COMPACT VAV CONTROLLER WEB-VA423B24N – INSTALLATION INSTRUCTIONS
Connect the air flow pickup to the two restrictor
ports on the controller.
in. (6 mm) outside diameter, with a
in. (1 mm) wall thickness, plenum-
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.
It is recommended (not compulsory) to 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 (-).
See labeling in Fig. 11. When twin tubing is used
from the pickup, split the pickup tubing a short
length to accommodate the connections.
Fig. 11. Airflow pickup connections
If controllers are mounted in unusually
dusty or dirty environments, an inline, 5-
micron disposable air filter (use 5-micron
filters compatible with pneumatic
controls) is recommended for the high-
pressure line connected to the air flow
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
connector. 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
Best practice for zero calibration of air flow
The controller must be powered up for a minimum
of 1 hour before performing the zero calibration for
the air flow sensor.