Bard QTEC QH244D, Installation Instructions Manual

Page: 16 / 40

Manual 2100-435F
Page
16 of 40
LOW VOLTAGE CONNECTIONS
These units use a grounded 24 volt AC low voltage
circuit.
The “R” terminal is the hot terminal and the “C”
terminal is grounded.
“G” terminal or pin 6 of P4 is the fan input .
“Y” terminal or pin 7 of P4 is the compressor input .
“B” terminal or pin 8 of P4 is the reversing valve input .
The reversing valve must be energized for heating
mode.
“R” terminal or pin 10 of P4 is 24 VAC hot .
“C” terminal or pin 11 of P4 is 24 VAC grounded.
“L” terminal or pin 12 of P4 is compressor lockout
output . This terminal is activated on a high or low
pressure trip by the electronic heat pump control. This
is a 24 VAC output.
“W2” terminal or pin 9 of P4 is second stage heat (if
equipped). If the unit is equipped with an optional hot
water coil plenum box the water valve will be connected
to this terminal.
“O1” terminal of pin 5 of P4 is the ventilation input .
This terminal energizes any factory installed
ventilation option.
“E” terminal or pin 3 of P4 is the emergency heat input.
This terminal energizes the emergency heat relay.
NOTE: For total and proper control using DDC, a total
of 7 controlled outputs are required (6 if no
ventilation system is installed). For proper
system operation under Emergency Heat
conditions where the compressor needs to be
deactivated, the B-W2-E outputs need to be
energized. Removing the Y (compressor) signal
alone turns the compressor off, but does not
activate the additional circuitry embedded in
the heat pump for proper and complete
operation.
“5” terminal or pin 2 of P4 is the 24 dehumidification
circuit.
“4” terminal of pin 4 or P4 is the dehumidification
circuit . A contact must connect terminals 4 and 5.
“6” terminal of pin 1 of P4 is VAC grounded to the
humidistat , if needed.
GENERAL
This unit is equipped with a variable speed ECM motor.
The motor is designed to maintain rated airflow up to
the maximum static allowed.
It is important that the
blower motor plugs are not plugged in or unplugged
while the power is on. Failure to remove power prior
to unplugging or plugging in the motor could result in
motor failure.
CAUTION
Do not plug in or unplug blower motor
connectors while the power is on. Failure to do
so may result in motor failure.
LOW VOLTAGE CONNECTIONS
FOR
DDC CONTROL
Fan Only Energize G
Cooling Mode Energize Y, G
Heat Pump
Heating
Energize Y, G, B
2nd Stage Heating Energize G, W2, Y, B
(if employed)
Ventilation Energize G, O1
Dehumidification Connect 4 & 5
Emergency Heat Energize B, W2, E, G