Wiring Diagrams - Lennox ComfortSense L7742U Programming Manual

Wiring Diagrams

Thermostat wiring connections with various units, including dual fuel, zone control, and applications that include the Humidi-
®
trol Enhanced Dehumidification Accessory (EDA). See figures 18 and 19.
Figure 18. Typical Condensing Unit/Humiditrol
WHEN 2−STAGE HEAT IS USED, T'STAT IS
CONFIGURED FOR 2−STAGE HEAT, CONNECT 2ND
STAGE HEAT BULB TO TERMINAL W2 & REMOVE
JUMPER BETWEEN R & W2.
CUT ON−BOARD LINK (CLIPPABLE CONNECTION)
FROM DS TO R (W914) WHEN DEHUMIDIFICATION
OR HARMONY CONTROL IS USED.
DO NOT CUT ON−BOARD LINK (CLIPPABLE
CONNECTION) FROM R TO O (W951). IT IS USED
FOR CONDENSING UNIT APPLICATIONS.
REMOVE R TO O JUMPER IN HEAT PUMP
APPLICATIONS.
REMOVE DS TO Y1 JUMPER WHEN
DEHUMIDIFICA TION D TERMINAL IS USED.
OUTDOOR SENSOR FOR OUTDOOR TEMP. DISPLAY,
DEW POINT CONTROL, HEAT PUMP BALANCE
POINTS & DUAL FUEL BALANCE POINTS.
RED WIRE TO OUTDOOR CONDENSING UNIT USED
ONLY FOR UNITS WITH LSOM & FOR ALL HEAT
PUMPS.
BROWN WIRE USED ONLY ON UNITS WITH LSOM.
FOR HUMIDIFIER, 48G95 (OR EQUIVALENT)
ISOLATION RELAY REQUIRED (COIL 24VAC, 5VA
MAX.). CAN BE USED WITH ALL T'STAT
APPLICATIONS.
CUT ON−BOARD LINK (CLIPPABLE CONNECTION)
FROM Y1 TO Y2 (W915) FOR 2−STAGE COOLING.
K183 DEHUMIDIFICATION RELAY KIT (26W62)
REQUIRED WHEN USING D TO DS TERMINALS WITH
CB(X)27 UNITS.
NOTE: NOT ALL UN-
USED TERMINALS ARE
SHOWN ON T'STAT
DIAGRAMS.
OUTDOOR
SENSOR
(X2658)
RED
RED
PUR
BLK
PUR
BLK
EDA UNIT
FAN
RELAY
YEL
BLU
BLK
BRN
Y1 Y2 JUMPER − IN FOR
SINGLE− STAGE COOLING;
OUTDOOR
REMOVED FOR 2−STAGE
UNIT
COOLING
NOTES −
/1\ NOT REQUIRED FOR APPLICATIONS WITHOUT LSOM
/2\ NOT REQUIRED WITH SINGLE-SPEED OUTDOOR FAN)
/3\ NOT REQUIRED FOR SINGLE STAGE
Figure 19. Thermostat Wiring Diagrams
L7742U
INDOOR
THERMOSTAT
UNIT
®
Accessory Wiring Diagram
Page 19
DUAL FUEL
FURNACE SETUP
CUT ON−BOARD LINK
(CLIPPABLE CONNECTION)
FROM R TO O (W951).
CUT ON−BOARD LINK
(CLIPPABLE CONNECTION)
FROM R TO DS (W914).
WITH DEFROST
TEMPERING, SET W2 TO
TIMED ON.
ComfortSenset Model L7742U Touch Screen
7−Day Programmable Thermostat