Omega FMA1700A User Manual page 25

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
FMA1700A/1800A.
Gas flows through the
FMA1700A/1800A, but LCD
Display reading and output
voltage 0-5 Vdc signal do
not responds on the flow.
Gas does not flow through
the FMA1700A/1800A 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
FMA1700A/1800A, 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
FMA1700A/1800A, but LCD
Display reading is negative
and does not change
according to gas flow.
Output voltage
0-5 Vdc signal corresponds
correct gas flow.
LIKELY REASON
Sensor under swamping
conditions (flow is more
than 10% above maximum
flow rate for particular
FMA1700A/1800A).
PC board is defective.
The gas flow is too low for
particular model of
FMA1700A/1800A.
FMA1700A/1800A Series
Max Flow 10 L/min 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.
FMA1700A/1800A is
installed in the installation
with back pressure
conditions and gas leak
exist in the system.
5.00 Vdc reference voltage
(green wire) is
disconnected inside of the
LCD Display.
21
REMEDY
Lower the flow through
FMA1700A/1800A within
calibrated range or shut
down the flow completely.
The swamping condition will
end automatically.
Return FMA1700A/1800A 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 12). NOTE: Calibration
accuracy can be affected.
Return FMA1700A/1800A to
factory for repair.
Flush clean or disassemble
to remove impediments or
replace the filter screen
(see 6.2 on page 11).
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
FMA1700A/1800A has
internal leak return it to
factory for repair.
Carefully remove the LCD
from FMA1700A/1800A.
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 connection.