U S E R M A N U A L
Connect the open end of the gas pipe to the gas tap
or sample point on the pipework to be checked.
Press the ‘start pump’ key on the GFM430
instrument, then open the gas tap to allow the gas to
flow through the instrument. A series of moving
chevrons at the top right-hand corner of the display
screen indicates that the pump is switched on and
gas is flowing through the instrument.
Wait for the
reading to
stabilise, then
press the ‘stop
pump’ key to retain the reading. This will
return the highlight area around the gas
figures.
Gas pressure measurement
Leave the gas pipe connected to the gas tap
and press the Next key to switch to Channel
Group 2 – Pressure, Temperature and
Velocity.
The display screen will change to show the
last retained gas pressure, temperature and
velocity readings indicated by highlights around the figures.
Now press the ‘start sample’ key. The instrument will now measure the pressure or
vacuum in the site pipework.
When the reading has stabilised,
press the ‘stop sample’ key to
retain the reading. This will
return the highlight area around
the pressure figure.
Turn off
the gas tap on the sample point
and remove the gas pipe.
AP = atmospheric pressure
SP = static pressure; +ve =
pressure, -ve = vacuum
14
GFM400 Series User Manual
G F M 4 0 0 S E R I E S
Take great care
when connecting
the pipe to the gas
tap to avoid gas
leakage.
Take great care
when dis-
connecting the
pipe from the gas
tap to avoid gas
leakage.
GFM400 Series
