Make-Up Air Installation Manual

11/23/2011 4 HI309
5. Locate the 24 volt control system “common”. Depending upon heat pump manufacturer, this
could be a “C”, “X” or in some cases “B” screw terminal (probably black or blue wire).
Connect the black (18 gauge) control wire to this common point (this is a “tap” connection).
6. Locate the 1
st
stage call for heat or compressor turn-on wire. This is typically “Y” terminal
(yellow wire). Connect the yellow wire to this terminal (this is a “tap” connection).
7. From the electrical panel breaker specified above, extend the 24Ø power to the bottom right
control box compartment and connect as standard 24Ø volt L1 and L2 power wiring.
8. This power wire must contain a copper safety ground, terminate with green wire.
DUCT SENSOR
This unit is equipped with a remote temperature-sensing probe. This is a solid state probe (actually mini-
micro computer chip at the end of the probe), handle with care.
Suggested installation is in the main warm air stream approximately 20 to 24 airflow inches away from the
electric element. Simply drill a ½” hole in the duct, insert probe, and screw in place.
Comment: The sensor tip within the tube should be at the end of the tube or slightly extending
beyond the tube. If this is not the case, very carefully push the cable (do not grab the sensor tip
with pliers) until the sensor tip can effectively sample the warm air.
This duct sensor has a 6-wire cable, coil and tie excess. It should be connected to the Red, ST, and COM
screw terminals. The “OT” screw terminal is not used for this product application.
WARNING - If the black and red sensor wires are crossed or incorrectly installed at the
terminal block and power is turned on, burnout damage can result within the sensor probe.
ELECTRICAL HOOKUP
240-volt source – from the model number and nameplate determine KW size and amp draw.
According to local codes, building type, wiring length, etc. use appropriate wiring conductor size and
source circuit breaker. Connect to the pigtail wires or terminal block.
Grounding – route and install appropriate size ground conductor between the ground lug and the
building service panel ground bus. This must be a conductor size according to the total amp rating of
the appropriate unit. Conduit is not an adequate ground conductor.
Operation – this unit “turns on” or heats when 24 volts are applied to the yellow and gray wires. Via
an external 24-volt transformer or an external transformer applying 24 volts through a contact (airflow
switch, thermostat, heat pump “Y” wire, etc.) arrange your control circuit to apply 24VAC power
when you want boost heat.