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LGM/LCM036, 048, 060, 074
C-Hot Gas Reheat
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 16 for
Thermostat Mode or figure 15 for Zone Sensor
Mode. In addition, connect either a humidity
sensor or a dehumidification input. See figure 17
or 18 for humidity sensor wiring or figure 19 for
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 the Unit
Controller as shown in figure 17.
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 17.
FIGURE 17
FIELD WIRING REHEAT UNITS (Using A Humidity
Sensor With Less Than 150 Ft. Wire Runs)
9
8
10
11
12
J262B
5
P298
J298A
1
2
B
3
4
C
5
6
7
D
A91
VIN
VO
GND
P262
R
C
AI
−
1
HUM
TMP
DO
−
1
C
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 18. Use two shielded
cables containing 20AWG minimum, twisted pair
conductors with overall shield. Belden type 8762 or
88760 (plenum) or equivalent.
FIGURE 18
FIELD WIRING REHEAT UNITS
(Using A Humidity Sensor With
More than 150 Ft. Wire Runs)
ISOLATED 24V
TRANSFORMER
9
8
P298
J298A
1
2
B
3
4
C
5
6
7
D
10
A91
VIN
VO
GND
R
C
AI-1
HUM
TMP
DO-1
C
DI-1
DO-2
NOT
CONNECTED
NOT
CONNECTED
DRAIN
A55 UNIT
CONTROLLER
FIGURE 19
FIELD WIRING REHEAT UNITS
(Using A Dehumidification Switch)
7
10
8
9
R
DI
−
4
C
Use 24 VAC (R) from any terminal
available on J299
−
2,
−
5, or
−
7.
J299
DEHUMIDIFICATION
SWITCH
