Honeywell S7751A Product Data page 26

EXCEL 10 HAND HELD TOOL
M I N I M U M
Unable to Calibrate,
Airflow Unstable
If the air flow has stabilized (stabilization occurs when the air flow value is within a preprogrammed hysteresis of the setpoint
for at least five seconds or three readings, whichever is greater), the speaker beeps and displays the following screen.
M I N I M U M
Min Setpt <setpt>
Current CFM <cfm>
Measured CFM <cfm>
Once the air flow is stable, the display shows the operator the Min Setpt , the Current or Measured CFM (continuously
updating) and a space for the operator to enter a measured flow value (measured by a flow hood). After the operator presses
the Enter key, the HHT loads the new value into the controller and then updates the Current CFM and removes the
Measured CFM from the display. The Current CFM value remains on the display until it is edited or until the Prev Menu key
is pressed. If the result would make a negative curve (such as MAX is less than MIN) the HHT prevents the operation and
displays Error, Calibrate Maximum first . The operator must calibrate the maximum flow point first and then calibrate the
minimum.
Full Open
From the BALANCE VAV Main Menu, the operator would select the Full Open menu item and then press the Enter key and
the following screen displays.
F U L L O P E N
O p e n i ng D a m p e r
Please Wait
The HHT commands the Excel 10 controller damper to the fully open position and waits an additional 50.0% of the motor
drive time to assure that the box is fully open as the following screen displays.
F U L L O P E N
Current CFM <cfm>
Overdriving
Please Wait
The HHT displays the Current CFM and updates continuously to show the maximum amount of air flow available. This
command is useful to see how close the system can come to the maximum setpoint. The operator has to press the Prev
Menu key to go back to the BALANCE VAV Main Menu.
Defaults
From the BALANCE VAV Main Menu, the operator can select the Defaults menu item and then press the Enter key. The
HHT reads the factory defaults from the HHT's ROM and downloads them into the controller in the event that the operator has
failed to follow instructions or electrical noise spikes have corrupted the data in the controller.
NOTES: Once the operator has zeroed a controller, it is not necessary to redo the Maximum and Minimum adjustments if the
controller is re-zeroed. Software knows where the Maximum and Minimum values should be, based on the last zero
value.
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