42
Circuit 1:
Terminal 1 is a black wire and is compressor circuit
Terminal 2 is a white wire and is run circuit to compressor.
DO NOT TEST.
Terminal 3 is a red wire and is start circuit to compressor.
DO NOT TEST.
Terminal 4 is a white wire and is 115V common.
Terminal 5 is a brown wire and is fan capacitor circuit to fan
motor.
DO NOT TEST.
Terminal 6 is a black wire and is high fan circuit.
Terminal 7 is a red wire and is low fan circuit.
Terminal 8 is a violet wire and is 115V common.
Terminal 9 is a violet wire and is reversing valve circuit.
This circuit is energized in heat pump mode only.
Note:
DO NOT use a volt meter to do these checks as it
will give erroneous readings.
Circuit 2:
Terminal 1 is an orange wire and is compressor circuit.
Terminal 2 is a gray wire and run circuit to compressor.
DO NOT TEST.
Terminal 3 is a brown wire and is start circuit to compres-
sor.
DO NOT TEST.
Terminal 4 is a white wire and is 115V common.
Terminal 5 is a brown wire and is fan capacitor circuit to fan
motor.
DO NOT TEST.
Terminal 6 is a black wire and is high fan circuit.
Terminal 7 is a red wire and is high fan circuit.
Terminals 8 & 9 are open.
Note:
The circuit 2 AC power module board is the one that
is staged and will have a delay fro the Circuit 1 system.
Verify that Circuit 2 should be operating before start of di-
agnosis.
Note:
DO NOT use a volt meter to do these checks as it
will give erroneous readings.
C18. Thermostat
There are four types of thermostats used on Duo-Therm
units. Each type is explained in this section.
C18a.
Mechanical
Thermostat
The mechanical thermostat used for air
conditioners has 2 terminals. It controls
the on and off cycling of the compres-
sor. The air temperature of 65° F or less
around the sensor tube will not allow
the compressor to start and over 90°
F, the compressor will run constantly.
To check the thermostat for operation,
turn the air conditioner breaker off, and
disconnect the wires to the thermostat.
Section C - Components, cont’d.
FIG. C40
Turn the control knob clockwise to cooler. You should have
continuity. Turn the thermostat knob counter clockwise to
warmer and no continuity should be present. This type is
used on the mechanical series of heat pumps. The ther-
mostat controls the ON/OFF cycling of the compressor. It
has three terminals. Air temperature between 65° F and
90° F will allow the thermostat to cycle the compressor. In
the heat pump mode the compressor will not shut off if the
temperature is below 65° F, unless the changeover ther-
mostat reaches 40° F. See Section C10, page 32. If the
temperature is over 90° F, the compressor will not operate
in the heat pump mode. The reverse is true for air condi-
tioning operation. To check the thermostat for operation,
turn the heat pump circuit breaker off, and disconnect the
wires to the thermostat. Turn the control knob to COOLER.
You should have continuity between Terminals 2 to 3 and
no
continuity between Terminal 2 to 1. Turn the thermostat
to WARMER. You should
not
have continuity between Ter-
minals 2 to 3; and have continuity between Terminal 2 to 1.
If you have incorrect readings, replace the thermostat. If
you have the readings as indicated above, DO NOT re-
place the thermostat.
C18b.
Bimetal Thermostat
This thermostat is designed to operate 12V DC single-stage
heat pump and an independent single-stage auxiliary heat
system. It is a manual changeover thermostat between
heating, cooling and auxiliary heat. Operating temperatures
for both heating and cooling systems are changeable to
suit the comfort needs of the occupants.
This thermostat is used for a remote wall mounted thermo-
stat. The heat pump can have an air distribution box or a
ducted system. Next, verify wiring to the thermostat is cor-
rect.
Thermostat Wiring for Dometic Bimetal Thermostat:
Route the (10) conductor cable from the 14" x 14" opening
to the thermostat location. Leave enough cable within the
14" x 14" opening to connector 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 furnace
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 back into
the wall and fill opening with insulation to prevent drafts
that could affect the thermostat operation. Secure the ther-
mostat to the wall using the two screws.
Note:
Verify the heat anticipator is set properly for the aux-
iliary furnace. Failure to set the anticipator can cause in-
correct operation or failure of thermostat in AUX HEAT or
HEAT PUMP setting.
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
