Brooks Instrument 5851i - Manual (Page 32)

4-4
Installation and Operation Manual
X-TMF-5851i-MFC-eng
Part Number: 541B109AAG
September, 2009
Brooks ® Model 5851 i
Section 4 Maintenance
& Troubleshooting
Table 4-1 lists possible malfunctions which may be encountered during
bench troubleshooting.
C. Sensor Troubleshooting
The sensor tube is part of a calibrated flow divider that is designed to
operate within a preset gas flow range. The sensor assembly may be
removed or replaced by referring to Section 4-4, Disassembly and
Assembly. If the sensor assembly is cleaned and reinstalled, a calibration
check should be performed. Refer to Section 3-4.
NOTE: Do not attempt to disassemble the sensor.
D. Cleaning Procedures
Should the Model 5851 i Mass Flow Controller require cleaning due to
deposition, use the following procedures:
1. Remove the unit from the system.
2. Refer to Section 4-4 to disassemble the controller.
3. Use a hemostat or tweezers to push a 0.007" diameter piano wire
through the flow sensor tube to remove any contamination. For best
results, push the wire into the downstream opening of the sensor tube
(end closest to the control valve). The sensor tube can be flushed with
a non-residuous solvent or DI water. A hypodermic needle filled with
solvent is a convenient means to accomplish this.
Figure 4-1 Torque Sequence for the Valve Retainer Plate