Nailor 37S Manual page 50

FAN POWERED TERMINAL UNITS
Recommended Primary Valve Airflow Ranges For All Fan Powered Terminal Units
The recommended airflow ranges below are for fan powered
terminal units with pressure independent controls and are presented
as ranges for total and controller specific minimum and maximum
airflow. Airflow ranges are based upon maintaining reasonable
sound levels and controller limits using Nailor's Diamond Flow
Sensor as the airflow measuring device. For a given unit size, the
minimum, auxiliary and the maximum flow setting must be within the
range limits to ensure pressure independent operation, accuracy
and repeatability.
Minimum airflow limits are based upon .02" w.g. (5 Pa) differential
pressure signal from Diamond Flow Sensor on analog/digital
controls and .03" (7.5) for pneumatic controllers. This is a realistic
low limit for many transducers used in the digital controls industry.
Check your controls supplier for minimum limits. Setting airflow
minimums lower, may cause hunting and failure to meet minimum
ventilation requirements.
Imperial Units, Cubic Feet per Minute
Metric Units, Liters per Second
The high end of the tabulated Total Airflow Range on pneumatic
and analog electronic controls represents the Diamond Flow
Sensor's differential pressure reading at 1" w.g. (249 Pa). The high
end airflow range for digital controls is represented by the indicated
transducer differential pressure.
ASHRAE 130 "Performance Rating of Air Terminals" is the method
of test for the certification program. The "standard rating condition"
(certification rating point) airflow volumes for each terminal unit size
are tabulated below per AHRI Standard 880. These air volumes
equate to an approximate inlet velocity of 2000 fpm (10.2 m/s).
When digital or other controls are mounted by Nailor, but supplied
by others, these values are guidelines only, based upon experience
with the majority of controls currently available. Controls supplied
by others for factory mounting are configured and calibrated in the
field. Airflow settings on pneumatic and analog controls supplied by
Nailor are factory preset when provided.
C
C13