Wiring Requirements; Choosing Thermostat Location - Dometic 57908.321 Installation Instructions Manual

INSTALLATION INSTRUCTIONS
FIG. 7
D.

Wiring Requirements

1.  R oute a copper, with ground, 120 Vac supply
wire from the time delay fuse or circuit breaker
box to the roof opening. Use a listed/certified
non metallic - sheathed single strand cable. See
"A. Table - Unit Data" on page (4).
a. This supply wire must be located in the front
portion of the roof opening.
b. The power MUST be on an appropriately
sized separate time delay fuse or circuit
breaker. See "A. Table - Unit Data" on page
(4).
c. Make sure that at least 15" of supply wire
extends into the roof opening. This ensures
an easy connection at the junction box.
d. Protect the wire where it passes into the
opening with approved method.
2. 12 volt DC supply comes from control box.
3. Thermostat Communication Cable
a. LCD SZ Thermostat
I. Route a 3 conductor communication ca-
ble, 18-22 AWG, from the roof opening
to the Liquid Crystal Display Single Zone
(hereinafter referred to a LCD SZ) ther-
mostat mounting location. Make sure that
at least 15" of the wire extends into the
roof opening and 15" extends from the
wall at the thermostat mounting location.
See "E. Choosing Thermostat Location"
on page (8).
Duct Size And Requirements For 3105007.XXX And 3105935.XXX RAG
4. If system includes a gas furnace, route two 18-
22 AWG thermostat wires from the furnace to
the roof opening of the unit that will control it.
If more than one furnace is to be used, route
the second set of thermostat wires to the second
unit. Make sure that at least 15" of wire extends
into the opening.
 I f converting from Bi-Metal Thermostat to
Single Zone Thermostat, see "I. LCD SZ
System Low Voltage Wire Connections"
on page (12) for wiring details.
E.

Choosing Thermostat Location

1. LCD SZ system
a. The proper location of the thermostat is very
important to ensure that it will provide a com-
fortable RV temperature. Observe the follow-
ing rules when selecting a location.
● Locate the thermostat 54" above the floor.
● Install the thermostat on a partition, not
on an outside wall.
● NEVER expose the thermostat to direct
heat from lamps, sun, or other heat pro-
ducing items.
● Avoid locations close to doors that lead
outside, windows, or adjoining outside
walls.
● Avoid locations close to supply registers
and the air from them.
8
Register Required
Registers
4 Min - 8 Max.
(Per Unit)
14 Sq. In. Free
Area Per Register