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Calgary, Canada
Tel: 403-279-8619
Fax: 403-279-5035
Houston, Texas
Tel: 281-590-1172
Fax: 281-590-3086
Las Vegas, Nevada
Tel: 702-648-5400
Fax: 702-638-0400
Toronto, Canada
Tel: 416-744-3300
Fax: 416-744-3360
“ C o m p l e t e A i r C o n t r o l a n d D i s t r i b u t i o n S o l u t i o n s . ”
w w w . n a i l o r . c o m
4/09
IOM-BPTU
Mechanical Minimum Stop Field Setting
Procedure
Pneumatic Actuator
(MCP-3631 Series)
Actuator rotation is 100°. Angle of
rotation can be limited by inserting a
1/4" – 20 stroke stop screw into
front end of actuator and securing
with a lock nut (field supplied by
user). Length of screw is
unimportant as long as it has adequate thread length. Damper
rotates 90°, CW to close and has built in end stops.
1. Direct acting/normally closed damper connection: Disconnect
control air to actuator. Ensure damper and actuator are in
alignment. Damper should be fully closed.
(a) Using mechanical minimum stop. Adjust screw to back-off
damper to required minimum airflow position.
(b) Using damper end stops (no mech. minimum stop provided).
Loosen collar set and bushing on damper shaft. Rotate damper
shaft CCW to desired minimum airflow position and re-tighten
actuator connection.
2. Reverse acting/normally open damper connection:
(a) Using stroke stop screw. Apply 20 psi main air to actuator.
Insert screw (by others) and back-off damper to required minimum
airflow position.
(b) Using damper end stops (no built-in stroke stop screw). Loosen
damper/actuator collar set and bushing coupling. Apply 20 psi main
air to actuator. When actuator reaches the end of its rotation, rotate
damper shaft CCW to desired minimum airflow position and re-
tighten on shaft.
Electric Actuators
KMC MEP-5071 (standard). Position damper to the full open
position. Depress the gear disengagement button and position the
drive collar so the indicator mark is at the "90" mark. Tighten
setscrews on shaft. Loosen lower travel stop one-half turn and slide
to desired position. Tighten stop screw.
Honeywell ML6161B-2024 (optional). Use clutch to position damper
in fully open position. Insert setscrew with lock nut (supplied) in the
threaded hole in top left corner of actuator, turning CW until fully
inserted. With setscrew fully inserted, minimum position is 30°, fully
out O°. Use conversion of approx. 1.7 angular degrees per turn of
the setscrew. Back screw out of housing and stop slightly short of
the calculated position. This allows the setscrew to be set
accurately while taking airflow measurements. (Important: Do not
back-drive actuator with setscrew, damage may result.) Rotate
actuators to minimum position using the manual declutch.
Accurately set minimum flow by backing-off setscrew as required
using airflow measurement. Using locknut, secure against actuator
housing to lock setscrew in place.
Desired
Insertion of
Rotation Stop Screw
95°
0.520" (13.2)
85°
0.700" (17.8)
75°
0.875" (22.2)
65 °
1.050" (26.7)
55°
1.220" (40.0)
45°
1.400" (35.6)
BYPASS
BALANCING DAMPERS
INLET
BALANCING
DAMPER
FLOW
DIVERTER
VALVE
DAMPER ACTUATOR
FIELD ADJUST FOR MINIMUM
AIR VOLUME IF REQUIRED
SUPPLY
AIRFLOW
HI.(Ps)
MAGNEHELIC
GAUGE
OUTLET BALANCING DAMPER
AT TAKE-OFF
DISCHARGE
AIRFLOW
