Dometic Duo-Therm 39325.502 Manual

1
USA
SERVICEOFFICE
TheDometicCorp.
509So.Poplar St.
LaGrange,IN46761
CANADA
DometicDist.
866LangsDr.
Cambridge,Ontario
CANADAN3H2N7
FormNo.3105532.018 8/94
©1994 TheDometic Corp.
LaGrange,IN 46761
INSTALLATION & OPERATING
INSTRUCTIONS
RECORD THIS INFORMATION FOR FUTURE REFERENCE
BEFORE INSTALLING THE UNIT:
ModelNumber
SerialNumber
DatePurchased
PlaceofPurchase
AVERTISSEMENT
Une mauvaise installation, de mauvais
réglages, modifications ou opérations
d’entretien peuvent endommager les
biens ou même blesser. Se reporter à
la notice. Pour obtenir de l’aide ou des
reseignements complémentaires,
consulter un installateur qualifié ou
une agence de service après-vente.
WARNING
Improperinstallation,adjustment,
alteration,serviceormaintenance
can cause injury or property dam-
age. Refer to this manual. For as-
sistanceoradditionalinformation
consultaqualifiedinstallerorser-
vice agency.
®
®
SELF-CONTAINED HEAT PUMP
FOR BASEMENT
PARK MODEL
ROTARY COMPRESSOR
SYSTEM MODELS
39325.502
THIS UNIT IS DESIGNED FOR OEM INSTALLATION
ALL INITIAL INSTALLATIONS MUST BE APPROVED BY THE SALES DEPT.
SYSTEM
MODELS
39325.502

2
INDEX
1. Specifications,GeneralInformation,Location ....................... 2
2. OutdoorSection .................................................................... 3
A. FreeArea ....................................................................... 3
B. Mounting ........................................................................ 3
C. ServiceAccess............................................................... 3
3. IndoorSection....................................................................... 3
A. Clearances ..................................................................... 3
B. InletAir ........................................................................... 3
C. OutletAir ........................................................................ 3
4. ElectricalWiring ....................................................................4
5. ThermostatMounting ............................................................5
6. ThermostatWiring ................................................................5
7. Ducts ....................................................................................7
8. Maintenance .........................................................................7
9. Servicing ...............................................................................7
10. Wiring Diagram .....................................................................8
1. SPECIFICATIONS, GENERAL INFORMATION & LOCATION
GENERAL INFORMATION
The Basement/Park Model heat pump was designed to
operate in a MILD GEOGRAPHICAL AREA for heating
where the heat loss is minimum. The 39325.502 will
operate down to an outside ambient temperature of 40
degrees.At40degrees,theoutdoorthermostatwillturnoff
the heat pump circuit and start up the coach's main
furnace. As long as the temperature remains below 40
degrees, the main furnace will heat your home.
As the outside temperature increases to 45 degrees, the
outdoorthermostatswitchesbackto the heat pumpcircuit.
The advantages of the 39325 Heat Pump Central Air
Conditioner are:
1. User friendly; only one unit for both heating and air
cooling.
2. Heatpumpheatingusesthecampsiteelectricalhookup
and you save on trips to refill LP tanks.
3. When used in mild climates where the outdoor tem-
perature range is 40 degrees or higher, an LP furnace
is not needed.
SPECIFICATIONS
FIG. 1
LOCATIONS TO
AVOID
NOTE: Geographical location usage should be deter-
mined before omitting a central furnace.
4. The unit is not exposed to the elements.
LOCATION
The system is intended for installation in a Park Model RV
where the interior is essentially one undivided space.
Whenlocatingtheunit,avoidanyareawheretheunitcould
be damaged when transporting. An area to avoid during
mounting is the extreme front and rear of the unit.
SystemModel 39325.502
NominalBTUCapacity (Cool/Heat) 15,000/14,000
Volts/Phase/Hertz 115 / 1 / 60
RunAmpsComp/Motor 12.9 / 4.0
LRACompressor 71
Wire Size Up to 24 ft. -
UseNo. 12 AWG CopperConductors
CircuitProtection 20 Amp Time Delay Fuse or
20AmpHACRCircuitBreaker
Refrigerant R-22
SystemRefrigerantCharge 38.0
Size(In Inches) Width Height Depth
26.25 16.25 19.25
Installed 102Pounds
Weight
Duct Size Supply 42 sq. in. minimum / 60 sq. in. maximum

3
C. SERVICE ACCESS
Be sure NOT to block the inlet or discharge air, or service
access, when mounting.
3. INDOOR SECTION
A. CLEARANCES
The minimum clearances to the evaporator are zero
inchestothebottom,top,leftandrightsides.Accesstothe
electrical connections and drain connection must be pro-
vided when making the installation.
Be sure to allow sufficient room to service the electri-
cal components.
B. INLET AIR
Theevaporatorsection must have free accesstoroomair.
A minimum of 180 square inches of FREE AREA
openingisrequired.Wherethereturnairmustbeprovided
throughlouversor meshscreen,theFREEAREApercent-
age of the material used shall be taken into consideration
when making this determination. An example of how to
determine FREE AREA is included under "2. OUTDOOR
SECTION".
GRILLS AND REGISTERS:
NOTE: The return air grill must have the same square
surface as the coil face (15"H x 17"L).
For each air conditioning system, there must be a
return grill to bring cabin air back into the unit. There
must also be at least four discharge grills per unit.
If floor duct system is used, a minimum duct size of 3"
x 14" (with 2" x 10" floor registers) is recommended for
good air conditioning performance.
Eachreturn air grille mustbefiltered and accessible for
cleaning or replacement.
C. OUTLET AIR:
The 39325 central air conditioning unit is designed to use
a 3" x 14" discharge air duct at a static pressure of .10 to
.25 inches water column. This duct size is necessary to
maintain proper air flow without loss of static pressure and
provide good air circulation.
Allairhandlingducts must beproperlyinsulatedtoprevent
condensation forming on their surface during operation. A
vaporbarrier must also besuppliedon the outer surfaceof
the insulation to prevent moisture from traveling through
the insulation and condensing on the cold ductwork.
8
82
2
2
1/2
1/2
1/2
1/2
36
64
EXAMPLE OF HOW TO DETERMINE FREE
AREA OR % OPEN AREA:
TOTAL AREA =8 X 8 = 64
FREE AREA = 2 X 2 X 9 openings
=36
% OPEN AREA = = 56%
2. OUTDOOR SECTION
The condenser coil is designed to have a fresh supply of
air. If skirting is installed, allow a 15" x 22" opening (330
square inches) for supply air and a 15" x 22" opening (330
square inches) for discharge air. Use the cross flow
method for good air circulation.
DO NOT TOTALLY ENCLOSE THE UNDERSIDE OF
THEUNIT.AIRCIRCULATIONPREVENTSHEAT FROM
BUILDING UNDER UNIT AND YOUR SYSTEM WILL
PERFORM AS DESIGNED.
The condenser section is a "blow-through" type. When
the face of the coil is positioned behind a louvered or
othertypeofrestrictiveopening,theFREEAREAofthe
opening must be at least 260 square inches.
A. FREE AREA — is the opening that remains in a grill or
louvered panel after the restrictions are taken away.
For example, an opening of 10 x 20 inches has 200
squareinches.Whenthisopeningiscoveredwithagrill
that is 56 percent open, the FREE AREA is (200 x .56),
112 square inches.
Expanded and perforated metal grills in general vary from
30percentto60percentopen. Becertainthat 260square
inches of FREE AREA is available to the face of the
condenser.
NOTE: Service access must always be supplied either as
clearance or as a defined access panel.
B. MOUNTING
Vibration eliminators are supplied to prevent the transmit-
tance of vibration into the living area.
The air conditioning unit may be attached to rails beneath
the vehicle, attached to the frame, or mounted directly to
the floor of some vehicles.
Unit should be mounted with a tilt toward the rear (con-
denser) a half-bubble using a level. Unit rear should be
1/4" lower than the front.

4
B. EVAPORATOR SECTION-Line Voltage
1. Remove electrical box cover.
2. Route supply wires through one of the bushings.
3. Routesupplywirethroughtheconnectorandtighten
lock nut to ensure against twisting of the wires.
4. Connect the white wire in the junction box and the
white (neutral) wire from the supply line using an
appropriate wire connector.
5. Connect the black wire in the junction box to black
(hot) wire from the supply line using an appropriate
wire connector.
6. Connect the ground wire from the supply line to the
unit ground screw.
NOTE: Ifthe air conditioning unitisattached to thecentral
furnace, a damper must be installed at the furnace outlet
to prevent cold air from circulating through the furnace
heat exchanger.
4. ELECTRICAL WIRING
NOTE: All wiring must comply with the National
Electrical Code or CSA Standard C22.1, Canadian
Electric Code, Part 1; and all local codes.
A. GENERAL
1. All wiring must be at least 12 AWG.
2. Two conductors plus a ground must be provided from
a supply circuit protected by a 20 AMP slow-blow fuse
or a 20 AMP HACR type circuit breaker to the second
opening at the right of the evaporator section electrical
box.
RETURN SYSTEM
-Risers use interior wall structure
-Using floor joists area for return to unit
-Each return grill is filtered
RETURN
RISER X 2
3" X 14" INSULATED
DUCT (MIN.)
90 SQ. IN.
FILTERED
(MIN. X 2)
DISCHARGE
CONDENSER
AIR
SUPPLYAIR
INSULATED
2" X 10" CLOSEABLE
GRILL (MIN. X 4))
MIN. 180 SQ. IN.
REQUIREDOPENING
ENCLOSED
FLOORJOIST
FLOORING
FLOORCUTOUT
90 SQ. IN. MINIMUM
FLOORCUTOUT
90 SQ. IN. MINIMUM

5
FAILURE TO CORRECTLY WIRE THE UNIT WILL
CAUSE PRODUCT DAMAGE AND MAY CAUSE PER-
SONAL INJURY.
C. A25ft.thermostatcableis supplied with the heatpump
air conditioner. To connect the the thermostat cable to
the heat pump low voltage wires. Follow the Table
below. Secure each connection using a wire nut.
THERMOSTATCABLE HEATPUMP
RED RED
BLUE BLUE
BLACK BLACK
YELLOW YELLOW
BROWN BROWN
WHITE WHITE
VIOLET VIOLET
5. THERMOSTAT MOUNTING
Contact The Dometic Corporation for the proper thermo-
stat kit. The proper location of the thermostat is very
important to ensure that it will provide a comfortable
temperature. Observe the following general rules when
selecting a location.
A. Locate thermostat about 5 feet above the floor;
B. Install thermostat on a partition, not on an outside wall;
C. NEVER expose it to direct heat from lamps, sun or
other heat producing items;
D. Avoid locations close to doors that lead outside, win-
dows or adjoining outside walls;
E. Avoid locations close to supply registers and the air
from them;
F. Never locate thermostat in a room that is warmer or
coolerthantherest ofthecoach—such asthekitchen;
F. The major living area is normally a good location.
THERMOSTAT
WIRES
FIELD
WIRING
WHITE
BLACK
GROUND
6. THERMOSTAT WIRING
A. THERMOSTAT WIRING
Thermostat wiring for Dometic Bimetal thermostat:
Route the (10) conductor cable from the heat pump to the
thermostat location. Leave enough cable within the elec-
trical box to connect to the low voltage cable. At the
thermostat location, leave about six (6") inches of cable
extending through the wall. Plug the thermostat cable into
the thermostat connector cable.
When an auxiliary furnace is used with the heat pump,
a two conductor cable must be routed from the furnace to
the thermostat location. Connect one wire from the fur-
nace to the violet wires with a wire nut. Connect the other
wire from the furnace to the green wire in the thermostat
cable and secure with a wire nut. Tuck the excess wire
backintothe wall and fill opening withinsulationtoprevent
drafts that could affect the thermostat operation. Secure
the thermostat to the wall using the two screws supplied.
B. BIMETAL THERMOSTAT OPERATION
Cooling:
1) Set the SYSTEM SWITCH to COOL.
2) Set the temperature LEVER to your comfort level.
3. Set the FAN switch to:
a) AUTO: The fan cycles off and on with the
compressor.
b) ON: The fan will run continuously. The com-
pressor will turn off when the room temperature is
cool enough to satisfy the thermostat setting.
Heating:
1) Set the system switch to HEAT:
2) Set the temperature LEVER to your comfort level.
3) Set the FAN switch to:
a) AUTO: The fan will cycle off and on with the
compressor.
b) ON: The fan will run continuously. The com-
pressor will cycle off and on with thermostat
demand.
Auxiliary Heat:
1) Set the system switch to AUX.HEAT.
2) Set the fan switch to AUTO.
BIMETAL DIGITAL

6
NOTE: The auxiliary heat position is only used if:
1) You have a factory installed furnace operating
from the heat pump system thermostat.
2) The outside temperature is above40degreesand
you wish to operate your furnace.
3. For quick interior warm up.
4. Thereisno115voltACpoweravailabletooperate
yourheatpump and you must operatethefurnace
for your comfort.
Fan:
To circulate air without heating or cooling:
1) Set the SYSTEM SWITCH to OFF.
2) Set the FAN SWITCH to ON.
Hi/Low:
HIGH: Fan speed position
LOW: Fan speed position
C. THERMOSTAT WIRING
Thermostat wiring for DIGITAL thermostat: Route the
(10)conductorcable from the heat pump tothethermostat
location. Route a two conductor cable from the coach's 12
volt DC power source to the thermostat location. Connect
12 volt positive lead to the green wire on the thermostat
cable.
Connect the 12 DC volt negative lead to the brown lead.
Secure both connections using wire nuts.
At the thermostat location, leave about six (6") inches of
cable extending through the wall. Plug the thermostat
cable into the thermostat connector cable.
There are three display modes: ACTUAL, COOL and
HEAT.
Theoperatormaychoosethemodehedesiresto view
by depressing the "MODE" switch. Each time the
MODE switch is depressed, the display advances to
the next mode. If the display is left in either COOL or
HEAT, the thermostat will automatically return the
display to ACTUAL in approximately three minutes.
A description of the three modes is:
ACTUAL: When in actual mode, the display is indicat-
ing current room temperature.
COOL SET: When in COOL mode, the display is
indicating the current cooling set-point temperature.
At this time the cooling system set-point temperature
may be adjusted up or down to meet the individual's
comfort level. See "Adjusting Set-point" for further
instructions.
HEAT SET: When in the HEAT mode, the display is
indicating the current heating system set-point tem-
perature. At this time, the heating system set-point
temperature may be adjusted up or down to meet the
operator's comfort level. See "Adjusting Set-Point" for
further instructions.
All three display modes can be accessed without
affecting the operation of the system. The system
operation will remain normal unless a change is made
to the set-point to force a change in the system
operation.
2) System Switch: The system switch has four
positions to control the operation of the heating and
cooling systems. They are as follows:
COOL: When in the COOL position, the compressor
will cycle from the cooling system set-point. Blower
operation will be controlled by the position of the
Cooling Fan Switch.
HEAT: When in the heat position, the heating system
will cycle from the heating system set-point. The
heating blower will operate per the heating system
manufacturer specifications.
OFF: When in the OFF position, no thermostat or
system operation will occur. The liquid crystal will
indicate room temperature until backup power is de-
pleted (approximately 2 minutes).
AUXILIARY HEAT:
1) Set the system switch to AUX. HEAT.
2) Set the FAN switch to AUTO.
NOTE: The AUXILIARY HEAT position is only used if:
1) You have a factory installed furnace operating
from the heat pump system thermostat.
2) The outside temperature is above40degreesand
you wish to operate your furnace.
3) For quick interior warm-ups.
4) Thereisno115voltACpoweravailabletooperate
your heat pump and you must operate the furnace for
your comfort.
When an auxiliary furnace is used with the heat pump, a
single wire conductor must be routed from the furnace to
thethermostatlocation.Connectthiswire fromthefurnace
to the violet pigtail at the thermostat and secure with wire
nut.Tucktheexcesswirebackintothewallandfillopening
with insulation to prevent drafts that could affect the
thermostat operation. Using the two screws provided,
secure the thermostat to the wall
NOTE: The furnace has two wires for thermostat connec-
tions. One wire should be marked 12V DC or (+) and the
other wire may be unmarked, or labeled "thermostat". The
wiremarked12V DCor(+)shouldbe cappedandnotused
with the heat pump setup. The wire marked "thermostat"
or the unmarked wire is the wire to connect to the violet
thermostat pigtail. See Wiring Diagram on Page 8.
D. DIGITAL THERMOSTAT OPERATION
Your air conditioner is operated from the control panel of
the electronic wall thermostat. When the furnace is con-
nected to this thermostat, it will operate from the same
control panel.
Identification and operational descriptions for all control
panel switches and display are listed below:
1) LiquidCrystal Display:Thisdisplaywillbeillumi-
nated any time the system is in operation.
The display shows the operator both the mode of the
display (indicated by the arrow at the left side of the
display), and the temperature for that mode.

7
FANSWITCH:TheFanSwitchhasfourpositionsfrom
whichtocontroltheoperationoftheheatpumpblower.
The fan switch controls operation of the blower only
after the system switch is place into the COOL or
HEAT PUMP position.
HIGH AUTO: When in the high auto position, the heat
pump blower operates at high speed and cycles off
and on with the compressor.
LOWAUTO:Wheninlowautoposition,theheatpump
blower operates at low speed and cycles off and on
with the compressor.
HIGH and LOW ON: When in the high or low position,
the heat pump blower operates continuously. The
compressor cycles off and on as needed.
MOMENTARY SWITCHES: There are three momen-
tary switches. Momentary switches are activated by
depressing the center of the switch. A description of
these three switches follows:
MODE: Depressing this switch advances the display
mode from ACTUAL to COOL, HEAT and back to
ACTUAL. When using this switch, you are indicating
your desire to check or adjust the set-point tempera-
tures for cooling or heating. The cool setting deter-
mines the temperature at which the air conditioner will
start to operate. The heat setting determines the
temperature at which the heating system will start to
operate.
UP: Depressing this switch increases the temperature
set-point.
DOWN: Depressing this switch decreases the tem-
perature set-point.
Toadjustthe set-pointforheatingorcooling,pressthe
MODE button until the arrow on the display indicates
the desired set-point you wish to change: COOL or
HEAT.Thedisplaywill indicate the current set-point of
thethermostat.PressUPorDOWN to change the set-
point. Once the new desired set-point is displayed,
press the MODE button until the arrow is pointing to
ACTUAL. If the thermostat is left in the COOL or the
HEATmodethedisplaywillreturntoACTUALinabout
three minutes. After the display returns to ACTUAL, it
takes 15 to 30 seconds for the thermostat to recog-
nized the changes made to the set-point.
7. DUCTS
NOTE: Streamlining of the air duct system means less
resistance to air flow. Sharp angles and turns are to be
avoided.
A. Pressure losses increase as the diameter of the duct is
reduced. When installing your ductwork on long runs,
increase the duct diameter avoid sharp turns.
B. The final evaluation of air distribution in a space is
determined by the occupants' comfort.
C. When building around duct runs or placement of duct
material, DO NOT kink or crush tubing. If turns are
required, maintain largest radii possible to decrease
pressure loss.
8. MAINTENANCE
A. AIR FILTER: Your air conditioner will operate more
efficiently with a clean filter. Replace the filter with a
new one every three months.
B. To maintain efficient operation, the exposed CON-
DENSER COIL should be cleaned as often as neces-
sary to keep it free of dirt and debris. Be careful not to
damage the coil fins when cleaning.
9. SERVICING
If service work is needed, contact your dealer or the
nearest authorized service center. When requesting ser-
vice, always give complete model and serial numbers.
These numbers are located on the left side of the con-
denser bulkhead.
BEFORE YOU CONTACT A SERVICEMAN
Thereare severalbuilt-in featuresthat mayautomati-
cally shut off the unit under abnormal operating con-
ditions. If your unit should shut off, here are some
things you should check before you contact a service
center.
A. Wait a 15 to 30 minutes — to see if unit will resume
operation.
B. Check thermostat to see if it is properly set.
C. Check fuses on electrical supply in the vehicle.
D. Check the filter (indoor section) to see if it is clean.
E. Check the condenser coil to be sure it is clean.
DON'TDO
40°-60°
DO
AIR
FLOW
AIR
FLOW
AIR
FLOW
AIR FLOW
40°-60°
DON'T

8
WIRING DIAGRAM
FURNACE TO THERMOSTAT CONNECTION
2
3
1
1
2
3
5
4
FIELD WIRING
FACTORY WIRING
LINE SPLICE
RC
Y
H
G
NO
RELAY BOARD
COM
COMP
HIGH
FAN
TB8
TB7
FAN
LOW
WHT
PTCR
C
FAN
R
C
S