Lennox GCS16-413-100

Page 73
E-W973 Control System
The W973 is used only with the C8 and C14 control sys
tem options. It cannot be used with any other control sys
tem options or control damage will result.
The Honeywell W973 control, when added to the GCS16,
allows the use of electronic ramping thermostats, dis
charge temperature sensors, return air temperature sen
sors and/or remote thermostats and transmitters. The
W973 control system is designed for use with Honeywell
T7067 electronic ramping thermostat and Q667 subbase.
An interconnecting W973 relay kit must be used to adapt
the W973 to the GCS16. Optional CMC3-1 time clock
must also be used for night setback capabilities. The relay
kit changes the thermostat setpoints for night setback. A
night thermostat is not needed.
1-W973 Control
(C8 and C14 control systems)
No wiring is required (see figure 97). Disconnect
Jumper J16 from plug P16. Connect W973 plug P17
to unit jack J16. Connect W973 jack J17 to unit plug
P16. Jumper plug J19 supplied with the W973 must
be connected to plug P19 on the W973. Jumper
plug J12 (also supplied with the W973) is not used
with GCS16s and may be discarded.
2-W973 Relay Kit
units without economizer or units
with economizer and without warmup
(C8-1 and C8-3 control systems)
No wiring is required (see figure 98). Disconnect
unit plug P3 from unit jack J3 but do not discard.
Plug P3 must be used if unit is not equipped with
economizer. Connect relay kit plug P6 to unit jack
J3.
If unit is not equipped with economizer, connect
relay kit J6 to unit plug P3.
If unit is equipped with economizer, connect relay kit
plug P6 to economizer jack J4.
3-W973 Relay Kit with WarmUp
units with economizer and warmup
(C14-1 control system)
No wiring is required (see figure 99). Unit plug P3 is
removed from unit and discarded. Connect W973
relay kit plug P6 to unit jack J3. Connect W973 relay
kit jack J6 to warmup kit plug P8. Connect warmup
kit jack J8 to economizer plug P4.
FIGURE 97
HONEYWELL W973 CON
TROL
INSTALLATION
GCS16 UNIT
SUPPLY AIR
BLOWER
HARNESS FROM UNIT
DOWNFLOW
RETURN AIR
OPENING
CONTROL MOUNTING BRACKET
HORIZONTAL UNITS
CONTROL MOUNTING BOX
DOWNFLOW UNITS
P3J6 J3P6 P17J16
P16
J17
W973 CONTROL
W973 RELAY KIT
W973 RELAY KIT
W973 CONTROL