Hot Gas Reheat Units Only; Humidity Sensor Cable Applications - Lennox LGH180H Installation Instructions Manual

FIELD WIRING IN ZONE SENSOR MODE
(Zone Sensor Mode)
UNIT CONTROLLER
SENSOR
24VAC
SENSOR
IAQ
R C
AI1 HUM
A2 SENSOR
FIGURE 9
D-Hot Gas Reheat Units Only
1- Install humidity sensor in accordance with instructions
provided with sensor. A DDC input may be used to
initiate dehumidification instead of a sensor.
2- Make wiring connections as shown in figure 8 for
Thermostat Mode and figure 9 for Zone Sensor
Mode. In addition, connect either a humidity sensor
or a dehumidification input. See figure 10 or 11 for
humidity sensor
dehumidification input wiring.

Humidity Sensor Cable Applications:

Wire runs of 50 feet (mm) or less:
Use two separate shielded cables containing 20AWG
minimum, twisted pair conductors with overall shield.
Belden type 8762 or 88760 (plenum) or equivalent.
Connect both cable shield drain wires to TB1-7 as shown
in figure 10.
Wire runs of 150 feet (mm) or less:
Use two separate shielded cables containing 18AWG
minimum, twisted pair conductors with overall shield.
Belden type 8760 or 88760 (plenum) or equivalent.
Connect both cable shield drain wires to TB1-7 as shown
in figure 10.
Wire runs over 150 feet (mm):
Use a local, isolated 24VAC transformer such as Lennox
cat #18M13 (20VA minimum) to supply power to RH
sensor as shown in figure 11. Use two shielded cables
containing 20AWG minimum, twisted pair conductors
with overall shield. Belden type 8762 or 88760 (plenum)
or equivalent.
LGH/LCH156, 180, 210, 240, 300S
OUTPUTS
TMP
D01 D02
J298
wiring and figure 12
FIELD WIRING REHEAT UNITS (Using A Humidity
Sensor With Less Than 150 Ft. Wire Runs)
NOT
CONNECTED
A91
VIN
GND
DRAIN
VO
NOT
CONNECTED
FIELD WIRING REHEAT UNITS (Using A Humid­
ity Sensor With More than 150 Ft. Wire Runs)
NOT
CONNECTED
ISOLATED 24V
TRANSFORMER
A91 DRAIN
for
VIN
CONNECTED
GND
VO
FIELD WIRING REHEAT UNITS
(Using A Dehumidification Switch)
DEHUMIDIFICATION
SWITCH
Use 24 VAC (R) from any terminal
available on J299−2, −5, or −7.
Page 12
P298
J298A
1
2
B
3
4
C
5
6
7
D
8
9
10
UNUSED
WIRE
FIGURE 10
CONTROLLER
P298
J298A
1
2
B
NOT
3
4
C
5
6
7
D
8
9
10
FIGURE 11
J299
7 R
8 DI−4
C
9
10
FIGURE 12
A55 UNIT
CONTROLLER
R
C
AI-1
HUM
TMP
DO-1
C
DO-2
DI-1
A55 UNIT
R
C
AI-1
HUM
TMP
DO-1
C
DO-2
DI-1