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ZONE DAMPERS
RECTANGULAR LOW PRESSURE ZONE DAMPERS (TREC W x H)
Zonex Systems rectangular low pressure dampers can be used for systems up to 5 tons with a
maximum differential static pressure of 0.5”. These are two position, spring open, power close
dampers. They are constructed from heavy duty galvanized steel. The damper is a single blade
type that slips into a 2-1/2” wide cutout in the existing duct and attaches with screws via a duct
mounting plate. The duct mounting plate is 5” wide. The drive assembly supports a synchronous
24V AC 60Hz 12VA motor and terminal board. The motor is designed for continuous full stall
operation. Special winding and heavy duty gearing provide for long motor life and easy spring
open operation. A cross pin on the motor shaft provides positive direct drive to the damper shaft
without a coupling or set screws. A red LED will be illuminated on the damper terminal
board to indicate when the damper is being powered closed. The LED will remain on when the damper
is fully closed and cycle off when the damper is opening or in the full opened position. Since this
is a spring open damper, in the event of power failure the damper fails to the full open position.
LOW PRESSURE (TREC W x H) RECTANGULAR
DAMPER
Zonex Systems zone dampers are used in cooling/heating systems to
provide room by room zone control. The damper is provided with a
zone actuator. Each zone damper is controlled by a zone thermostat.
More than one damper can be controlled by one zone thermostat.
ROUND LOW PRESSURE ZONE DAMPERS (TR diam)
Zonex Systems round low pressure zone dampers can be used for systems up to 5 tons with a max-
imum differential static pressure of 0.5”. These are two position, spring open, power close
dampers for very simple operation. All sizes are designed with rolled-in stiffening beads for
superior rigidity. The damper pipe is furnished with one crimped end and one straight end for
easy installation. A hat section supports a synchronous 24V AC 60Hz 12VA motor and termi-
nal board. The motor is designed for continuous full stall operation. Special winding and heavy
duty gearing provide for long motor life and easy spring open operation. A cross pin on the
motor shaft provides positive direct drive to the damper blade shaft without a coupling or set
screws, allowing for a quick and easy motor change if required. A red LED will be illuminated on
the damper terminal board to indicate when the damper is being powered closed. The LED will
remain on when the damper is fully closed and cycle off when the damper is opening or in the full
opened position. Since this is a spring open damper, in the event of power failure, the damper fails
to the full open position.
LOW PRESSURE (TR diam)
SIZING ZONE DAMPERS
If the ductwork already exists, simply size the damper to fit the ductwork.
For new systems or retrofit jobs:
a) Determine CFM from heat gain or loss calculations.
b) Select damper size by using a duct sizing table or calculator.
c) Select a Zonex Systems damper to fit the duct size selected for that
zone.
DAMPER INSTALLATION NOTES
1. Do not exceed 700 FPM in a register/diffuser branch duct.
2. If a damper is installed within 3 feet of register/diffuser, install sound
attenuating flex duct between damper and outlet.
3. Zone dampers should be preceded by 2’-4’ of straight pipe where
possible.
4. In attic installations and high humidity areas, the Zonex Systems
damper should be insulated along with the ductwork. The hat section
on the damper is delivered with insulation between the hat section
and pipe. Therefore, insulation should be applied to the round pipe
and butted against the hat section (do not insulate the motor or relay
board). Both motor and the relay board generate enough heat so that
no condensation will develop on the hat section.
5. Remember to allow a 16” gap in the duct for Heavy Duty rectangular
dampers.
6. Low and medium pressure rectangular dampers slide into a 3” wide
cutout in the ductwork.
7. Install TR round dampers to the motor in the 9 to 3 o’clock position.
Do not install damper so the motor is in the 4 to 8 o’clock position.
