37
Section C - Components, cont’d.
There are four relays used in Models 39224 and 39424.
Two are used in the reversing valve circuit and are desig-
nated as HR (heat relay) on the wiring diagram. Two are
used in the furnace blower circuit and are designated as
FB (furnace blower) on the wiring diagram.
C16i.
Relay, 2-Pole Furnace Blower
The relay is used on basement air conditioner Model 39125
and Basement heat pump Model 39335 ONLY. The relay
has five (5) terminals.
It is used to complete a circuit to
the furnace.
Terminals 1 and 3 are the coil terminals. When the coil
(terminals 1 and 3) is not energized (no power to terminals
1 and 3), continuity should exist between terminals 4 to 5;
and no continuity between terminals 2 to 4.
FIG. C30
When the coil (terminals 1 and 3) is energized (power to
terminals 1 and 3), continuity should exist between termi-
nals 2 to 4 and no continuity between terminals 4 to 5. This
relay is used to energize the furnace blower any time the
compressor is energized. This circuit has been added to
enhance both the cooling and heating operation.
Note:
This circuit will not work with all furnaces.
Before using this circuit, check with the furnace manufac-
turer for proper wire connection to the furnace. Other com-
ponents may or may not be required. Read and follow the
instructions provided with the furnace.
Instructions for Furnace Connections
The following furnace connection instruc-
tions only pertain to one specific furnace
manufacturer, and may not apply to your in-
stallation.
Run a 12 volt DC positive lead to one of the gray wires in
the unit electrical box and secure with an approved con-
nector.
Run a second lead from the furnace blower motor or termi-
nal board to the remaining gray lead in the unit electrical
box. Secure with an approved connector.
C16j.
Relay, (DPST)
The relay is a double pole, single throw and controls the
fan motor in the roof mounted unit. When the AUX HEAT
mode is selected or the outside temperature is too cold for
HEAT PUMP operation and automatically goes to auxiliary
operation, the relay will interrupt the circuit to the fan mo-
tor.
When COOL, OFF and HEAT PUMP modes are selected,
the relay coil is not energized. When AUX HEAT mode is
selected the relay coil is energized with 12V DC.
To check the relay, first remove the wires form COM and
NC terminals. Next verify the relay coil is not energized (no
DC power), continuity should exist between terminals COM
and NC and no continuity between terminals COM and NO.
Next energize the relay coil with DC volts (10 to 16). Conti-
nuity should exist between COM and NC, If the above
checks are correct, the relay is good - DO NOT replace it.
If the above checks are not correct, the relay is defective
and should be replaced.
Note:
Verify the thermostat is wired properly from the fur-
nace, as incorrect polarity on the furnace thermostat wires
will energize the relay coil and keep the fan motor from
operating in the roof mounted unit.
C16k.
Relay, Double Throw
The relay controls AC power to the reversing valve. There
are two different relays used. One relay has a 12V DC rated
coil and is used on all Duo-Therm Heat Pumps except the
mechanical control types. The mechanical control Duo-
Therm Heat Pumps use a relay that has a 120V AC rated
coil. Both relays have five (5) terminals.
Terminals 1 and 3 are the coil termi-
nals. When the coil (terminals 1 and
3) is not energized (no power to termi-
nals 1 and 3), continuity should exist
between terminals 4 to5; and no conti-
nuity between terminals 2 to 4.
When the coil (terminals 1 and 3) is
energized (power to terminals 1 and
3), continuity should exist between ter-
minals 2 to 4 and no continuity between
terminals 4 to 5.
FIG. C31
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com
