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Use the table below to determine which zone dampers to use.
Maximum Differential Pressure refers to the maximum static pressure drop in inches of water column
between the input (upstream) of the zone damper and the output (downstream) when the damper is
closed.
MEDIUM PRESSURE (STMPD Series)
LOW PRESSURE (TR Series)
SYSTEM SIZE
5 TONS OR UNDER
UNDER 7.5 TONS
7.5 TONS OF LARGER
MAXIMUM
DIFFERENTIAL
PRESSURE
0.5"
1"
1.75"
ROUND
DAMPER
LOW PRESSURE
MEDIUM PRESSURE
MEDIUM PRESSURE
RECTANGULAR
DAMPER
LOW PRESSURE
MEDIUM PRESSURE
HEAVY DUTY
ZONE DAMPERS
ROUND ZONE DAMPERS
There are two styles of round zone dampers, low pressure or medium pressure. For systems 5 tons or under with a
maximum differential static pressure of 0.5”, use low pressure dampers. Otherwise use medium pressure for up to
1.75” differential pressure on any system over 5 tons.
ROUND LOW PRESSURE ZONE DAMPERS (TR Series)
Zonex Systems round low pressure zone 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 for very
simple operation. Round damper sizes 9 inches and under are manu-
factured from 24 gauge steel. Sizes 10”, 12”, 14” and 16” are made from
20-22 gauge steel. 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 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 blade shaft without a coupling or set screws, allowing for
a quick and easy motor change if required. Motor drive time from full
open to full close in 30 seconds. 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 dampers 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.
ROUND MEDIUM PRESSURE ZONE DAMPERS (STMPD Series)
The Zonex Systems round medium pressure zone dampers are recom-
mended for any size system above 5 tons, 2000 CFM, and are rated for
a maximum of 1.75” SP. These dampers are constructed from 20-22
gauge galvanized steel, with an elliptical damper disc. The damper
shell is manufactured with the supply end crimped and an air flow
direction arrow. The damper is driven by a 24-volt open / power close,
direct coupled actuator rated at 2VA. The actuator assembly includes
manual open and close stop adjustments and mechanical drive release.
The actuator is designed for full stall operation in the open and close
positions and requires no end switches.
