E Instruments E8500 - Chapter 12 Maintenance

E8500 Instruction & Operations Manual version 1.010
Page 36 of 45
Stack Draft Calibration
To obtain a span calibration of the draft sensor, connect a manometer to the end of the
probe through a T fitting. Leave one side of the T open. Restrict the open side of the T
with a suitable plug or valve. In the SPAN MENU, use the UP / DOWN keys to select a
suitable draft calibration span between 5" H
2
O and 10" H
2
O. Press the OK key. The
pump will be on and the display will read:
PRESS OK AT 10”
Very slowly start closing the intake valve of the apparatus and observe the manometer
reading climbing. Set the valve opening as soon as the manometer is reading the same
pressure as that selected on the display. Press the OK key again. The draft sensor will
be calibrated to the value shown on the display.
Velocity Calibration
To obtain a span calibration of the velocity sensor, connect a manometer to the end of
the probe through a T fitting. In the SPAN MENU, use the UP / DOWN keys to select a
suitable velocity calibration between 1.0" H
2
O and 3.0" H
2
O. Press the OK key. The
display will read:
PRESS OK AT 1.0”
Increase the pressure using a pressure source, and observe the manometer reading
climbing. When the manometer is reading the same pressure as that selected on the
display, press the OK key. The velocity sensor will be calibrated to the value shown on
the display.