Heath Consultants Gasurveyor 500 Series - Manual (Page 54)

GASURVEYOR 3-500 USER HANDBOOK
B-6
4) Turn the regulator valve counter clockwise to open
the valve slightly. Make sure that the gas is flowing
before connecting the sample tubing to the
instrument, otherwise an instrument sample fault
may occur.
5) Connect tubing from regulator to instrument inlet
then adjust the regulator valve to maintain a
constant flow of gas (counter clockwise to increase
flow and clockwise to decrease). The correct flow
rate is achieved when the ball in the indicator tube
floats just above its resting position.
6) Wait for the instrument gas reading to settle.
7) If the displayed reading corresponds to the
concentration of calibration gas, i.e. 50% LEL
(2.5% Methane in Air), proceed to paragraph 10.
8) If the displayed reading does not correspond to
the concentration of calibration gas, i.e. 50% LEL
(2.5% Methane in Air), press and hold Button One
to enter SPAN mode.
SPAN mode is indicated by the selected range, in
this case LEL, and SPN alternating in the display
as shown in Figure B-6.
Figure B-6 SPAN Mode Display