43
Section C - Components, cont’d.
Before checking the thermostat for operation, first deter-
mine that the thermostat is receiving DC power from the
relay board then disconnect the cable assembly from the
back of the thermostat.
Next, use a DC voltmeter and check from red wire or Pin 2
on cable assembly (positive [+] lead from voltmeter) to
brown wire or Pin 7 (negative [-] lead from voltmeter). You
should get a voltage reading of approximately 12V DC. Next,
move the negative (-) lead from the voltmeter to each of
the following wires or pins:
Blue (Pin 6), Yellow (Pin 5), Black (Pin 4), White (Pin 3).
You should get a voltage reading of approximately 12V DC
on each wire. This indicates the relay board and cable as-
sembly are providing proper power and circuits to the ther-
mostat.
Note:
Pin 2 (red wire) is positive DC volts when ambient
(outside) air is above 40°F. Pin 1 (violet wire) is positive DC
volts when ambient (outside) air is below 40°F.
If the voltage checks are correct and the unit does not op-
erate correctly, check the thermostat. If the voltage checks
are not as described, check the relay board (Section C17a
and the cable assembly - C19).
To check the thermostat, first remove it from its mounting
on the wall. Then disconnect the thermostat assembly from
the cable assembly in the wall. Now you are ready to do a
continuity check on the thermostat assembly. Place the
positive (+) lead from the ohm meter on red wire (Pin 2)
and negative (-) lead from the ohm meter to the active pin
or wire to read continuity.
Polarity is important for proper
check to be done.
With System Switch in COOL, Fan Switch in HI AUTO and
room temperature ABOVE setpoint temperature, you should
have continuity between red wire (Pin 2) to black wire (Pin
4), yellow wire (Pin 5) and blue wire (Pin 6). You should
NOT have continuity between red wire to violet or white
wires.
FIG. C41
FIG. C42
With room temperature BELOW setpoint temperature, you
should NOT have continuity between red wire to violet,
white, black, yellow or blue wires.
With System Switch in COOL, Fan Switch in LOW AUTO
and room temperature ABOVE setpoint temperature, you
should have continuity between red wire (Pin 2) to black
wire (Pin 4) and yellow wire (Pin 5). You should NOT have
continuity between red wire to violet, white or blue wires.
With room temperature BELOW setpoint temperature, you
should NOT have continuity between red wire to violet,
white, black, yellow or blue wires.
With System Switch in COOL, Fan Switch in LOW ON and
room temperature ABOVE setpoint temperature you should
have continuity between red wire (Pin 2) to black wire (Pin
4) and yellow wire (Pin 5). You should NOT have continuity
between red wire to violet, white, or blue wires. With room
temperature BELOW setpoint temperature, you should
have continuity between red wire (Pin 2) to black wire (Pin
4 ). You should NOT have continuity between red wire to
violet, white, yellow or blue wires.
With System Switch in COOL, Fan Switch in HI ON and
room temperature ABOVE setpoint temperature you should
have continuity between red wire (Pin 2) to black wire (Pin
4), yellow wire (Pin 5) and blue wire (Pin 6). You should
NOT have continuity between red wire to violet or white
wires. With room temperature BELOW setpoint tempera-
ture, you should have continuity between red wire (Pin 2)
to black wire (Pin 4) and blue wire (Pin 6). You should NOT
have continuity between red wire to violet, white or yellow
wires.
With System Switch in OFF, Fan Switch in HI AUTO or
LOW AUTO and room temperature ABOVE or BELOW
setpoint temperature, you should NOT have continuity be-
tween red wire to violet, white, black, yellow or blue wires.
With System Switch in OFF, Fan Switch in LOW ON and
room temperature ABOVE or BELOW setpoint tempera-
ture, you should have continuity between red wire (Pin 2)
to black wire (Pin 4). You should NOT have continuity be-
tween red wire to violet, white, yellow or blue wires.
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
