Lennox GCS16-653-125

Page 65
S-Commercial Controls Hardware
(GCS16 Commercial Units Only)
All GCS16 commercial units (GCS16R and GCS16H ex
cluded) are factory equipped with the hardware required to
connect and operate Lennox' Commercial Controls
(W973, W7400, economizer, warm-up, etc...). The hard
ware consists of an economizer wiring harness (figure 83),
low voltage terminal strip, discharge line high pressure,
loss of charge switches and crankcase heater.The
switches, crankcase heater and terminal strip are detailed
in the unit components section of this manual. The econo
mizer harness is a prewired harness which facilitates
economizer, controls and/or warmup connections.

T-Optional Commercial Controls Systems
Optional 16 Series Commercial Controls" may be con
nected to all GCS16 commercial units (GCS16R and
GCS16H excluded). These are the same controls which
are optional to larger GCS16 commercial units. The fol
lowing list describes the components used in all currently
available (at time of printing) optional control system com
binations. Each system is assigned a C" number for easy
reference.The C" number identifies the control system on
the wiring diagram (likewise, each GCS16 unit wiring dia
gram is assigned a B" number and each economizer dia
gram is assigned a D" number).
The following section is provided to help service personnel
become familiar with Lennox' Commercial Controls and
the associated wiring schemes.
1- D5 - Modulating Economizer
Horizontal or Downflow Modulating Economizer. Op
tional field installed in all GCS16 and GCS16H units
(GCS16R excepted). Sensors continuously monitor
air conditions and adjust dampers accordingly. Infi
nite number of damper positions.
2- D8 - Three Position Economizer
Horizontal or Downflow Three Position Economizer.
Optional field installed in all GCS16 and GCS16H
units (GCS16R excepted). Sensors continuously
monitor air conditions and adjust dampers to one of
three positions: closed, mid (minimum) or full open.
NOTE - Even though horizontal and downflow econo
mizers are physically different, they are electrically
identical and therefore, share the same wiring diagram
and D" number.
NOTE - D5 and D8 economizers require night relay
(K11) if night setback is desired with electromechanical
thermostat or W973 control system. Field wiring is
shown in the economizer section of this manual.
3- WarmUp Kit
Warmup kit is shown in Figure 84. Warmup kit is an
accessory to economizer (D5 or D8). The kit provides
warmup capabilities by holding outdoor air dampers
closed during the first heating period after night set
back. When first heating demand is satisfied, warm
up kit allows outdoor air dampers to open to minimum
postion.
Warmup kit does not have its own wiring diagram. It
is included in the C2, C4, C6 and C14 wiring dia
grams.
FIGURE 83
GCS16 UNIT
HORIZONTAL
RETURN AIR
OPENING
SUPPLY AIR OPENING
COMMERCIAL CONTROLS
ENCLOSURE
BLOWER
GCS16-410/510/650
COMMERCIAL CONTROLS HARNESS
J16/P16
FOR CONNECTION OF
CONTROLS
J3/P3
FOR CONNECTION
OF RELAY KITS
DOWNFLOW
RETURN AIR
OPENING