Lennox LCH036 Installation Instructions Manual page 63

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 the Unit
Controller as shown in figure 15.
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 the Unit
Controller as shown in figure 15.
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 16. Use two shielded cables
containing 20AWG minimum, twisted pair conductors
with overall shield. Belden type 8762 or 88760 (plenum)
or equivalent.
FIELD WIRING HOT GAS REHEAT UNITS (Using A
Humidity Sensor With Less Than 150 Ft. Wire Runs)
NOT
CONNECTED
A91
VIN
GND
DRAIN
VO
NOT
CONNECTED
FIGURE 15
A55 UNIT
CONTROLLER
P298
J298A
1
2
B
3
4
C
5
6
7
D
8
9
10
UNUSED
WIRE
FIELD WIRING HOT GAS REHEAT UNITS (Using A
Humidity Sensor With More than 150Ft. Wire Runs)
NOT
CONNECTED
A91
VIN
GND
VO
R
C FIELD WIRING HOT GAS REHEAT UNITS
(Using A Dehumidification Switch)
AI-1
HUM
DEHUMIDIFICATION
SWITCH
TMP
DO-1
C
DO-2
DI-1
Page 13
ISOLATED 24V
TRANSFORMER
J298A
1
DRAIN
2
B
NOT
3
CONNECTED
4
C
5
6
7
D
8
9
10
FIGURE 16
J299
7
8
9
10
Use 24 VAC (R) from any terminal
available on J299−2, −5, or −7.
FIGURE 17
A55 UNIT
CONTROLLER
P298
R
C
AI-1
HUM
TMP
DO-1
C
DO-2
DI-1
R
DI−4
C