Brooks – Brooks Instrument GF81 User Manual
Page 42
4-4
Brooks
®
GF40/GF80/GF81 Devices
Installation and Operation Manual
X-TMF-GF40-GF80-Series-MFC-eng
Part Number: 541B161AAG
June, 2013
Section 4 Maintenance & Troubleshooting
4-5 GF40/GF80/GF81 Series Troubleshooting Guide
Symptoms & Possible Causes
Corrective Action
1. No gas flow.
Is the gas supply turned on?
Check shut-off valve and pressure readout. Open
the gas supply.
Is the regulator turned on at the
Turn off the regulator and reset it to the
correct operating pressure?
recommended pressure as described in the
Data Sheet.
Are any upstream or downstream
Verify that the valves are open and operating
shut-off valves closed, either by
properly.
the system or because of failure?
Is the MOD LED light on the
GF40/GF80/GF81
Observe the LED display panel on top of the GF40/GF80/
Series lit solid green?
GF81device to verify. If the LED light is not lit, cycle power
to reboot the device.
Is the commanded setpoint from
Use the tool software to verify.
tool/system at 0.00 Vdc?
Has the valve been commanded
Use the tool software to verify.
off by an active “valve closed” input?
Confirm that pin 12 is not connected to DC common.
2. Flow out of range.
Is the gas inlet/outlet pressure differential
Verify that the pressure is correct for the gas
either too high or too low?
and range. If required, adjust inlet/outlet pressure
to achieve proper pressure reading.
NOTE: If the differential pressure is too high,
voltage to the valve will be zero, which is
abnormally low for the setpoint. If the
differential is too low, voltage to the valve will
be at its maximum value, which is abnormally
high for the set-point.
Is the MOD LED light on the GF40/GF80/Gf81
Observe the LED at the top of the GF40/GF80/GF81 device.
Series lit solid green?
If the LED light is not lit, cycle power the device to
reboot.
Is the setpoint correct for the
Use the tool software to verify the analog signal.
required gas flow?
Is the device calibrated for the
Check the device side label. Run a
particular gas?
flow check to verify.
Table 4-2 GF40/GF80/GF81 Series Troubleshooting Guide