Brooks Instrument 5851i - Manual (Page 30)

4-2
Installation and Operation Manual
X-TMF-5851i-MFC-eng
Part Number: 541B109AAG
September, 2009
Brooks ® Model 5851 i
Section 4 Maintenance
& Troubleshooting
A. System Checks
The 5851 i is generally used as a component in gas handling systems
which can be quite complex. This can make the task of isolating a
malfunction in the system a difficult one. An incorrectly diagnosed
malfunction can cause many hours of unnecessary downtime. If possible,
make the following system checks before removing a suspected defective
mass flow controller for bench troubleshooting or return, especially if the
system is new:
1. Verify low resistance power supply connections and that the correct
power supply voltage and signals are reaching and leaving the
controller. The breakout board (P/N S273Z668AAA) listed in Section
5 will make this job much easier.
2. Verify that the process gas connections have been correctly
terminated and leak checked.
3. If the mass flow controller appears to be functioning but cannot
achieve setpoint, verify that sufficient inlet pressure and pressure
drop are available at the controller to provide the required flow.
4. Verify that all user selectable jumpers are in their desired positions.
Refer to Figure 3-3.