voltage and Triggers

PR3X and PR8X pump relays are identical in operation. When
the rst A/C unit turns on, the pump relay will turn on the sea­water pump, and the pump will stay on until the last A/C unit
shuts do

The PR3X can operate up to 3 A/C units, and the PR8X can
operate up to 8 A/C units. Both can operate 115V and 230V
pumps.

Triggers are used in the pump relays to isolate the signals from
each A/C unit. Some pump relays come with pre-installed trig
gers, or you can buy triggers separately. Triggers come in 115V
and 230V
Both 115V and 230V triggers can be used in a single pump
relay if the system requires it.

wn.

-

, and must match the control voltage of the A/C unit.

• If there is only one a/c unit, the seawater pump does not re
quire a separate breaker, but make sure the breaker is siz
for the combined load of the unit and the pump. If multiple
a/c units are supplied by a single pump, then a pump relay
will be needed, and will require it’s own circuit breaker.

• All units must be grounded to minimize the potential hazard
of electrical shock and personal injury.

• All metallic ttings in the seawater system that are isolated
from the a/c unit or pump by rubber hose should be bonded
per ABYC standards E-8 and E-9.

• On larger F-type condensing units a fuse can be added to
protect the fan and control wires.

-

ed

The trigger is simply a relay that closes when the A/C unit turns
on. Because each trigger is isolated, the polarity of the signals
from the A/C units does not matter.

Electrical Connections

Warning

Make sure all power is off before opening any
electrical box.

The following guidelines apply to both self-contained and
remote condensing unit systems:

• Failure to properly ground and bond the system will void
warranty.

• All electrical connections should be made within the
electrical junction boxes supplied with the units. Most units
have terminal strips that are labeled or have color-coded
wiring. Open terminal strips (such as supplied with switch
assemblies) require that the included terminal strip covers
be installed over the strip and switch back after installation
is complete.

• Wiring diagrams are included in the back of this manual and
under the cover of the electrical boxes on all units. Contact
Dometic Corporation if you are not sure if you have the
correct diagrams.

• Each air conditioning unit requires it’s own dedicated circuit
breaker, of the appropriate size. See the table below for
suggested circuit breaker and wire sizing.

Note

Always follow ABYC guidelines or local codes when selecting
breakers and wire sizes.

Three Phase Power

Some larger compressors and pumps have 3 phase motors
that will run forwards or backwards depending on the wire
connections. Reciprocating (piston type) compressors can run
either way without any problem, but scroll compressors and
centrifugal pumps are direction sensitive and must be wired
so the motors run the correct direction. If running backwards,
Scroll compressors will usually make loud, unusual noises and
will not perform properly.

12

v

English

L-2086 Installation

Safety Warning

To prevent a possible electrical shock in the event a
component has an electrical breakdown, which could re­sult in serious injury or death, always ground the system
in the following manner:

• Use proper wire size with a ground to feed power from the
ship’s electrical panel to each cooling unit junction box.
Make sure the ground wire is properly connected to the
ground buss in the ship’s service distribution panel and to
the ground lug in the cooling unit’s junction box

• Connect the junction box ground lug to the P/L box green
wire (or to the switch assembly terminal strip).

• Use proper wire size with a ground to feed the power from
the ship’s electrical panel to the condensing unit’s junction
box. Make sure the ground wire is properly connected to the
ground buss in the ship’s service distribution panel and to
the condensing unit’s ground lug.

• Ground the seawater pump, and pump relay (if used) to the
condensing unit’s ground lug.

• Bond the ground lug on the condensing unit to the ship’s
grounding system.

• Check the continuity of the ground system before the system
is energized.

Inspecting the Self Contained Unit

• Is the air conditioning unit securely mounted?

• Is the unit located so that it will not draw fumes from the
engine room and discharge them into the compartment?

• Are condensate drains properly routed to an overboard
discharge or sump?

• If only one condensate drain is being used, has the hole at
the other end of the tray been plugged?

Inspecting the Condensing Unit

(Remote Condensing Unit Systems Only)

• Is the condensing unit mounted securely using the integral
wooden baseboard or drain pan?

• Are the fasteners accessible if it is necessary to remove the
unit for service later?

Inspecting the Cooling/Heating Unit

(Remote Condensing Unit Systems Only)

• Is the unit securely mounted?

• Are condensate drains properly routed to an overboard
discharge or sump?

• If only one condensate drain is used, have any other drain
holes in the drip tray been plugged?

Note

Always follow ABYC guidelines or local codes when selecting
breakers and wire sizes. ABYC standards are available from:
American Boat and Yacht Council, 3069 Solomon’s Island Rd.,
Edgewater, MD 21036, Telephone: [phone].

Final Inspection

Prior to charging or energizing the system, conduct a nal
inspection, using the following checklist.

Inspecting the Seawater Cooling
System

• Is the seawater pump properly sized for the system?

• Is the pump oriented correctly and mounted securely with
the pump outlet directed vertically upwards?

• Is the centrifugal seawater pump located so it is below the
water line at all times?

• Are the inlet and outlet thru-hulls secure, properly sealed
and properly oriented?

• Are all hose clamps tight?

• Are seawater hoses double clamped?

• Are there any loops or dips in the seawater plumbing that
might cause the system to become air locked?

• Is the strainer located between the seacock and the pump,
and is it correctly oriented?

• Are all metallic seawater ttings properly bonded?

Inspecting the Refrigerant Connec­tions

Only)

• Are are joints made with forged are nuts and properly

• Are are joints and tees properly insulated?

• Are copper refrigerant tubes individually insulated?

• Are tubes fastened securely to the boat every three feet or

(Remote Condensing Unit Systems

tightened?

as needed throughout their length?

Inspecting the Air Distribution Sys­tem

• Is there unobstructed airow from the return air grill to the
coil?

• Is there a lint screen or lter in the return air path where it is
accessible for regular cleaning?

• Have exible ducts been pulled tight to remove bends and
constrictions?

• Are grills correctly sized for the system?

13

v

English

L-2086 Installation

Inspecting the Control/Switch As­sembly and Electrical Wiring

• Is the thermostat sensor or thermistor properly located and
secured in the return air path and not in direct contact with
any metal objects? (For switch assemblies with two sensing
bulbs, the large one goes in the return air path and the small
one in the discharge air path.)

• Are all wiring harnesses properly secured?

• Are wiring connections made, color to color, correctly at
terminal strips?

• Are plugs properly aligned and securely connected?

• Are all components properly grounded and bonded?

• Are proper sized circuit breakers used?

• Are terminal strips located in a dry, safe place and properly
covered?

You will need the following tools to complete the
charging procedure:

• R-22 container (typically the disposable-type container
color-coded green for R-22)

• four-valve gauge manifold with self-closing ttings on the
charging hoses

• vacuum pump

• base valve wrench and hand tools

• accurate thermometer

Proceed as follows:

1. Make sure all are joints are well made and tight.

2. Do not touch the condensing unit base valve stem covers

or white port caps. Remove the red port cap on the dis
charge (right side) base valve (or on a eld-inst
tee tting).

-

alled in-line

Charging the System with Re­frigerant

Self-contained units are precharged from the factory and do not
need further charging. If you are installing a self-contained system,
skip this section and proceed to “Initial Startup”.

The following instructions should be followed in evacuating and
charging a Cruisair remote condensing unit system with R-22.
Some special ordered units contain refrigerant other than R-22.
Please follow the special charging procedures included with
the unit.

Notice

US federal law prohibits the intentional release of refrig­erant gases into the environment, including the R -22 re­frigerant used in most Cruisair air conditioning systems.
Special care must be taken when installing, charging,
and servicing Cruisair equipment to prevent any loss of
equipment. Only EPA certied technicians with the prop­er equipment should perform service on the refrigerant
circuit of the system.

Charging a New System

There are three refrigerant circuit components in a Cruisair re­mote condensing unit system: the condensing unit, the cooling/
heating unit and the copper r
unit is shipped from the factory charged with approximately the
right amount of refrigerant needed for the whole system.

The procedure will be to evacuate the nitrogen and air from the
cooling unit and the copper tubing, then release the refrigerant
from the condensing unit into the entire system. To facilitate
this procedure, there is a special evacuation port (red cap)
located on the base valve of the condensing unit .This port has
a schrader valve so you can evacuate and vapor charge the
lines and cooling unit without releasing the refrigerant in the
condensing unit.

efrigerant lines. The condensing

3. Connect the vacuum pump hose to the vacuum pump.

Connect the refrigerant supply line to the refrigerant
container (making sure the refrigerant container valve is
OFF). Connect the low pressure gauge hose, to the red
capped port. At this point, do not connect the high pressure
charging hose to anything.

4. Close all four gauge manifold valves.

5. Energize the vacuum pump and open the manifold valves

for the vacuum pump, the refrigerant container and the red­capped access port.

6. As the pump operates, you will see the low pressure test

gauge fall to a vacuum. When the vacuum reaches 28
in. Hg close the vacuum pump valve and turn the vacu
um pump off. Leave the system for 15 minut
observe the gauge. If any vacuum has been lost, look
for leaks, especially at are joints. Then return to step #3
above and re-evacuate the system.

7. Open the vacuum pump valve and leave the vacuum pump

operating for at least 6 hours, until a vacuum of at least 29
in. Hg is achieved. Close the vacuum pump valve and turn
the vacuum pump off. Wait one hour. If no vacuum is lost,
proceed with charging. If any leaks are indicated, reinspect
are joints for leakage, and return to step #3 above to
re-evacuate the system.

8. Open the refrigerant container valve slowly and allow gas

to enter the system until the low pressure gauge rises to
zero. You have now vapor charged the evacuated lines and
cooling/heating unit with refrigerant to a gauge pressure of
zero. Close the refrigerant container valve.

9. Remove the low pressure gauge hose from the red capped

port. Replace and tighten the red cap.

es and then

-

14

v

English

L-2086 Installation

10. Remove both condensing unit base valve stem caps. Open
both base valves fully by turning the valve stems fully coun­terclockwise. This will allow the refrigerant in the condens­ing unit to enter the system. Replace and tighten the valv
stem caps.

At this point, the system is basically charged and ready for nal
gas charge adjustment once the boat is in the water.

e

Field Charging the System

To eld charge a new unit, which has been evacuated and
basically charged, proceed as follows:

1. Remove both base valve stem caps and conrm that both
valve stems are in the back-seated or full counterclockwise
position.

2. Remove the white gauge port caps from both base valves.
No gas should escape. If it does, retighten the cap and call
Dometic Corporation for assistance.

Removing Refrigerant from the Sys­tem

When adjusting the charge in the refrigerant system, you may
have to remove refrigerant. It is a violation of federal law to
vent refrigerant to the atmosphere, and it is necessary that you
capture any refrigerant that is removed from the system. There
are two methods of doing this.

1. Use an approved refrigerant recovery unit and rellable
refrigerant container.

2. Allow refrigerant to escape from the high pressure side into
a rellable refrigerant container.

Initial Start Up

The following instructions apply to both self-contained and
remote condensing systems.

3. Close all gauge manifold valves.

4. Attach the gauge manifold hoses to the gauge ports: high
pressure on the right and low pressure on the left. Connect
the hose to the refrigerant container.

5. Open both base valves to the test position by rotating the
stems one turn clockwise.

6. Start the unit in the cooling mode, and observe the system
pressures. Use the charging curves shown in Figure 29
to determine the proper pressures. These charts are to
be used as a GUIDE to setting pressures. They are NOT
designed to give EXACT pressure settings. There are
conditions that may cause pressures to vary. Head pres
sures may vary +10%.
Accurate Suction Pressure settings are more critical f
proper functioning of the system. Through the gauge
manifold, adjust the gas charge to obtain the proper system
pressures.

7. To remove the gauge manifold, backseat the base valves
by turning the stems fully counterclockwise. Tighten the
stem packing gland nuts. Replace and tighten the stem
caps. Remove the gauge hoses and replace and tighten
the port caps.

-

or

1. Open the seacock (seawater inlet valve).

2. Turn on the circuit breaker for the air conditioner. If a pump
relay is installed, the breaker for the pump must also be
turned on.

3. Following directions in the Operation manual, set the
system for cooling or heating at the switch or SMX keypad,
and adjust temperature setting so the unit will turn on.

4. Verify that water is owing from the overboard discharge.
Check all overboards if more than one unit is installed.

5. Allow unit to run for 10 minutes at high fan speed. Check
the temperature differential between discharge and return
air by placing an accurate thermometer in front of the dis
charge grill and then in front of the return air grill.

In cooling, the difference between the discharge and return
should be 15 - 20°F (8.3 - 11.1°C), with normal ambient air
and water temperatures. In the heating mode the differen
tial can be as high as 25°F (13.9°C).

If e

verything checks out, the system is ready to go.

-

-

Note

It is recommended to charge the system in the cool mode (as
described above). If conditions are such that charging must
be done in the heat cycle, the gauge connections must be re
versed on the base valves. Also note that in the heat mode the
same pressures can be observed at two different charge levels.
This could lead to an overcharge condition.

-

15

v

English

L-2086 Operation

DX Remote & Self-Contained A/C Systems • Operation

Operating Instructions - Rotary
Controls

SA & SSA Models

1. Open the seawater inlet valve.

2. Set the OFF -

3. Turn on the main circuit breakers on your boat’s electrical
panel designated for the air conditioning unit. If there is
more than one air conditioning system on board, you must
also turn on the breaker for the seawater pump.

4. Set the thermostat by turning the
COOLER) to the desired mode of operation.

5. Set the fan speed control to

6. Turn the top control knob to

7. Turn the top control knob to ON. The compressor will start,
and the unit will begin to cool or heat, depending on which
mode of operation you have selected. Verify that water is
owing from the overboard discharge.

8. To set the thermostat, allow the unit to operate until the
area is cooled or heated to the desired temperature. At

this point, turn the
toward the center position until you hear it “click” once. The
thermostat is now set to maintain the desired temperature.

9. Set the fan speed to provide the desired ow of air, using
the center knob.

10. If you turn the system off, or if you wish to switch between
cooling and heating, wait three minutes to allow the sys
tem’s internal pressures to equalize before attempting t
restart.

- ON knob to the OFF position.

knob (WARMER/

(HIGH).

to energize the blower.

knob (WARMER/COOLER) slowly

-

o

SMX II/SMX Net Operation

1. Open seacock (seawater inlet valve).

2. Turn on main circuit breakers for the air conditioning sys­tem. If there is more than one unit on board, you m
turn on the breaker for the seawater pump.

3. Adjust SMX settings as desired.

ust also

Hint

It is good practice to check for seawater ow by observing the
overboard discharge when the system is rst turned on. If you
do not observe steady water ow, shut the system down and
check the seawater system.

Power On

When AC power is applied to the system at the circuit breaker,
the SMX microprocessor retrieves from permanent memory
the last operating conguration. This process takes about four
seconds, after which the system will begin operating just as it
had been when power was last turned off.

System Off

Press the OFF key to turn the system off. Note that the data
display remains energized even when the system is off. The fan
can be turned on manually when the system is in the off mode.

Note

The SMX has built-in protection against sudden power interrup­tions. The system automatically stores the current operating
congur
changes. (The new operation mode must be in affect for 10
seconds before it is saved into permanent memory.) When AC
power is lost, the SMX system retains these settings, and when
AC power is restored it resumes operation using the same
settings as before.

ation in permanent memory every time you make

Hint

It is good practice to check for seawater ow by observing the
overboard discharge when the system is rst turned on. If you
do not observe steady water ow, shut the system down and
check for obstructions in the seawater cooling system.

Operation Instructions - SMX
Controls

There are two different SMX control systems available, SMX II
and SMX Net. The following are basic operation instructions for
both systems. For complete installation and operation infor
mation, consult the appropriate manual, L-2066 for SMX II or
L-2067 for SMX Net.

Selecting Setpoint

Press the SET key and the current setpoint will be displayed.
Press the UP or DOWN key to change the setpoint.

Displaying Temperature

To display cabin temperature, press the TEMP key.

SMX II Only

Press TEMP a second time for an alternating display of inside
temperature and setpoint. Press a third time to return to inside

-

temperature only.

16

v

English

L-2086 Operation

SMX Net Series

If your boat is equipped with the optional outside thermistor,
press TEMP a second time to display outside temperature.
Press a third time for an alternating display of setpoint, inside
temperature and outside temperature. Note that the inside
and outside indicators show you which temperature is being
displayed.

Cool Mode

To enter the COOL mode, press the COOL key. The Cool Mode
Indicator will light to show that you have selected the cooling
mode.

The Cooling Indicator will be lit whenever the system is in the
cooling mode and the compressor is actually running. When
the compressor cycles off, the Cooling Indicator goes off, but
the Cool Mode Indicator stays on.

Heat Mode

Press the HEAT key to select HEAT Mode. The Heat Mode
Indicator will light to show that you have selected the heating
mode.

The Heating Indicator will be lit whenever the system is in the
heating mode and the compressor is actually running. When
the compressor cycles off, the Heating Indicator goes off, but
the Heat Mode Indicator stays on.

Automatic Changeover

Press the COOL and HEAT keys simultaneously for AUTO­MATIC CHANGEOVER between COOL and HEAT Modes.
The mode indicat
automatic changeover mode.

For the SMXir Remote Control only - Press the Auto Switchover
key to enter automatic changeover mode.

Note that the Cooling or Heating Indicator will come on when
the compressor is running to show when the system is running
in the cooling or heating mode.

ors will light, to show that the system is in the

Manual Fan Speed Control

Press the FAN key to select manual fan control. The Manual
Fan Indicator will light to show that it is in the manual mode.
Then use the SLOW and FAST keys to select the desired fan
speed.

Note that you can use the manual fan control to circulate air
even when the system is in the OFF mode.

speed automatically slows. Once setpoint is reached, the com
pressor cycles off and the fan keeps running on low speed.

-

Adjusting Brightness

Pressing the SET key repetitively will dim the LED display.
Keep pressing SET to return to full brightness.

Note

SMXLB keypads automatically adjust according to cabin light­ing.

Using The Humidity Control Rou­tine

When engaged, the SMX humidity control routine automati­cally turns the air conditioning system on at timed intervals to
r

emove moisture from the air. The system is programmed at the
factory for average values. To change the factory settings, see
“Humidity Control Program”.

To start the dehumidication program:

• Press OFF.

• Press COOL, HEAT and FAN keys simultaneously.

For the SMXir Remote Control only - Pr
key to enter dehumidication mode.

• The data display will ash HU, indicating that the program is

active.

• To halt the dehumidication program, press any key. The

HU message will stop ashing.

ess the Dehumid

Safety Note

Whenever the SMX system is in the dehumidication mode, all
of the system safeguard controls remain active. If the seawater
ow fails or if line voltage falls below preset limits, the system
will automatically shut down. If AC power is interrupted, the
system will automatically resume operation in the dehumidica
tion mode when power is restored.

Anti-Ice Routine

The SMX control will occasionally shut down the compressor in
the cooling mode to allow any ice that may have formed on the
evaporator coil to melt. The anti-ice shutdown only occurs at
inside temperatures lower than 70°F (21°C).

In a 10 minute cycle period, the compressor will shut off for
15 seconds per degree (°F) below 70°F. For example, if the
inside temperature is 67°F, the compressor will shut off for 45
seconds every 10 minutes.

-

Automatic Fan Speed Control

If in manual fan mode, press FAN key to select automatic fan
control. The Manual Fan Indicator goes off, and the system will
automatically adjust fan speed as the actual cabin temperature
deviates from the setpoint. As setpoint is approached, the fan

17

v

English

L-2086 Operation

Owner Maintenance - Routine

Condensate Drains

Every three months, check the condensate drains for obstructions
by pouring a quart of water rapidly into the condensate pan. If
it does not drain completely within 30 seconds, check the drain
outlets for clogging. Remember that many Cruisair systems have
two drains and hoses, one at each end of the unit.

Air Filters

At least once a month, check the lint screen or lter behind
the return air grill or on the face of the cooling/heating unit and
clean if necessary.

The unit will not operate at all.

Solution

1. Blown fuse or tripped circuit breaker. Replace fuse with

time delay type or reset breaker. Check for correct sizing.

2. Low voltage to unit. Check shoreside power supply and

rating of electrical power cord to boat.

Situation

Air from the unit does not feel cool (or warm in the heating
mode).

Solution

1. The selector switch is set for FAN only. Switch the system

into the cooling or heating mode.

Seawater Connections

Verify that all seawater connections are tight, and check for
water ow from each unit’s overboard discharge.

Seawater Pump

If your system uses a rubber-impeller seawater pump, you
should inspect the impeller after 300 hours of operation.
Replace it if worn. If you have a centrifugal pump, regular main
tenance is not needed.

Seawater Strainer

Check the seawater strainer daily. Remove any debris.

Refrigerant Gas

The refrigerant gas (most likely R-22) used in your Cruisair
air conditioning system is adequate for the life of the system.
Routine “seasonal” charging of the system is not typically
necessary.

Winterizing the System

Close the seacock and remove the inlet water hose from the
air conditioner. Allow all water to drain from the system. Loosen
the screws on the pump head to allow the water to drain from
the pump. Drain and clean the seawater strainer.

Trouble Shooting

Before you call for service, review this list. It may save you time
and expense. This list contains common occurrences that are
not a result of defective workmanship or materials. If you need
service after trying these procedures, call your nearest Cruisair
dealer.

2. The thermostat is set incorrectly. Set the thermostat for a

cooler or warmer setting.

3. Water ow is restricted. Clear restriction. Clean strainer.

Situation

The unit operates but the cabin fails to cool normally.

-

Solution

1. Dirty air lter. Clean lint screen or air lter.

2. The thermostat is set too high. Reset the thermostat to a

cooler setting.

3. The evaporator has iced. Turn the system to FAN only for 5

minutes, then restart.

Situation

Compressor cycles on and off.

Solution

1. Dirty air lter. Clean lint screen or air lter.

2. Water ow restriction. Clear restriction. Clean strainer.

Situation

Water dripping inside cabin.

Solution

1. Condensate drain is clogged. Clean out drain holes.

2. Blockage in hose. Clear hose. Check downhill routing of

hose.

Situation

18

v

English

L-2086

Descriptions of Figures

Fig. 1 Typical Self-Contained Unit
Fig. 2 Typical Remote Condensing Unit
Fig. 3 Typical Draw-Through Cooling Unit
Fig. 4 Typical Self-Contained Installation
Fig. 5 Typical Draw-Through Cooling Unit Installation
Fig. 6 Typical Blow-Through Cooling Unit Installation
Fig. 7 Refrigerant Line Sizes
Fig. 8 Seawater Piping, Proper System and Common Mistakes
Fig. 9 Pump Head Orientation
Fig. 10 Seawater Manifolds
Fig. 11 Duct and Grill Sizes
Fig. 12 Plenum Congurations
Fig. 13 Switch Dimension and Templates
Fig. 14 SHR5-16 StowAway Wiring, #082611
Fig. 15 SH24C StowAway Wiring, #080264
Fig. 16 SHF5-16-C StowAway Compact w/ 3-knob Control Wiring
Fig. 17 SHF24-C StowAway Compact w/ 3-knob Control Wiring
Fig. 18 SHUF18(C/CK)/1-HV StowAway Compact w/ 3-knob Control Wiring
Fig. 19 SHUF5-16(C/CK)/1-HV StowAway Compact w/ 3-knob Control Wiring
Fig. 20 WFAH6-16 Condensing Unit Wiring, #082201
Fig. 21 R/F20-60C 1-Ph. Cond. Unit Wiring, #082534
Fig. 22 R/F24-72 3-Ph. Cond. Unit Wiring, #082556
Fig. 23 SA3-Z Switch Wiring
Fig. 24 SA5-Z Switch Wiring
Fig. 25 PR3X Pump Relay Wiring
Fig. 26 PR8X Pump Relay Wiring
Fig. 27 WFAH System Wiring, 115V
Fig. 28 WFAH System Wiring, 230V
Fig. 29 WFAH System Wiring, 230V, w/ Aux. Heat
Fig. 30 R/F Type System Wiring, SA3-Z Switch, 1Ph.
Fig. 31 R/F Type System Wiring, SA3-B Switch, 1Ph.
Fig. 32 R/F Type System Wiring, SA3-Z Switch, 3Ph.
Fig. 33 Refrigerant Charging Curves (R22)
Fig. 34 Charging Systems with Alternative Refrigerants

19

Fig. 1 - Typical Self-Contained Unit

Fig. 4- Typical Self-Contained Installation

Fig. 2 - Typical Remote Condensing Unit

Fig. 3 - Typical Draw-through Cooling Unit

Fig. 5 Typical Cooling Unit Installation (draw-

through)

Fig. 6 Typical Cooling Unit Installation (blow-

through)

L-2086

20

Fig.7 - Refrigeration Line Sizes

Notes:

• Maximum length of refrigerant line between condensing unit and
cooling unit is 50 feet (15m).

• Only use seamless refrigeration grade copper tubing.

• Insulate discharge and suction tubes separately.

• Use minimum 3/8” (10mm) thick closed cell insulation.

• Seal (glue and/or tape) all insulation seams.

• Use “dead-head” orientation of TEEs on multiple cooling unit sys
tems to help ensure proper distribution of refrigerant.

-

L-2086

21

Fig. 8 - Seawater Piping - Proper System and Common Mistakes

Fig.10 - Seawater manifoldsFig. 9 - Pump head orientation

L-2086

22

Fig. 12 - Plenum CongurationsFig. 11 - Duct and Grill Sizes Tables

L-2086

23

Fig. 13a - Switch Dimensions and Templates

L-2086

24

Fig. 13b - Switch Dimensions and Templates

L-2086

25

Fig. 14 - SHR5-16 StowAway Wiring, #082611

Fig. 15 - SH24C StowAway Wiring, #080264

L-2086

26

Fig. 16 - SHF5-16-C StowAway Compact w/ 3-knob Control Wiring

Fig. 17 - SHF24-C StowAway Compact w/ 3-knob Control Wiring

L-2086

27

Fig. 18 - SHUF18(C/CK)/1-HV StowAway Compact w/ 3-knob Control Wiring

Fig. 19 - SHUF5-16(C/CK)/1-HV StowAway Compact w/ 3-knob Control Wiring

L-2086

28

Fig. 20- WFAH6-16 Condensing Unit Wiring, #082201

Fig. 21- R/F20-60C 1-Ph. Cond. Unit Wiring, #082534

L-2086

29

Fig. 22- R/F24-72 3-Ph. Cond. Unit Wiring, #082556

Fig. 23- SA3-Z Switch Wiring

L-2086

30

Fig. 24- SA5-Z Switch Wiring

Fig. 25- PR3X Pump Relay Wiring

L-2086

31

Fig. 26- PR8X Pump Relay Wiring

Fig. 27- WFAH System Wiring, 115V

L-2086

32

Fig. 28- WFAH System Wiring, 230V

Fig. 29- WFAH System Wiring, 230V, w/ Aux. Heat

L-2086

33

Fig. 30- R/F Type System Wiring, SA3-Z Switch, 1Ph.

Fig. 31- R/F Type System Wiring, SA3-B Switch, 1Ph.

L-2086

34

Fig. 32- R/F Type System Wiring, SA3-Z Switch, 3Ph.

L-2086

35

Fig. 33- Refrigerant Charging Curves (R22)

L-2086

36

Fig. 34 Charging Systems with Alternative Refrigerants

New A/C units are available from the factory with non-HCFC refrigerants.
R-417A (also known as NU-22® or Isceon 59®) is a direct drop-in replace­ment for R22. It will work with Alkyl Benzene and mineral lubricants so
standard compressors can be used. Note that some self-contained units
(with rotary compressors) and chillers (with scroll compressors) might have
R-407C with POE lubricant.

Both R-417A and R-407C are blended refrigerants, meaning they are made
up from multiple component refrigerants. In most cases the user will not
notice a change in operation or performance of these systems, but charging
a system with a blend requires some special considerations.

• We currently don’t have charging curves for either gas. A system with a
blend must be charged by superheat.

• The system should be charged with liquid refrigerant from the tank to
prevent fractionation. Note that some tanks have a dip tube so the tank
is used in the upright position, while other tanks will need to be turned
upside down to get liquid. This should be clearly marked on the tank.

• A partial leak in the system doesn’t necessarily mean that the refrigerant
needs to be removed and recharged. However, it is possible that enough
fractionation can occur that would require a complete evacuation and
recharge. This will be evident when trying to charge the system and the
temperature/pressures will not respond correctly.

To charge a split system with a blend:

1. Evacuate lines and evaporator (cooling unit) as normal.

2. Open base valves to release the refrigerant in the condensing unit.

3. Attach an accurate thermometer or temperature sensor to the suction
line near the base valve, at the 3 or 9 o’clock position on the line. Insu
late over the sensor so that the ambient temperature does not aff

.

reading

4.

Open the suction base valve to the test position. The low-side gauge

should now register a pressure reading.

5. Turn on the system in the cooling mode, and set the thermostat to a low
setting so the unit will stay on.

6. Allow the system to run for ve minutes so the pressures will stabilize,
then measure the superheat. This must be done using the Dew Point for
conversion.

Note: There is no ideal superheat temperature. It should be in the range
of 10° to 20°F (5.6° to 11.1°C), depending on the heat load. On cool
days, superheat will be lower, and on hot days it will be higher.

7. To reduce superheat, slowly add liquid refrigerant to the suction line. Do
this in very small increments and allow the system to stabilize before
taking another reading. DO NOT OVERCHARGE! If the system is
overcharged, refrigerant must be removed from the liquid line, using an
approved recovery cylinder.

Warning: You are charging with liquid refrigerant. To prevent liquid from
“slugging” the compressor, open the manifold valve only a small amount
to allow the refrigerant to ash from liquid to vapor in the charging hose.
GO SLOWLY! A special valve is available for charging liquids.

8. Once the superheat is set properly, close the manifold gauge valves,
and backseat the discharge base valve. Tighten the stem packing nuts,
remove manifold gauges, and replace service port caps.

-

ect the

Glossary

Blend - A refrigerant that is made up of two or more single-component
refrigerants.

Fractionation - Change in the composition of a blend because one (or
more) of the component refrigerants is lost (or removed faster than the
others). This happens because the components have different boiling
points. It can occur in a tank or system that has lost gas, or locally in a
system component such as a coil or accumulator.

Temperature Glide - Because of the different boiling temperatures of
the components, a blend will evaporate over a range of temperatures
(at a constant pressure). The difference between the Bubble Point and
the Dew Point is the Temperature Glide.

Superheat - The “extra” heat (beyond what is required to fully evap­orate the refrigerant) that the refrigerant picks up in the evaporator.
Superheat is determined by measuring the refrigerant temperature (at
the suction line) and then subtracting the saturation temperature (found
from the pressure-temperature chart using suction pressure). Use the
Dew Point pressure for blends.

Bubble Point - The pressure at which a blend starts to boil. Listed in
the pressure-temperature chart.

Dew Point - The pressure at which a blend nishes boiling. Listed in
the pressure-temperature chart.

L-2086

37

NOTES

NOTES

DOMETIC MARINE DIVISION
2000 N. Andrews Ave. Pompano Beach, FL 33069 USA
Tel [phone]
Fax [phone]
Mail

[e-mail]

24/7 TECH SUPPORT FOR UNITED STATES AND CANADA
8:00 AM to 5:00 PM Eastern Time: 800-542-2477
After hours and weekends: 888-440-4494

INTERNATIONAL SALES AND SERVICES
Europe and the Middle East: [phone]
For all other areas visit our website to find your nearest distributor.

dometic.com

L-0384 | 07/10/17