Specifications

FIGURE 28
OAD24 AIR DAMPER
Page 24
XI-ACCESSORIES
This section describes the application of most of the optional
accessories which can be connected to the GCS24. Some of
the accessories (for example, the Warm Up Control Kit) are
described in the commercial controls section of this manual.
A-RMF16 Mounting Frame
When installing a GCS24 unit on a combustible surface for
downflow discharge applications, the Lennox RMF16 roof
mounting (figure 26) frame is used. Otherwise, the RMF16 is
recommended but not required. The GCS24, if not mounted
on a flat (roof) surface, MUST be supported under all edges
and under the middle of the unit to prevent sagging. The
GCS24 MUST be mounted level within 1/16" per linear foot in
any direction.
FIGURE 26
TYPICAL MOUNTING FRAME
RMF16-135/160 SHOWN
DETAIL A
DETAIL B
SUPPLY
OPENING
RETURN
OPENING
FIGURE 27
UNIT BASE
FIBERGLASS
INSULATION
RIGID
INSULATION (FIELD
FURNISHED)
MOUNTING FRAME
(Extends around
entire perimeter of unit)
NAILER STRIP
COUNTER-FLASHING
(FIELD FURNISHED)
ROOF MATERIAL
CANT STRIP
(FIELD FURNISHED)
BASE RAIL
(1-1/2" X 3")
TYPICAL ROOF CURB FLASHING
The assembled RMF16 mounting frame is shown in figure 26.
Refer to the RMF16 installation instructions for details of prop
er assembly and mounting. The roof mounting frame MUST
be squared to the roof before mounting. Plenum system
MUST be installed before the unit is set on the mounting
frame. Typical roof curbing and flashing is shown in figure 27.
Refer to the RMF16 installation instructions for proper plenum
construction and attachment.
B-OAD24 Outdoor Air Damper
OAD24 is a manual outdoor air damper section (figure 28)
which installs in GCS24 to allow a fixed amount of outside air
into the system. OAD24 consists of a set of manually oper
ated dampers which may be adjusted and locked in place to
allow up to 25 percent outside air into the system at all times.
Automatic operation is available with addition of an electric
springreturn threeposition damper actuator. Refer to OAD24
installation instructions
for specific installation
procedure. Washable fil
ter supplied with the
OAD24 can be cleaned
with water and a mild
detergent. It should be
sprayed with Filter Han
dicoater when dry prior
to reinstallation. Filter
Handicoater is R.P.
Products coating no. 418 and is available as Lennox Part No.
P-8-5069.
C-Economizer
Optional economizer dampers can be applied directly to
GCS24. An economizer consists of a mechanically linked re
circulated air and outdoor air damper assembly, an enthalpy
sensor and damper motor installed in the economizer. An en
thalpy control assembly is also furnished and may be installed
in the filter access area of the unit or in the economizer (de
pending on model). An exhaust damper assembly installed in
the economizer provides return air exhaust.
Several accessories are available and may be used with any
economizer. Optional Warm Up Kit may be added to any
economizer if electromechanical or simple electronic control
thermostat is used with night setback. Warm Up Kit forces
outdoor air dampers closed during initial morning warm up.
Optional GED16 gravity exhaust dampers may be installed
on any economizer to provide automatic pressure relief in re
turn air duct. Optional differential enthalpy control may be
added to any economizer to monitor both indoor and out
door air conditions. With differential enthalpy installed, the
economizer selects the lowest of the two enthalpy condi
tions to satisfy cooling demand.