Dometic Kohler 7APU Instruction Manual

Heavy Duty Truck
Auxiliary Self-Contained
Heating & Air Conditioning System
Models:
7APU
TP-6512 2/07a
Operation and
Installation
by:

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L-2347K
Table of Contents
Self-Contained HVAC System for Truck
Sleepers • Introduction 4
Notice ................................................................................. 4
Drawings and Diagrams ..................................................... 4
Air Conditioning Basics ....................................................... 4
The Effect of Outside Air Temperature ................................ 4
Self-Contained System Components ................................. 4
Subsystems ........................................................................ 5
System Controls ................................................................. 5
Condensate Drain .............................................................. 5
Self-Contained HVAC System for Truck
Sleepers • Installation 6
Before You Start 6
Required Additional Parts ................................................... 6
Required Tools .................................................................... 6
Choosing The Correct Place
For Your Unit 6
Mounting The Unit .............................................................. 6
Wiring The Unit ................................................................... 7
Ducting The Supply Air ....................................................... 7
Attaching The Drain Hose .................................................. 8
Installing the Return Air Grill ............................................... 8
Self-Contained HVAC System for Truck
Sleepers • Operation 9
Starting Up Your New System 9
The SMXir Keypad/Display ................................................. 9
The SMXir Remote Control .............................................. 10
SMXir Basic Operation 11
Power On .......................................................................... 11
System Off ........................................................................ 11
Selecting Setpoint ............................................................ 11
Displaying Temperature .................................................... 11
Cool Mode ........................................................................ 11
Heat Mode ........................................................................ 11
Automatic Changeover ..................................................... 11
Manual Fan Speed Control ............................................... 11
Automatic Fan Speed Control ........................................... 11
Adjusting Brightness ......................................................... 11
Using The Humidity Control Routine ................................ 11
Anti-Ice Routine ................................................................ 12
Programming the SMXir System 12
Factory Memory Reset ..................................................... 12
Fahrenheit/Celsius Display ............................................... 12
Compressor Differential .................................................... 12
Fan Response Differential ................................................ 13
Low Fan Speed Adjustment ............................................. 13
High Fan Speed Adjustment ............................................. 13
Fan Mode ......................................................................... 14
AC Line Voltage Calibration .............................................. 14
Temperature Calibration ................................................... 14
Humidity Control Program 14
Programming The Time Period ......................................... 15
Programming The Dehumidification Time ......................... 15
Recommended Humidity Control Settings ........................ 15
Fault Shutdowns and Error Messages 15
Fault Codes ...................................................................... 15
Low Voltage Shutdown ..................................................... 15
Software Error .................................................................. 15
Determining Your Software Version Number ..................... 15
Quick SMXir Troubleshooting Guide ................................. 16
Troubleshooting 16
System Maintenance 17
Owner’s Limited Warranty 18
Description of Figures 20
Revised: 6-22-06

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L-2347K Introduction
Warning
This manual contains essential information concerning
the safe and proper installation and operation of your air
conditioning system. Read and follow all safety instruc-
tions in the manual and on the unit to help reduce the
risk of accident or injury or death. If there are any
statements or procedures that you do not understand,
contact your dealer.
Notice
US federal law prohibits the intentional release of refrigerant
gases into the environment, including the R-22, R134a, and
R417a refrigerant used in some air conditioning systems.
Special care must be taken when installing, charging, and
servicing this equipment to prevent any loss of refrigerant.
Only EPA certified technicians with the proper equipment
should perform service on the refrigerant circuit.
Drawings and Diagrams
The figures that are referenced throughout can be found at
the back of this manual. In addition, this equipment may be
shipped with specific installation sheets or wiring diagrams
that may supercede the information located herein.
Air Conditioning Basics
The basic principle of an air conditioner is the movement of
heat. In a direct expansion (DX) air-cooled air conditioner,
heat is transferred from the inside air to the refrigerant gas in
the evaporator coil. The refrigerant then is pumped by the
compressor to the condenser coil where the heat is released
to the outside air.
The heat exchange process relies on the movement of both
inside air through the evaporator coil and outside air through
the condenser coil. If airflow in either coil is compromised,
the efficiency of the system will drop. Continued usage with a
partially blocked air system will eventually damage the unit.
Severe airflow blockage will cause the unit to over-heat,
activate the unit’s safety devices, and shut the unit off.
Part of the cooling process, in addition to lowering tempera-
ture, is the removal of moisture from the air. This lowers the
humidity, which makes the area feel more comfortable and
helps keep the compartment dry.
The Effect of Outside Air Temperature
The performance of the air conditioner is dependent on both
outside and inside air temperatures. The unit is designed for
full capacity at 95°F (35°C) outside temperature. If the
temperature rises above this, the performance of the unit will
drop. However, the unit should still provide some cooling
even in temperatures as high as 125°F (52°C).
Heat is provided by an electric heat element and heat output
is not affected by outside temperature.
These systems are designed to cool or heat most common
sleepers, but may have limitations due to sleeper size, insula-
tion, the amount of glass, and the climate where the unit is
operated. Some tips to help maintain desired temperature are:
• Park in a shaded area when trying to cool.
• Cover windows with shades or towels to block direct
sunlight and limit heat transfer through the glass.
• Keep windows and doors closed.
• Close curtain between sleeper and cab.
• Reduce use of heat-producing appliances.
• When heating, park in a location that blocks prevailing
wind.
• When using shore power, make sure that the power cord
is the correct gauge for the amperage requirements of the
unit. If the power cord is too long and/or too small of a wire
(gauge), there can be a voltage drop at the unit, which will
affect performance, could cause damage, and may also
be a fire hazard. Power cord should be minumum 12
gauge wire.
Note - Moisture:
Dometic will not be held responsible for damage caused by
condensation of moisture on surfaces within the compart-
ment. Humid outside air contains water vapor, which, when
the outside air enters a cooled space, can condense on cool
surfaces such as windows, walls, or metal objects. Normal
operation of the air conditioner removes moisture from the
air, and keeping openings to the outside closed should
reduce secondary condensation.
Self-Contained System Components
Self-contained units have all major mechanical compo-
nents of an air conditioning system mounted on one chassis,
including the compressor, air-cooled condenser, evaporator
coil, blower, electrical box and related parts.
The self-contained unit is normally mounted in the compart-
ment. Inside air is pulled into the unit, where it is cooled or
heated, then discharged through ducting to a grill usually
located on a wall 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.
Self-Contained HVAC System for Truck Sleepers • Introduction

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L-2347K Introduction
Subsystems
Self-contained units require subsystems that are purchased
separately because of the many variations and options
available. These subsystems include the air distribution
system and the system control.
Air Distribution System
Compartment air is drawn into the self-contained unit
through a return air grill, it is cooled or warmed and blown
back into the compartment through a ducting system. The air
should be discharged high in the compartment and away
from the return air grill to ensure good circulation. Good air
distribution throughout the space is the key to comfort. An air
filter is located on the cooling unit or on the return air grill,
and must be cleaned regularly.
System Controls
SMX controls are advanced microprocessor systems that
provide a more comfortable environment and better system
protection than mechanical controls. In addition, over 20
programmable functions allow the user to customize the
system to suit the specific needs of their environment.
The SMXir System consists of the following components:
• Power/Logic (P/L) board - Monitors and controls all
functions of the air conditioning unit.
• Keypad/Display - A 10-button user interface with a digital
readout and LED indicators.
• Temperature-Sensing Element - Air temperature is
monitored 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 CXP connecting cable.
Condensate Drain
When the air conditioner is running, moisture is removed
from the air by the evaporator coil. This condensation is then
caught in a drain pan and must be drained off. In humid
climates the system can produce a large amount of conden-
sate water that could cause significant damage if the drain
system doesn’t work properly.
Warning
The drain should have a hose attached, and should
have a trap to create a water seal to prevent hazardous
or deadly gasses from entering!

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L-2347K Installation
Before You Start
1. Read installation and operating instructions carefully
before attempting to install and operate your air condition-
ing unit.
2. The manufacturer will not be liable for any damages,
injury, or death incurred due to failure to follow the
instructions.
3. Installations must always comply with the National
Electrical Code, and any state/local codes or regulations.
4. Only a qualified service technician must service this unit.
Any attempt to service the unit otherwise may void the
warranty.
5. Make sure that you have the required parts and tools to
complete the job, as this will help keep the installation
time to a minimum.
Warning
• Improper installation could damage equipment,
endanger life, cause serious injury, or property
damage.
• If you have any doubts that you cannot complete this
installation safely and as the directions state, find a
qualified technician to do it for you.
• Make sure that power is turned off at the source
before making any connections. Failure to do so could
cause injury or death.
Required Additional Parts
If you have received only the unit, and not the complete kit,
you will need to supply some additional parts for installation,
such as ductwork, grill(s), drain fitting, ½" X ½" wire mesh,
½" thick weather stripping, two 5½" hose clamps, one 1-1/8"
hose clamp, wiring, ¼" nuts and bolts, and 5/8" dia. drain
hose. The duct should be 5" diameter minimum. The two
large hose clamps can be used to secure the duct to the unit
and the grill to the duct. The drain fitting should be 3/8" MPT
to a 5/8" hose barb. The wire mesh will be used to put over
the holes that will be cut through the sleeper floor to assure
that small animals and other uninvited guests do not get into
the sleeper. Use the weather stripping to seal the area
between the AC unit and the floor of the sleeper. The wiring
sizes are noted in the SPECIFICATIONS section.
Warning
The seal between the unit and the floor is extremely
important. This seal is intended to prevent deadly
gasses from entering the living space!
Self-Contained HVAC System for Truck Sleepers • Installation
Required Tools
Tools that will aid in installation: drill and bits, 1-5/8" hole saw,
reciprocating saw with metal blades, Phillips and straight
blade screwdrivers, measuring tape, and Teflon tape or
equivalent.
Choosing The Correct Place
For Your Unit
The self-contained unit is easier to install than the remote
system, but it will take up more room under the bunk. A
remote system consists of two major components, the
condenser and the evaporator, while the self-containted unit
stands alone. The remote condenser is installed outside the
cab; the remote evaporator is installed inside the sleeper.
Generally speaking, the self-contained unit is installed with
the long dimension lengthways of the sleeper. This would put
the evaporator intake close to the bunk bulkhead. The
evaporator intake must be have a minimum open area equal
to the size of the coil face. For example, a coil that is 10" x
9½" would require 95 in
2
of open return to the unit. The
evaporator discharge can then be ducted to wherever best
suits the truck arrangement.
Mounting The Unit
Installing the Self-Contained Unit
Decide where you are going to install the unit. Using the
template provided, mark off the required holes (condenser
inlet and outlet, mounting holes, and drain hole), and check
for interference between the holes and the structural
members that are under the sleeper floor. After you have
checked, cut the holes in the floor of the sleeper. Use the
wire mesh to cover each hole so that small animals cannot
get in. Take the weather stripping, and make a frame around
the holes on the unit. Install the MPT drain fitting into the
drain hole using the Teflon tape. Line the unit up over the
holes, and set squarely onto the floor.
NOTE: Take care not to crush or break the drain fitting while
moving the unit around. Use the four bolts, washer and nuts
to secure the unit to the floor.
NOTE: The manufacturer is not responsible for mounting, nor
is responsible for failure of such mounting and subsequent
unit damage. The unit will need to be positioned so that
electrical and refrigerant connections can be accessed, and
so that cleaning of the condenser coil may be performed.
The unit should be securely fastened to the mounting frame
with ¼" bolts and lock nuts.

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L-2347K Installation
Controls
Two types of controls are used with these self-contained
units. Model ASCF7 has a built-in mechanical control. All
other models use the SMXir digital keypad/display which is
sold separately.
If you have model ASCF7, then read the below section
“Mechanical Controls” and ignore all information on the
SMXir control. Review the sections “Troubleshooting” and
“System Maintenance” for future reference.
If your system uses the SMXir digital keypad/display, then
you may skip the “Mechanical Controls” section and start
with the section “SMXir Controls”, reading through to the end
of this manual.
Mechanical Controls
The mechanical control on model ASCF7 is built-in and
requires no additional installation. To operate the mechanical
control, follow these instructions:
1. Turn power on to the system.
2. Set the thermostat to the coldest setting by rotating it fully
clockwise.
3. Set the FAN/COOL selector switch to HI COOL.
4. Close all doors and windows to your sleeper compart-
ment.
5. Once the temperature reaches a comfortable level, rotate
the thermostat slowly counterclockwise, stopping at the
point where the unit cycles off. That is now the setpoint.
The fan will run faster on HI COOL and slower on LO COOL
as the system cycles on and off in the cooling mode. Or, if
you just want the fan only, then choose the LO FAN or HI
FAN settings. Model ASCF7 with the mechanical control
does not supply heat.
SMXir Controls
The SMXir digital keypad/display may be mounted in any
convenient location, on a bulkhead or in a cabinet or closet,
for instance. Choose a location that is easy to reach, but not
in the way of daily routines. Make sure that the mounting
location is within the display cable (CXP) length of the A/C
unit. Route the CXP cable prior to mounting SMXir control.
Use the enclosed instructions for mounting the SMXir. Drill a
hole for the CXP cable to feed through. Mount the display
backing plate centered over that hole. Run the cable through
the hole and plug it into the display. Then snap the display
onto the backing plate, being careful not to crimp the cable.
The other end of the CXP should be plugged into the SMX
circuit board/elec box socket marked “DISPLAY”. The other
cable that is plugged into the SMX circuit board/elec box is
the TSEP (temperature sensing element). That cable is
mounted on the unit in front of the evaporator coil in the
return air stream and is plugged into the socket marked
“TEMP”. CXP cables are available in a variety of lengths,
please contact your dealer if need be. Although the CXP
looks like a standard telephone cable, it is not; phone cables
will not work as a display cable. Access the elec box by
removing the panel on the end of the unit, above the cable
feed-thru holes.
Warning
Make sure all power is off before opening any
electrical box.
Warning
The SMX interconnect (C XP) and temperature sensor
cables (TSEP) transmit low voltage DC signals, and
outside interference can affect their operation. Do not
route these cables beside A/C power cables, high
voltage wiring, or antenna wires. Keep the cable runs as
short as possible to reduce the chance of interference.
Wiring The Unit
Warning
Care must always be exercised when dealing with
electricity. Wiring should be done only by a qualified
technician. Contact an electrician if you have any
questions.
Refer to the wiring diagrams in the back of this manual or the
diagram that is located inside the electrical panel of the unit.
The unit should be wired according to power requirements
given on the data plate and per NEC recommendations. The
unit must alwasy be grounded. Always refer to NEC or state/
local codes for further wiring recommendations.
Ducting The Supply Air
The supply air grill should be mounted in a place that will
allow for the best air distribution, preferably up high. Locate
the best place to mount the grill and verify that you have
enough duct to cover the length between the unit and the
grill. Cut out for the grill, and mount securely. Use the large
hose clamps to secure the duct to the unit and to the back of
the grill. Air discharged through low-mounted grills should be
directed upward by tuning the louvers 45° up.

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L-2347K Installation
Attaching The Drain Hose
Climb under the sleeper with the length of 5/8" diameter
hose and the small hose clamp. Secure the hose to the hose
barb with the clamp. Secure the hose to something under the
sleeper that is fixed. Fashion the hose such that is forms a
trap, such as a plumber’s running trap. The trap will help
keep fumes and bugs out by providing a water seal.
Installing the Return Air Grill
Install the return air grill so that the path between the grill
and the coil face of the unit is open and unrestricted. The
path should not be any smaller in square inch area than the
size of the coil face. Place the grill so that it will not be
covered up by cargo, sheets, boxes, etc.

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L-2347K Operation
Self-Contained HVAC System for Truck Sleepers • Operation
Starting Up Your New System
SMXir Quick Start
Use the COOL or HEAT button to start desired function.
Push the SET button to put the switch into temperature
programming mode. Use the UP and DOWN buttons to
adjust the temperature up or down. Use the FAN button to
put the fan on automatic mode, or use the FAN SPEED
buttons to adjust the fan manually.
The SMXir Keypad/Display
The SMX keypad/displays are arranged for logical operation.
See next page for keypad/display diagrams.
1. Data Display
Large LED readout that provides indication of current
setpoint, temperatures, programmed values and error
messages.
2. Cooling Indicator
Lights when compressor is running in cooling mode.
3. Heating Indicator
Lights when system is running in heating mode. This unit
is supplied with electric heat only.
5. SET Key
Press the SET key to display your currently selected
setpoint (the temperature you wish to maintain in the
room). The SET key also is used to dim the data display
readout.
6. UP-DOWN Keys
Press UP or DOWN to raise or lower the setpoint. Press
and hold keys for large changes. Note: if inside tempera-
ture is displayed, touching the UP or DOWN key will
cause the setpoint to be displayed.
7. TEMP Key
Press once to display inside temperature. Press TEMP
twice, and the display will alternate between inside
temperature and setpoint. Press again to return to inside
temperature only.
Hint
You can display temperature in degrees Fahrenheit or
Celsius.
8. OFF Key
Turns system off. Note that the data display remains on.
You can continue to adjust setpoint, display temperature
readings and activate the manual fan to circulate air
while the system is in the OFF mode.
9. Cool Mode Indicator
Lights when you press the COOL key to select the
cooling mode.
10. Heat Mode Indicator
Lights when you press the HEAT key to select the
heating mode.
11. COOL Key
Turns the system on in the cooling mode.
12. HEAT Key
Turns the system on in the heating mode.
Hint
Press both HEAT and COOL at the same time, and the
system will automatically switch between cooling and heating
mode. When in the automatic switchover mode, both the
COOL and HEAT indicators are lit.
13. Manual Fan Indicator
Lights when fan is running in manual mode.
14. SLOW-FAST Keys
Control fan speed when the fan is in the manual mode.
Pressing SLOW or FAST key when in automatic fan
mode will change the system into manual mode.
15. FAN Key
Selects manual or automatic fan control mode. Press
once to select manual control. Press FAN again to select
automatic fan speed control. In this mode, the fan speed
is controlled by the microprocessor as a function of the
difference between setpoint and inside temperature.
16. Fan Speed Indicators
Row of five small LEDs below FAN key. Indicate the
current fan speed.
17. Inside Temperature Indicator (SMXir Display Only)
When illuminated, inside temperature is displayed.
When light is off, setpoint is displayed.
18. IR Receiver (SMXir Display Only)
Infrared remote receiver
19. Dehumid Key (Remote Control Only)
Changes system into the Humidity Control program.
20. Auto Switchover Key (Remote Control Only)
Places the system into automatic changeover mode, so
it will switch from cooling to heating as needed.

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L-2347K Operation
Definitions
LED - Light Emitting Diode. An indicator light is used to
denote mode or operating status.
Setpoint - The selected temperature you want to maintain in
the area being heated or cooled.
The SMXir Remote Control
The optional SMXir remote control keypad has the familiar
layout of the 10-button SMX keypad, and performs most of
the same functions. The remote cannot be used to program
settings. Programming must be done at the keypad/display.
In addition to the standard keys, the SMXir remote also has
two quick-hit buttons that allow easy access to the humidity
control program and the automatic changeover mode.
The remote control has three buttons that are not used on
this system: Aux Heat, Aux Heat Auto Switchover, and Aux 1.
The SMXir remote control must be pointed at the SMXir
keypad/display, which has the IR remote receiver. The
remote will not work if the SMXir keypad/display has the
optional full coverage door and the door is closed.
The SMXir remote control is optional and must be ordered
separately.
SMXir Remote Control
SMXir Keypad/Display
(see previous page for details)

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L-2347K Operation
SMXir Basic Operation
Power On
When AC power is applied to the system at the circuit
breaker, the SMX microprocessor performs a self-check and
retrieves from permanent memory the last operating configu-
ration. This process takes about four seconds, after which
the system will begin operating just as it had been when
power was last turned off.
Note: These systems have a 2-minute compressor restart
delay to allow the system refrigerant pressures to equalize
before starting. This delay begins when the compressor
shuts down for any reason. This delay is increased by the
Compressor Time Delay function so that vehicles with
multiple units can be set to prevent all units from turning on
at the same time if power is lost and restored.
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 configuration in permanent memory every time you
make changes. (The new operation mode must be in affect
for 30 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 opera-
tion using the same settings as before.
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 room temperature, press the TEMP key. Press
TEMP twice for an alternating display of inside temperature
and setpoint. Press again to return to inside temperature
only.
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 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 electric heat element is energized.
When the heat element cycles off, the Heating Indicator
goes off, but the Heat Mode Indicator stays on.
Automatic Changeover
Press the COOL and HEAT keys simultaneously for AUTO-
MATIC CHANGEOVER between COOL and HEAT Modes.
Both mode indicators will light, to show that the system is in
the 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 (or heater) is running to show when the
system is running in the cooling or heating mode.
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.
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 room temperature
deviates from the setpoint. As setpoint is approached, the
fan speed automatically slows. Once setpoint is reached, the
compressor 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.
Using The Humidity Control Routine
When engaged, the SMX humidity control routine automati-
cally turns the air conditioning system on at timed intervals to
remove moisture from the air. The system is programmed at
the factory for average values. To change the factory
settings, see “Humidity Control Program”.

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L-2347K Operation
To start the dehumidification program:
• Press OFF.
• Press COOL, HEAT and FAN keys simultaneously.
For the SMXir Remote Control only - Press the
Dehumid key to enter dehumidification mode.
• The data display will flash HU, indicating that the program
is active.
• To halt the dehumidification program, press any key. The
HU message will stop flashing.
Safety Note
Whenever the SMX system is in the dehumidification mode,
all of the system safeguard controls remain active. If the
pressure switches open 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 dehumidification mode when power is restored.
Anti-Ice Routine
The SMX control has an anti-ice routine that 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 when the inside temperature
drops below a certain temperature.
The compressor will shut off for 15 seconds (in a 10-minute
cycle period) for every degree (F) below 64°F (18°C). For
example, if the inside temperature is 62°F, the compressor
will shut off for 30 seconds, plus the 2 minute restart delay,
every 10 minutes.
Programming the SMXir System
The following programming changes are to be made by a
trained technician or with the aid of a factory tech.
SMX control systems are programmed at the factory for
optimal values.
All programming steps are entered by pressing the OFF key,
followed by the SET key, then simultaneously depressing the
two or three keys noted in the table below. Successful entry
into a programming mode is indicated by the presence of a
decimal point to the right of the two displayed characters. To
raise or lower a value, touch the UP or DOWN keys. To exit
the programming mode, touch the OFF key. (The SMXir
Remote Control cannot be used to program the system.)
Factory Memory Reset
You can use the memory-reset sequence to restore all
programmed functions to the factory default settings.
To restore programmed functions to factory setting:
• Press OFF, SET and FAN simultaneously.
• Press SET.
• After a delay, the memory will be reset from stored values.
After another delay, the display will come back on nor-
mally.
Fahrenheit/Celsius Display
(Factory Default: Fahrenheit)
You can choose to view temperature in degrees Fahrenheit
or Celsius.
To select Fahrenheit or Celsius:
• Enter the programming mode: Press OFF, Press SET
• Press DOWN, TEMP and UP simultaneously.
• Use the UP or DOWN key to select F for Fahrenheit or C
for Celsius.
• Press OFF to exit programming mode.
Note
If you switch from Fahrenheit to Celsius for temperature
displays, the compressor restart differential will also operate
on degrees Celsius. Thus, the factory-set compressor restart
differential will be 1.5°C, which is too wide. To correct this,
reset the differential value from 12 to 6. This will provide a
differential of 0.75°C, or about 1.4°F.
This will also affect the Fan Response Differential, which is
factory set at a value of 4, or 0.5°F. When changing from
Fahrenheit to Celsius, you should reset the Fan Response
Differential from 4 to 2. This will provide a fan differential of
0.25°C, or about 0.5°F.
Compressor Differential
(Factory Default: 12 = 1.5°)
The compressor differential is the temperature change needed
for the compressor to cycle on and off. The factory setting of
1.5°F should be adequate for most applications. Differential
selections are available in increments of 1/8°. Thus, to select
one degree, you should choose 8 (for 8-eighths).
To program the compressor differential:
• Enter the programming mode: Press OFF, Press SET
• Press SLOW and FAN simultaneously. The restart
differential will be displayed.
• Use the UP or DOWN key to change the setting.
• Press OFF to exit the programming mode.
Hint
Be careful not to set your compressor restart differential too
low, since it will cause the compressor to start and stop quite
often. This will place an undue load on your electrical system
and wear on the compressor.

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L-2347K Operation
Fan Response Differential
(Factory Default: 4 = 0.5°)
When the fan is in the automatic mode, its speed is gov-
erned by how far the room temperature differs from the
setpoint. The fan runs faster when the difference is great. As
the room cools or warms, the temperature approaches
setpoint, and the fan slows down automatically. The amount
of temperature rise in the room above setpoint needed to
cause the fan to increase in speed one step is called “fan
speed differential”. It can be adjusted from 1/4° to 4°, in 1/8°
increments.
The fan speed range is divided by the SMX microprocessor
in five equal increments. If the fan response differential is set
at 1/2°, the fan speed will change 20% for each 1/2° of
temperature deviation from setpoint. Lowering the fan speed
differential will cause the fan to increase speed quickly as
temperature changes. Raising the fan speed differential will
result in slower fan speed changes for a given temperature
change. The factory setting of 1/2° Fahrenheit is good for
most applications, but you may wish to try a slightly higher
setting in your salon and a lower setting in your sleeper
compartment.
To adjust fan response differential:
• Enter the programming mode: Press OFF, Press SET
• Press COOL and SLOW. The differential will be displayed
in increments of 1/8°.
• Use the UP or DOWN key to raise or lower this value.
• Press OFF to exit the programming mode.
Low Fan Speed Adjustment
(Factory Default: 32)
You can adjust the lowest fan speed to suit individual
preferences. For instance, you may wish to decrease the low
fan speed setting in your sleeper compartment to minimize
fan noise.
To adjust low fan speed:
• Enter the programming mode: Press OFF, Press SET
• Press DOWN and SET simultaneously. The current low
speed reference number will be displayed (factory set
at 32).
• Press UP or DOWN to raise or lower speed reference
number.
• Press OFF to exit the programming mode.
Hint
For most efficient operation of your system, you should
normally keep the low fan speed at the highest possible
setting consistent with a comfortable noise level. Running the
fan speed too slow can damage the compressor.
High Fan Speed Adjustment
(Factory Default: 60)
A blower will often reach its highest speed at a voltage lower
than full line voltage. For example, at a line voltage of 120V,
the blower might reach its fastest speed at 110V. At higher
voltages, the bower speed will not increase significantly.
The SMX High Fan Speed Adjustment allows you to set the
maximum high-speed voltage to the threshold of the blower
high-speed response. Because SMX breaks up the fan
Programmable Function Keystroke Combination Factory Setting Range
Factory Memory Reset OFF & SET & FAN, then SET
Compressor Time Delay DOWN & SET & UP 0 0 to 70 sec.
Fahrenheit/Celsius DOWN & TEMP & UP F F or C
Compressor Differential SLOW & FAN 12 4 to 24
COOL & SLOW
(SLOW & FAN & FAST Before 8/98)
Low Fan Speed DOWN & SET 32 30 to 56
High Fan Speed SET & SLOW 60 41 to 90
Fan Mode (Cont. or Int.) DOWN & FAN & UP C C or I
AC Line Voltage Calibration DOWN & UP - ± 1%
Temperature Calibration SET & UP - ± 1%
HU Precirculation TEMP & DOWN 10 Min. 10 Min.
HU Dehumidification TEMP & SET 30 Min. See “Humidity
HU Time Period TEMP & UP 12 Hrs. Control Program”
EPROM Version COOL & DOWN
EPROM Revision COOL & DOWN, then UP
Fan Response Differential
See table below before reset
4 2 to 8

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L-2347K Operation
speed voltage steps into 5 equal parts (between the low-
speed and high-speed adjustments), accurately setting the
high-speed adjustment can help ensure that each fan speed
step results in a noticeable change of fan speed.
To adjust the high fan speed:
• Enter the programming mode: Press OFF, Press SET
• Press SET and SLOW simultaneously. The current high-
speed reference number will be displayed (factory default
is 60).
• While listening to the fan noise level, use the UP key to
raise the displayed value past the point that you can hear
an increase in the fan noise level.
• Press the DOWN key to lower the voltage until you hear a
drop in fan speed, then raise that number up by 2 or 3 to
ensure that it is set at the highest speed.
• Press OFF to exit the programming mode.
Fan Mode
(Factory Default: Continuous)
You can select continuous fan operation or instruct the fan to
cycle on and off with the system compressor.
To select continuous or intermittent fan:
• Enter the programming mode: Press OFF, Press SET
• Press DOWN, FAN and UP simultaneously.
• Use the UP or DOWN key to select C (continuous) or
I (intermittent).
• Press OFF to exit the programming mode.
Hint
If you select intermittent fan operation, you should relocate
the thermistor from the return air duct to an inside wall to
best sense room temperature. Check with your dealer or call
the Dometic Applications Department for more information.
AC Line Voltage Calibration
The SMX control assembly has a built-in voltmeter that
senses AC line voltage. The microprocessor automatically
responds to sustained low-voltage conditions by shutting
down the air conditioning system to prevent compressor
damage.
At installation, the SMX voltmeter is calibrated to line voltage
within +/- 1%.
To check or recalibrate AC line voltage:
• Enter the programming mode: Press OFF, Press SET
• Press DOWN and UP simultaneously. Line voltage will be
displayed in 2 digits. On 115V systems, 95V appears as
95, 100V as 00, and 120V as 20. For 230V systems the
reading shows 1/2 of line voltage, therefore, 190V will
appear as 95, 200V as 00, and 230V as 15.
• To check accuracy or to calibrate, turn off all on-board AC
loads and measure the line voltage with an accurate
voltmeter.
• If the SMX displayed voltage is not correct, press the UP
or DOWN key to enter the correct value.
• Press OFF to exit the programming mode.
Temperature Calibration
Typically, the temperature sensor is within 1 or 2 degrees of
actual room temperature. If off by more, it can be calibrated
to read actual temperature.
To calibrate the thermistor:
• Enter the programming mode: Press OFF, Press SET
• Press SET and UP simultaneously. The sensed tempera-
ture will be displayed.
• Place an accurate thermometer beside the thermistor you
are using and compare the temperatures.
• Use the UP or DOWN key to adjust the displayed tem-
perature to the correct value.
• Press OFF to exit the programming mode.
Humidity Control Program
The SMX dehumidification program automatically runs the
air conditioning system for a programmed time period to help
control humidity in the vehicle. The dehumidification program
works in 3 stages:
1. The fan comes on at high speed to circulate air for 10
minutes.
2. The fan then drops to low speed, and the compressor
cycles on in the cooling mode to dehumidify.
3. After the dehumidification cycle, the system turns off. The
process repeats according to the programmed time
period.
The compressor time delay setting will affect when the
dehumidification cycle starts. Every 1-second of compressor
delay equals a 6-minute advance into the dehumidification
cycle. This can cause the dehumidification cycle to skip the
first running and wait until the next time period.
The factory default settings are:
Overall time period ......................... 12 hours
Precirculation cycle ........................ 10 min.
Dehumidification cycle ................... 30 min.
The factory settings are adequate for most moderate
climates and boats. For humid climates, you may wish to
shorten the overall time period and extend the dehumidifica-
tion time. In dry climates, you can select longer intervals
between cycles and a shorter dehumidification time.

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L-2347K Operation
Programming The Time Period
(Factory Default: 12 hours)
The time period determines how often the system performs
the dehumidification process. You can select intervals of 2, 4,
6, 8, 10, 12, 14 or 16 hours. Chose a shorter time period in
climates with high humidity.
To select time period:
• Enter the programming mode: Press OFF, Press SET
• Press TEMP and UP simultaneously. The display will
show the overall time period in hours.
• Use the UP or DOWN key to select the desired time
period.
• Press OFF to exit the programming mode.
Programming The Dehumidification Time
(Factory Default: 30 minutes)
The dehumidification time determines how long the com-
pressor runs in the dehumidification mode. You can select
10, 20, 30, 40, 50 or 60 minutes. Select a longer dehumidifi-
cation time in humid climates.
To select dehumidification time:
• Enter the programming mode: Press OFF, Press SET
• Press TEMP and SET simultaneously. The display will
show the time period in minutes.
• Use the UP or DOWN key to select the desired time
period.
• Press OFF to exit the programming mode.
Recommended Humidity Control Settings
Fault Shutdowns and Error Messages
The SMX control contains built-in safeguards designed to
protect your air conditioning system from damaging condi-
tions. These are described below.
Fault Codes
If an operational failure occurs, the display will flash one of
the following fault code messages. Fault code displays are
cancelled by pressing OFF.
Low Voltage Shutdown
The low-voltage protection feature is always active. If AC line
voltage drops and remains below 100 volts (200 volts for a
230V system) for more than three minutes, the SMX shuts
down the entire system. The display will flash LO-AC (for low
AC). This is a sustained shutdown, and the system will not
resume operation even if the line voltage rises to normal
levels. To reset, press the OFF key.
Hint
For the low voltage shutdown function to work properly, the
SMX internal voltmeter should be calibrated. This is normally
accomplished at installation. To check or recalibrate line
voltage, see “Programming Summary Table”.
Software Error
Whenever power is applied to the SMX, the microprocessor
goes through an automatic self-check and software loading
process. If all is well, the SMX loads the most recent operat-
ing configuration from its internal memory, and turns on
normally. If a program fault is found during the self-check, the
error message PE will be displayed.
Likewise, the self-diagnostic routine runs continuously
whenever the SMX system is on. If a system fault is de-
tected, the system shuts down, and the PE error message
appears.
If this message occurs, contact your nearest dealer, or call
the Factory Service Department in Richmond, Virginia (804-
746-1313) for assistance.
Determining Your Software
Version Number
When you call your dealer or the factory for service assis-
tance, it’s helpful to know the Software Version Number for
your SMX system.
Press OFF then SET, then COOL & DOWN simultaneously.
The display will show the version number. Then press UP
and the display will show the revision level.
Outside Relative Time Dehumid.
Temperature Humidity Period Time
Below 80° F 75-85% 12 hrs 10 min
(27°C) Above 85% 8 hrs 20 min
80° - 90° F 75-85% 10 hrs 30 min
(27° - 32°C) Above 85% 6 hrs 40 min
Above 90° F 75-85% 8 hrs 40 min
(32°C) Above 85% 6 hrs 60 min

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L-2347K Operation
Quick SMXir Troubleshooting Guide
Problem: SMXir Display Not On
Possible Solution:
1. Turn circuit breaker on
2. Check CXP cable and connections
3. Replace keypad/display
4. Replace Power/Logic board
Problem: Erratic Temperature Display
Possible Solution:
1. Perform a Factory Memory Reset
2. Check temperature sensor, cable and connection
3. Ensure the temperature sensor is installed properly
4. Calibrate temperature
5. Replace Power/Logic board
Problem: Erratic system operation
Possible Solution:
1. Perform a Factory Memory Reset
2. Check CXP cable and connections
3. Check temperature sensor, cable and connection
4. Replace keypad/display
5. Replace Power/Logic board
Warning
The Power/Logic board operates at 115VAC or 230VAC.
Make sure the power is off before removing the cover of
the Power/Logic box.
Contact an authorized servicing dealer if the problem
continues, or for replacement parts.
Troubleshooting
Symptom: Unit does not operate at all
Suggested Solutions:
1. Check the switch to make sure it is set to the desired
function.
2. Check the temp. setpoint to make sure it is sufficient for
the unit to run.
3. Make sure that the generator is running, or shore power is
connected.
4. Ensure the unit’s circuit breaker is ON, and not tripped.
Symptom: Unit doesn’t make cold air
Suggested Solutions:
1. Check the temp. setpoint to make sure it is sufficient for
the unit to cool.
2. Check the evaporator air filter, clean as needed.
3. Make sure switch is set to COOL.
4. Make sure evaporator blower is running by checking for
airflow from the grill.
5. Make sure that the condenser blower is running by
checking for airflow under the sleeper.
6. Check the condenser coil while under the sleeper. If it is
dirty, clean it.
7. Check the evaporator coil to make sure it is not frozen up.
Sometimes, during cool outside weather, and a low fan
speed, the coil may ice up. Turn the temp. setpoint so that
the compressor cuts off, and turn the fan to maximum
speed. Allow unit to defrost, then resume cooling.
Symptom: Unit doesn’t make warm air
Suggested Solutions:
1. Make sure switch is set to HEAT.
2. Check the evaporator air filter, clean as needed.
3. Make sure evaporator blower is running by checking for
airflow from the grill.
4. Check the manual reset button on the front of the unit.
Reset by pushing with a pencil or other small device.
Symptom: Unit doesn’t cool or heat sufficiently
Suggested Solutions:
1. Change the setpoint of the thermostat as required.
2. Check evaporator air filter, clean as needed.
3. Check condenser coil, if it is dirty, then clean it.
4. Close curtains over windows and between the cab and
sleeper.
5. Call a service technician. Do not attempt internal repairs
yourself.

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L-2347K Operation
System Maintenance
System maintenance should be a regular program of
equipment upkeep that will keep your system running well for
years to come. There should be no need to change refriger-
ant or add refrigerant regularly unless there is a problem. If
refrigerant needs to be added, consult a service technician.
It is not suggested that internal repairs be tackled by
anyone except trained technicians.
Component Necessary Action
Compressor No maintenance is necessary.
Condenser Blower No maintenance is necessary.
Evaporator Blower No maintenance is necessary.
Heater No maintenance is necessary.
Evaporator Filter Remove, and wash with soapy water
or blow out with compressed air
monthly
Condenser Screen Clean debris from screen every
month during the cooling operating.
Condenser Coil Clean with water and soap once
yearly to remove oils and debris.
Drain Tubing Check for obstructions and position-
ing before the cooling season.
WARNING
Dometic Environmental Corporation (Dometic) manufacturers of Cruisair, Dometic
Auxiliary A/C, Dometic Refrigerators and Freezers, Eskimo Ice, Grunert, Marine
Air, and Sentry products, makes the following safety warnings concerning the
application, installation, use and care of its products. Although these warnings are
extensive, there may be specific hazards which may arise out of circumstances
which we have not outlined herein. Use this as a guide for developing an
awareness of potential hazards of all kinds. Such an awareness will be a key
factor in assuring your SAFETY and comfort.
ELECTRICITY - Many Dometic products operate on 115, 230 or 440 volt AC
power. Such voltages can be LETHAL; therefore, the chassis, cabinets, bases,
etc., on all components must be grounded together and connected to the vessel's
grounding system. Sparks can occur as switches, thermostats and relays open
and close in the normal operation of the equipment. Since this is the case,
ventilating blowers for the removal of hazardous fumes or vapors should be
operated at least 5 minutes before and during operation of any Dometic product or
group of Dometic products. All electrical connections must be covered and
protected so accidental contact cannot be made by persons using the equipment,
as such contact could be LETHAL.
ELECTROLYSIS - Electrical leakage of any component can cause electrolytic
deterioration (electrolysis) of thru-hull components which could result in leakage
serious enough to sink a vessel which could result in loss of life. All Dometic
components must be kept clean and dry and checked periodically for electrical
leakage. If any electrical leakage is detected, the component should be replaced
or the fault causing the leakage corrected before the component is put back into
service.
GAS - Dometic Air Conditioning and Refrigeration components utilize R-22
(Chlorodifluoromethane), R134a refrigerant (Tetrafluoroethane), R-407C (which
contains Diflouromethane [HFC-32], Pentafluoroethane [HFC125], and 1.1.1.2 -
Tetrafluoroethane [HFC134a]), R404A (R125/R143a/R134 [44%/52%/4%]), or
R417a, which are non-toxic, non-flammable gases; however, these gases contain
no oxygen and will not support life. Refrigerant gas tends to settle in the lowest
areas of the compartment. If you experience a leak, evacuate all personnel, and
ventilate area. Do not allow open flames in the area of leaks because refrigerant
gas, when burned, decomposes into other potentially LETHAL gases. Refrigerant
components operate at high pressure and no servicing should be attempted
without gloves, long-sleeved clothing and eye protection. Liquid refrigerant gas
can cause severe frost burns to the skin and eyes.
VENTILATION - To cool or heat air, Dometic Air Conditioning and Refrigeration
components are designed to move air through a heat exchanger by a blower or
propeller fan. This design necessarily produces a suction on one side of the air
handling component and a pressure on the other side. Air handling components
must be installed so that the suction-pressure action does not: (1) pressurize an
area to the extent that structural failure occurs which could cause harm to
occupants or bystanders, or (2) cause a suction or low pressure in an area where
hydrogen gas from batteries, raw fuel vapor from fuel tanks, carbon monoxide
from operating propulsion engines, power generators or heaters, methane gas
from sewage holding tanks, or any other dangerous gas or vapor could exist. If an
air handling unit is installed in such a manner that allows potentially lethal gases
or vapors to be discharged by the air handling unit into the living space, this could
result in loss of life.
Maximum protection against the introduction of dangerous gases or vapors into
living spaces can be obtained by providing living spaces which are sealed from all
other spaces by use of airtight bulkheads and decks, etc., and through the
introduction of clean air into the living space. Bear in mind that the advent of air
conditioning, whether it be for cooling or for heating, naturally leads to the practice
of closing a living space tightly. Never close all windows and doors unless
auxiliary ventilating systems, which introduce clean outside air into the living
space, are used. Always leave enough window and door openings to provide
adequate ventilation in the event potentially lethal gases or fumes should escape
from any source.
CONDENSATE - All cooling units produce water condensate when operating on
the cooling cycle. This water must be drained from the cooling unit overboard. If
condensate is allowed to drip on a wooden structure, rotting or decay and
structural failure may occur which could result in loss of life. If condensate is
allowed to drip on electrical components, deterioration of the electrical compo-
nents could result in hazardous conditions. When an air conditioning system is in
operation, condensate drains may be subjected to negative pressure. Always
locate condensate drains as far as possible from points where engine waste and
other dangerous gases are exhausted so no such dangerous gases can be drawn
into the condensate drains.
Warning
Never sleep in a closed area on a boat when any equipment, which functions as a
result of the combustion of a volatile fuel, is in operation (such as engines,
generators, power plants, or oil-fired heaters, etc.). At any time, the exhaust
system of such devices could fail, resulting in a build-up of LETHAL gases within
the closed area. Warning Revised: 6-5-06

18
L-2347K
Fig. 1 Unit Specifications
Fig. 2 Wiring Diagram for ASCDX14 (080359)
Fig. 3 Wiring Diagram for ASCDX10 (080343)
Fig. 4 Wiring Diagram for ASCEX7 (080356)
Fig. 5 Wiring Diagram for ASCF7 (080344)
Description of Figures

19
L-2347K
Fig. 1 Unit Specifications
Model Cooling Capacity Heating Height Width Length Weight Cooling Heating
Number (BTU/Hr) Capacity (KW) (in) (in) (in) (lbs) (amps) (amps)
ASCF7 7,000 N/A** 12.50 15.25 21.50 62.00 8.50 -
ASCEX7 7,000 1.50 11.94 17.75 24.00 71.00 8.90 13.40
ASCDX10 10,000 2.00 12.50 20.87 28.25 92.00 12.9019.10
ASCDX14 14,000 2.50 12.50 20.87 31.50 104.00 15.70 24.00
Full Load Amperage*
NOTES: The system is rated to provide full capacity at 95°F (35°C) outside temperature. Actual performance will be
affected by factors such as ambient temperature and humidity, insulation, direct sunlight and reflected heat.
*Full Load Amperage at 120VAC.
**Heat option not available for 7,000 BTU cool-only models. Other heat capacities are optional.

20
L-2347K
Fig. 2 Wiring Diagram for ASCDX14 (080359)