Accessories - Lennox ZGB Series Unit Information

VII-ACCESSORIES
The accessories section describes the application of most
of the optional accessories which can be factory or field
installed to the ZGB units.
A-Z1CURB
When installing the ZGB units on a combustible surface
for downflow discharge applications, a Z1CURB 8-inch,
14-inch, 18-inch, or 24-inch height roof mounting frame is
used. The roof mounting frames are recommended in all
other applications but not required. If the ZGB units are
not mounted on a flat (roof) surface, they MUST be sup-
ported under all edges and under the middle of the unit to
prevent sagging. The units MUST be mounted level within
1/16" per linear foot or 5mm per meter in any direction.
The assembled mounting frame is shown in figure 21. Re-
fer to the roof mounting frame installation instructions for
details of proper assembly and mounting. The roof mount-
ing frame MUST be squared to the roof and level before
mounting. Plenum system and block-off panels MUST be
installed before the unit is set on the mounting frame. Typ-
ical roof curbing and flashing is shown in figure 22. Re-
fer to the roof mounting frame installation instructions for
proper plenum construction and attachment.
B-Transitions
Supply/return transitions are field-provided.
C-Supply and Return Diffusers (all units)
Optional flush mount diffuser/return FD9-65 and extended
mount diffuser/return RTD9-65 are available foruse with
all ZGB units. Refer to manufacturer's instructions includ-
ed with transition for detailed installation procedures.
ASSEMBLED ROOF MOUNTING FRAME
FIGURE 21
UNIT BASE
BOTTOM
FIBERGLASS
INSULATION
(Furnished)
NAILER STRIP
(Furnished)
RIGID INSULATION
(Field Supplied)
ROOF
MOUNTING FRAME
(Extends around entire
perimeter of unit)
D-Economizer (Field or Factory Installed)
Downflow economizers are a factory-installed option.
Downflow and horizontal air flow economizers are a fac-
tory- or field-installed option. Economizers are equipped
with an A6 enthalpy control, an R1 mixed air sensor and
an S175 outdoor sensible sensor. The modulating econo-
mizer opens fully to use outdoor air for free cooling when
temperature is suitable and opens to minimum position
during the occupied time period.
When A6 determines outdoor air is suitable (via input from
S175 outdoor air sensor), dampers will modulate open
(via B7 damper motor) to maintain 55°F (13°C) supply air
(determined by input from R1 mixed/supply air sensor).
The A6 enthalpy control and B7 damper motor are shown
in figure 23 for downflow air discharge and figure 24 for
horizontal air discharge. The R1 mixed air sensor is shown
in figure 25. An A7 outdoor enthalpy sensor is optional and
replaces the S175 sensible sensor. See figure 26.
ECONOMIZER - DOWNFLOW
B7
DAMPER
MOTOR
A6
ENTHALPY
CONTROL
Page 45
TYPICAL FLASHING DETAIL
UNIT BASE
RAIL
COUNTER FLASHING
(Field Supplied)
CANT STRIP
(Field Supplied)
ROOFING
MATERIAL
FIGURE 22
FIGURE 23