Thetford EV704D Series - Manual (Page 3)

INSTALLATION
In preparing the DE-704D for installation, the following areas
should be considered:
1. Adequate ventilation.
2. Sizing of supply wire and fuse protection.
3. Direct wiring from battery to avoid electrical interference
with other equipment.
4. Provisions to prevent battery run-down.
5. Provide correct voltage and frequency for AC operation.
6. Proper grounding to prevent electrolysis for marine applica-
tions.
These instructions provide a guide to insure compliance to the
situations listed above.
The Norcold dual voltage refrigerator is designed for the recrea-
tional vehicle, Marine industry, as well as under the counter instal-
lations. A typical R.V. installation, for instance, requires the refrig-
erator to operate on 12 volt DC while in transit and 120 volt AC
while parked. The Norcold refrigerator automatically converts from
one power source to the other.
Unlike the absorption-type refrigerator, which requires a constant
heat source for efficient operation, your dual voltage refrigerator
operates on the same principle as the standard domestic refrigera-
tor. That is, it has an electrically operated compressor and uses
freon as its refrigerating medium.
Unit Location
Be sure the refrigerator is not installed in direct sunlight, or near
a gas stove, heater or other heat generating sources. A flanged
mounting frame is provided around the front of the refrigerator
cabinet to allow build-in installation.
The refrigerator must be located and secured on a solid surface
within the vehicle.
The opening cut-out dimensions for the refrigerator are listed in
Table 1. Measure for the opening and determine if you have the
proper clearances for installation. There is no need for allowing an
area around the cabinet for additional insulation as the Norcold
refrigerator is well insulated and requires no additional insulation.
Table 1
Before installing the cabinet into the opening, check to see if the
AC power supply cord of the unit is properly connected to the AC
wall outlet and if the DC supply should be connected. In many
cases, the DC supply can be connected from outside the vehicle
by means of the vent or access door.
Place the refrigerator into the wall opening and secure it in place
by fastening the mounting flange to the wall through the holes
provided.
Please note the perforated access panel at the front base of the
refrigerator. This panel allows air movement to flow under the
cabinet and over the power supply for cooling.
The rear side of the unit must not be closed off without providing
ventilation. At least 50 sq. inches must be provided to allow re-
jected heat to escape.
For travel trailers, a small louver-type vent of approximately 4" x
16" area may be installed at the top and at the bottom of the
exterior wall of the vehicle for outside venting purposes.
A combination of a roof jack and lower vent or two side vents
offers adequate venting for high outside ambient temperatures.
The more air circulating over the condenser (located at rear), the
more efficient the refrigerator will operate. Failure to provide the
necessary ventilation will result in poor refrigeration. If operation at
low outside ambient temperatures is necessary (below 23° F) all
exterior venting must be covered to prevent serious performance
loss.
When installation incorporates exterior venting and operation at
low outside ambient temperatures is necessary (below 23° F), ex-
terior venting must be covered or reduced cooling efficiency in
cabinet will result.
Power Supply
Provisions are made for connection of either 12 volts DC or 120
volts AC to the refrigerator. If both 12 volts DC and 120 volts AC
are simultaneously supplied, a special relay in the refrigerator
power supply allows the unit to run on 120 volts AC. To convert to
DC power, the AC supply is simply disconnected.
DC Power Connection
The DC supply connection is located behind the perforated ac-
cess panel at the bottom front of the unit. Remove the screw from
the top center of the access panel and remove the panel. The DC
terminal box is located in the control power supply assembly. The
positive and negative DC supply connections are located in this
terminal box. The terminal box is provided with knock-out holes for
routing the DC lead wires through the side of the terminal box.
The size of the wire from your 12 volt DC battery is dependent
upon the distance between the refrigerator and the battery. Refer
to Table 2 for wire size.
Table 2
This recommended wire size is to prevent a voltage drop at the
refrigerator which is critical to DC performance.
Use of wire sizes smaller than those listed may cause excessive
DC running time, shorter battery life, and poor performance due to
line loss.
It is important that the 12 volt, DC supply wires be connected
directly to the battery and that the wires are dedicated to the re-
frigerator (other appliances are connected by separate wires). This
practice minimizes the possibility of radio and T.V. interference.
Twisting the positive and negative supply wires further helps to
nullify the induction effects which could further add to radio/T.V.
interference.
To the leads located in the terminal box, connect the positive
battery lead to the red wire and the negative battery lead to the
black wire (important to be well insulated). These splices should
be soldered or connected by means of an approved splice con-
nector. Tape the spliced connections generously before replacing
the terminal cover box.
A 15 amp fuse should be installed as close to the battery as
possible in the positive wire leading to the refrigerator. This fuse
will protect the wiring from the battery to the refrigerator in the
event of a short circuit.
CAUTION:
DO NOT OPERATE REFRIGERATOR ON BATTERY ALONE.
THE BATTERY MUST HAVE A CHARGING MEANS SUCH AS
AN ON-BOARD GENERATOR; IF NOT, THE BATTERY WILL
DISCHARGE IN A SHORT PERIOD OF TIME.
Refrigerator Cut-Out Opening (inches)
Model Height Width Depth
DE-704D 33 1/8 22 21 3/4
12 Volt Supply Wiring And Fuse Size
Min. Wire Max. Fuse
Size Size
0 -12’ 14 AWG 15 AMP
12’ - 20’ 12 AWG 15 AMP
over 20’ 10 AWG 15 AMP
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