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MERLIN NX IP AND MST/TP VAV CONTROLLER - INSTALLATION INSTRUCTIONS
a. Manually open the damper fully (rotate clockwise).
b. The actuator is shipped with the mechanical end limits
set at 95 degrees. Adjust the two mechanical end-limit
set screws to provide the desired amount of rotation.
Adjust the two set screws closer together to reduce the
rotation travel.
c. Tighten the two mechanical end-limit screws (Phillips #2
screwdriver; (26.5-31 lb.-in. [3.0-3.5 Nm] torque).
d. Using the Declutch button, rotate the universal shaft
adapter fully clockwise.
e. Mount the actuator to the VAV damper box and shaft.
f.
Tighten the two bolts on the centering clamp (8 mm
wrench; 70 lb. in. [8-10 Nm] torque).
g. When the actuator closes, the damper rotates CCW
either 45 or 60 degrees to fully close.
3. If the damper rotates counterclockwise (CCW) to open,
and the angle of the damper open-to-closed is 90
degrees:
a. Manually open the damper fully (rotate counterclock-
wise).
b. Using the Declutch button, rotate the universal shaft
adapter fully counterclockwise.
c. Mount the actuator to the damper box and shaft.
d. Tighten the two bolts on the centering clamp (8 mm
wrench; 70 lb.-in. [8Nm] torque). When the actuator
closes, the damper rotates CW 90 degrees to fully close.
4. If the damper rotates counterclockwise (CCW) to open,
and the angle of the damper open-to-closed is 45 or 60
degrees:
a. Manually open the damper fully (rotate counterclock-
wise).
b. The actuator is shipped with the mechanical end limits
set at 95 degrees. Adjust the two mechanical end-limit
set screws to provide the desired amount of rotation.
Adjust the two set screws closer together to reduce the
rotation travel.
c. Tighten the two mechanical end-limit screws (Phillips #2
screwdriver; (26.5-31 lb.-in. [3.0-3.5 Nm] torque).
d. Using the Declutch button, rotate the universal shaft
adapter fully counter-clockwise.
e. Mount the actuator to the VAV damper box and shaft.
f.
Tighten the two bolts on the centering clamp (8 mm
wrench; 70 lb.-in. [8Nm] torque).
g. When the actuator closes, the damper rotates CW either
45 or 60 degrees to fully close.
Differential Pressure Sensor
Connect the air flow pickup to the two restrictor ports on the
controller.
NOTE:
Use 1/4 in. (6 mm Outside diameter and 5 mm inner
diameter), with a 3/64 in. (1 mm) wall thickness, ple-
num-rated 1219 FR (94V-2) tubing.
Always use a fresh cut on the end of the tubing that
connects to the air flow pickups and the restrictor
ports on the controller. Secure the connection using a
zip tie (procured locally).
EN1Z-1076GE51 R1021
NOTE:
The pressure sensor is polarity sensitive. Connect
the high pressure or upstream tube to the plastic
restrictor port labeled (+), and the low pressure or
downstream tube to the restrictor port labeled (-).
When twin tubing is used from the pickup, split the pickup
tubing a short length to accommodate the connections.
Fig. 9. Airflow pickup connections
Best Practice for Zero Calibration of Air Flow
Sensor
NOTE: The controller must be powered up for a minimum
of 1 hour before performing the zero calibration for
the air flow sensor.
If controllers are mounted in unusually dusty or
dirty environments, an in-line, 5-micron disposable
air filter (use 5-micron filters compatible with pneu-
matic controls) is recommended for the high-pres-
sure line connected to the air flow pickup.
The tubing from the air flow pickup to the controller
should not exceed three feet (1 m). Any length
greater than this will degrade the flow sensing
accuracy.
Use caution when removing tubing from a connec-
tor. Always pull straight away from the connector or
use diagonal cutters to cut the edge of the tubing
attached to the connector. Never remove by pulling
at an angle.
10
Air, N2 , O2
±500 Pa
non-condensing
(± 2" H2O)
0°C
50°C
(32°F)
(122°F)
ø5.2mm
ø3.5mm
Secure with
cable tie
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