Lennox GCS16-653-125

Page 70
C-W7400 Control System
The W7400 is used only with the C7 control system option.
It cannot be used with any other control system option or
control damage will result.
The Honeywell W7400/T7400 control system, when ap
plied to the GCS16, allows fully programmable operation
of the unit during occupied and unoccupied periods.
Morning warmup capabilities are built in to the control
system. An external warmup kit is not needed.
1-W7400 Control
No wiring is required (see figure 94). Disconnect
Jumper J16 from plug P16. Connect W7400 plug
P17 to unit jack J16. Connect W7400 jack J17 to unit
plug P16.
For basic unit operation without economizer, unit
plug P3 must be connected to unit jack J3.
2-W7400 Relay Kit
An economizer may be added to the system to allow out
side air for cooling. W7400 relay kit must be added to inter
face the control to the economizer.
WARNING - CONNECT ONLY RELAY KITS DE
SIGNED FOR THIS CONTROL SYSTEM. RELAY
KITS DESIGNED FOR OTHER CONTROL SYS
TEMS ARE NOT COMPATIBLE AND CONTROL
DAMAGE OR FAILURE WILL RESULT. FOR EXAM
PLE, DO NOT CONNECT A W973 RELAY KIT TO
THIS CONTROL SYSTEM.
CAUTION - DO NOT CONNECT A WARMUP KIT
TO JACK J5 OF THE W7400 RELAY KIT. Warmup
kit wiring is not compatible with W7400 wiring and
COMPONENT DAMAGE WILL RESULT. The W7400
system has a warmup feature built in. A warmup
kit is not needed.
No wiring is required (see figure 95). Unit plug P3 is re
moved and discarded. Relay kit plug P5 connects to unit
jack J3. Economizer plug P4 connects to relay kit jack J5.
FIGURE 94
HONEYWELL W7400 CONTROL INSTALLATION
GCS16 UNIT
SUPPLY AIR
W7400 CONTROL
P3
W7400 RELAY KIT
J3P5 J17
P16
P17
J16
BLOWER
HARNESS FROM UNIT
J5
DOWNFLOW
RETURN AIR
OPENING
CONTROL MOUNTING BRACKET
HORIZONTAL UNITS
CONTROL MOUNTING BOX
DOWNFLOW UNITS
W7400 CONTROL