Brooks Instrument GF81 - Manual (Page 43)

4-5
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
Symptoms & Possible Causes Corrective Action
2. Flow out of range (Continuted).
Is the device zero correct? Zero the device according to zeroing
procedure in Section 2-16. Verify leak check rates
are OK.
3. No gas control; flow is at or
above maximum.
Is the gas pressure across the device Verify that the pressure is correct for the gas and
too high? range. If required, adjust inlet/outlet pressure to
achieve proper pressure reading.
Are system valves open, or is the Use tool software to verify.
purge input activated? Confirm that pin 12 is not connected to an active voltage
source.
Is the setpoint correct for the Use tool software to verify.
required flow?
4. No gas flow above some setpoint.
NOTE: When the setpoint is
increased beyond this point,
the
GF40/GF80/GF81 Series signal remains at
some value lower than the set-point.
Is the gas inlet/outlet differential Verify that the pressure is correct for
pressure sufficient? the gas and range. If required, adjust
regulator to achieve proper pressure.
NOTE: If the pressure is too low,
the valve voltage to the
GF40/GF80/GF81 Series
will be at its maximum output. This condition
will cause internal GF valve heating and
inability to properly reach desired flow setpoints.
Is the GF40/GF80/GF81 Series calibrated for the Check GF40/GF80/GF81 Series side label. Run a flow check
gas flow? to verify. If flow is incorrect, replace the GF40/GF80/GF81
Series with a unit that is calibrated properly.
Table 4-2 GF40/GF80/GF81 Series Troubleshooting Guide (Continued)