17
3 WIRE ZONE DAMPERS
Zonex Systems zone dampers are
used in cooling/heating systems to
provide room by room zone
control. The damper is provided
with a factory mounted actuator.
Each zone damper is controlled
by a zone thermostat. More than
one damper can be controlled by
one zone thermostat. Use this
table to determine which zone
dampers to use.
ROUND MEDIUM PRESSURE ZONE DAMPERS
ROUND MEDIUM PRESSURE DAMPER
PART NUMBERS AND SIZES
TYPICAL ROUND CAPACITIES
These air quantities were derived from a duct sizing
chart 0.1” friction loss per 100’ of duct. All CFMs
listed are approximate. For accurate selection, use
duct sizing table or device.
DAMPER MODEL
MAXIMUM
DIFFERENTIAL
PRESSURE
MAXIMUM
SYSTEM SIZE
MAXIMUM
DUCT SIZE
STMRX
Round Med. Pressure
1.75”
Any Size
18”
STCRX
Rect. Heavy Duty
1.75”
Any Size
48”W x 48”H
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.
DUCT
DIAMETER
NOMINAL
CFM
DUCT VELOCITY
FPM
DAMPER
∆
P “ WC
6”
110
540
.014
8”
250
700
.015
10”
410
750
.015
12”
660
850
.022
14”
1000
925
.035
16”
1450
1070
.036
18”
2000
1100
.036
L
W
D
ROUND DIMENSIONAL DATA
PART #
SIZE
D
L
W
STMRX06
6
6”
10”
9”
STMRX08
8
8”
10”
11”
STMRX10
10
10”
12”
13”
STMRX12
12
12”
14”
15”
STMRX14
14
14”
16”
17”
STMRX16
16
16”
18”
19”
STMRX18
18
18”
23”
21”
MEDIUM PRESSURE (STMRX)
Zonex Systems round medium pressure zone dampers are recom-
mended for systems with a maximum differantial static pressure up to
1.75”. This power open / power closed damper is manufactured from
20-22 gauge galvanized steel with rolled-in stiffening beads for superior
rigidity. Mechanical minimum and maximum set stops are provided and
are easily adjustable. Do not install damper in an inverted position. A
hat section supports a reversing 24vac, 60Hz, 2 VA motor. Motor drive
time from full open to full close is 90 seconds.
