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MAN0585.P65
Issue 01 - 11/99
2987M5023
6. CALIBRATING THE MINIGAS MK5
6.3.3
Purging the Gas Connections
Before calibrating the explosive or toxic gas channels, the gas
connections (Figure 4) must be thoroughly purged with the test
gas or gas mixture.
(1)
Connect the gas cylinder to the calibration hood using
the shortest possible length of tubing, but do not fit the
calibration hood to the instrument under test.
(2)
Turn on the gas cylinder, ensuring that the flow regulator
is set to 300ml/min or, for chlorine, 500ml/min.
(3)
For all gases except chlorine and sulphur dioxide, allow
the test gas to purge the tubing and connections for two
minutes. For chlorine and sulphur dioxide, purge for 10
minutes although a longer purge time may be necessary
if the PTFE connecting tubing is more than about 150mm
(6in.) in length.
(4)
Turn off the gas cylinder.
6.4
CALIBRATION PROCEDURES
6.4.1
General
The following procedures include instructions to apply short,
medium or long duration presses on the internal calibration
button. In this context, short is for a single bleep, medium is for
two bleeps and long is for three bleeps.
Some of the prompt screens appearing on the Minigas Mk5
display during calibration present the operator with a yes/no
option (-y or n-). Press the I/O button for ‘Yes’ or the
O
button for ‘No’.
