Honeywell S7751A Product Data page 25

Maximum
From the BALANCE VAV Main Menu, the operator would select the Maximum menu item and then press the Enter key. The
HHT attempts to drive the box flow to the maximum setpoint. While the HHT is driving the control to maximum flow, the
operator is prevented from entering a value until the air flow has stabilized. The following screen display instructs the operator
to Please Wait until Stabilizing is complete
M A X I M U M
Stabilizing,
Please Wait
If the air flow does not stabilize, an error message appears: Unable to Calibrate, Air flow Unstable and the speaker beeps
and the following screen displays.
M A X I M U M
Unable to Calibrate,
Air Flow 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 A X I M U M
Max Setpt <setpt>
Current CFM <cfm>
Measured CFM <cfm>
Once the air flow is stable, the display shows the operator the Max Setpt and 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 Minimum first . The operator must calibrate the minimum flow point first and then calibrate the
maximum.
Minimum
From the BALANCE VAV Main Menu, the operator would select the Minimum menu item and then press the Enter key. The
HHT attempts to drive the box flow to the minimum setpoint. While the HHT is driving the control to minimum flow, the
operator is prevented from entering a value until the air flow has stabilized The following screen display instructs the operator
to Please Wait until Stabilizing is complete.
M I N I M U M
Stabilizing,
Please Wait
If the air flow does not stabilize, an error message appears: Unable to Calibrate, Air flow Unstable the speaker beeps and
displays the following screen.
Page 25
EXCEL 10 HAND HELD TOOL
74-2566