Operating Instructions

Fume Hood Controller Owner's Manual
14 Siemens Building Technologies, Inc.
The Fume Hood Controller maintains a constant face velocity until the maximum flow
condition occurs. At that point, the controller controls to a constant exhaust volume. In the
maximum flow mode, the face velocity drops below the desired setpoint as the open sash
area increases toward the fully open position. This may cause an alarm condition to occur.
Display Filters
If enabled, the average face velocity is displayed at the ODP. There are two filters associated
with the displayed face velocity.
One filter assigns a time average value to the face velocity. If set to 100%, the value of the
face velocity displayed at the ODP is the same as the average face velocity and may
fluctuate rapidly. When set to a value less than 100%, the displayed value will stabilize and is
most effective if set to a value of 30% or less. Changing this value will not effect the control of
the Fume Hood, it is only for the display.
NOTE: If set to 0%, the ODP will "freeze" at the last read value. A value other than 0%
allows the ODP to update the displayed face velocity.
The second filter is the change of value (COV) limit for face velocity readings. The face
velocity displayed at the ODP will update only if the face velocity has changed by the amount
set.
Calibration
Air Velocity Sensor - Calibration of the controller's air velocity sensor must be performed
during start-up.
Venturi Air Valve – Calibration of the Venturi Air Valve(s) must be performed during start-up
with fully operational supply and general exhaust airflow systems. The supply and general
exhaust Air Velocity Sensors must be calibrated and working normally prior to air valve
calibration.
Warning and Alarm Features
The Fume Hood Controller indicates fume hood performance problems at two levels,
WARNING and ALARM. The two levels are available so different procedures can be
instituted for each condition. Both levels are indicated locally at the ODP and, if connected to
a field panel, centrally through the APOGEE alarm features.
NOTE: Central alarms only work if the field panel is specifically set up to receive and
distribute the alarm information. Consult your local Siemens Building
Technologies, Inc. representative for more information on central alarming.