Fan Operation - Single Fan Set Point And Minimum Variables; Defined Modes - Greenheck Vektor Installation, Operation And Maintenance Manual

General Electrical Controls Information
Fan Operation - Single Fan
Set point and minimum variables
1. System will maintain a minimum of 3000 fpm velocity
(factory default) at the outlet of the fan, based on
the airflow monitoring station. Building Management
System (BMS) to monitor nozzle actuator feedback
and keep fan speed above the minimum required set
point to maintain velocity.
2. Fan to run at BMS defined operation for speed and
bypass mode. Mode reference will be determined by
minimum fan speed and by minimum nozzle actuator
feedback.
a. If the BMS speed is equal to the minimum specific
fan speed and nozzle feedback is minimum for a
set time period (user-defined) the BMS will begin to
modulate the bypass damper open to assist with
pressure control.
b. If the bypass damper is at full closed for a set time
period, the BMS will increase fan speed and the fan
control will increase the nozzle area as required to
assist with pressure control.
c. The PID sequence to be programmed at the BMS
for bypass damper operation. The BMS to provide
fan enable and VFD speed reference.
Definition of typical operation modes:
Mode #1: Unoccupied. Defined as no one inside the
lab(s), all lab hoods are closed.
1. Fan will operate at BMS required speed and nozzle
will modulate as necessary to achieve the required
velocity out the fan. BMS to monitor nozzle actuator
feedback and keep fan speed above the minimum
required to maintain velocity.
2. Sure-Aire will measure airflow of the fan. VFD or the
nozzle controller will report this value to BMS.
3. Duct pressure control, by the BMS, will modulate
bypass damper as required if system speed is equal
to the minimum fan speed and nozzle actuator is at
minimum for a time period.
4. VFD speed, duct pressure control and bypass
damper operation is provided by the BMS system.
Mode #2: Occupied; no lab hoods being used.
Defined as people entering the lab(s), no work being
done at the hoods.
1. Fan will operate at BMS required speed and nozzle
will modulate as necessary to achieve the required
velocity out the fan. BMS to monitor nozzle actuator
feedback and keep fan speed above the minimum
required to maintain velocity.
2. Sure-Aire will measure airflow of the fan. VFD or the
nozzle controller will report this value to BMS.
3. Duct pressure control, by the BMS, will modulate
bypass damper as required if system speed is equal
to the minimum fan speed and nozzle actuator is at
minimum for a time period (user-defined).
4. VFD speed, duct pressure control and bypass
damper operation is provided by the BMS system.
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VGN Technology
Mode #3: Occupied; some or all lab hoods being
used. Defined as people in the lab(s), lab hood sashes
being used.
A. Sashes opening in the lab
1. Fan will operate at BMS required speed and nozzle
will modulate as necessary to achieve the required
velocity out the fan. Typical system response
should be to increase fan speed and increase
nozzle open area.
2. Sure-Aire will measure airflow of the fan. VFD or the
nozzle controller will report this value to BMS.
3. VFD speed, duct pressure control and bypass
damper operation is provided by the BMS system.
B. Sashes closing in the lab
1. Fan will operate at BMS required speed and nozzle
will modulate as necessary to achieve the required
velocity out the fan. Typical system response
should be to decrease fan speed and decrease
nozzle open area.
2. Sure-Aire will measure airflow of the fan. VFD or the
nozzle controller will report this value to BMS.
3. Duct pressure control, by the BMS, will modulate
bypass damper as required if system speed
is equal to the minimum fan speed and nozzle
actuator is at minimum for a time period (user-
defined).
4. VFD speed, duct pressure control and bypass
damper operation is provided by the BMS system.
Mode #4: Fault mode. Defined as safety mode;
the system has an issue and needs to default to VFD
bypass.
1. VFD failure detected, automatically or manually put
into VFD bypass if available, by operator or BMS.
2. Nozzle area to increase proportional to fan airflow
which will increase as fan speed is at maximum.
3. Sure-Aire will measure airflow of the fan. VFD or the
nozzle controller will report this value to BMS.
4. Duct pressure control will modulate bypass damper
as required if system is in alarm mode. Duct pressure
control is provided and programmed by the BMS
system.
5. System manually to be reset and placed back in VFD
auto mode.
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