Brooks Instrument 5851E - Manual (Page 36)

4-4
Brooks ® Model 5851E
Section 4 Maintenance Installation and Operation Manual
X-TMF-5851E-MFC-eng
Part Number: 541B104AAG
November, 2008
Table 4-2 Sensor Troubleshooting
Do not ground Terminal 10 when 5 Volt reference output is enabled.
Irreparable damage to the PC Board may result.
CAUTION
3. Use a hemostat or tweezers to push a 0.007" dia. piano wire through
the flow sensor tube to remove any contamination. For best results
push the wire into the downstream end of the sensor tube (end closest
to the control valve). The sensor tube can be flushed with a non-
residuous solvent (Freon TF
TM recommended). A hypodermic needle
filled with solvent is a convenient means to accomplish this.
An alternate method for flushing out the sensor is to replace the
restrictor element with a low flow plug restrictor. This plug forces all the
flow through the sensor and may dislodge any obstructions. With the
valve orifice removed, subject the flow controller to a high differential
pressure. Pressurizing the outlet of the MFC higher than the inlet may
help force the obstruction upstream and out of the sensor tube.