Aalborg GFM - Manual (Page 24)

20
INDICATION
LCD Display reading is
above maximum flow range
and output voltage 0-5 Vdc
signal is more than 5.5 Vdc
when gas flows through the
GFM.
Gas flows through the GFM,
but LCD Display reading
and output voltage 0-5 Vdc
signal do not responds on
the flow.
Gas does not flow through
the GFM with inlet pressure
applied to the inlet fitting.
LCD Display reading and
output voltage 0-5 Vdc
signal show zero flow.
Gas flows through the GFM,
but LCD Display reading
is negative and output
voltage 0-5 Vdc signal do
not responds on the flow
(reading near 10mV).
Gas flows through the GFM,
but LCD Display reading is
negative and does not
change according to gas
flow. Output voltage
0-5 Vdc signal corresponds
correct gas flow.
REMEDY
Lower the flow through GFM
within calibrated range or
shut down the flow com-
pletely. The swamping con-
dition will end automatically.
Return GFM to factory for
repair.
Check maximum flow range
on transducer's front panel
and make required flow
adjustment.
Unscrew the inlet compres-
sion fitting of the meter and
reinstall RFE (see 6.2.2 on
page 11). NOTE: Calibration
accuracy can be affected.
Return GFM to factory for
repair.
Flush clean or disassemble
to remove impediments or
replace the filter screen
(see 6.2 on page 10).
NOTE: Calibration accuracy
can be affected.
Check the direction of gas
flow as indicated by the
arrow on the front of the
meter and make required
reconnection in the installation.
Locate and correct gas leak
in the system. If GFM has
internal leak return it to
factory for repair.
Carefully remove the LCD
from GFM. Remove the
aluminum housing on the
side of the connection cable.
Side the LCD assembly out
of the aluminum housing.
Check connection for green
wire (5.00 Vdc reference
voltage). If any wire is
disconnected restore con-
nection.
LIKELY REASON
Sensor under swamping
conditions (flow is more
than 10% above maximum
flow rate for particular
GFM).
PC board is defective.
The gas flow is too low for
particular model of GFM.
GFM17 models: RFE is not
connected properly to the
inlet fitting.
Sensor or PC board is
defective.
Filter screen obstructed at
inlet.
Direction of the gas flow is
reversed.
GFM is installed in the
installation with back pres-
sure conditions and gas leak
exist in the system.
5.00 Vdc reference voltage
(green wire) is disconnected
inside of the LCD Display.