4-3
Brooks
®
Model 5850i
Section 4 Maintenance
Installation and Operation Manual
X-TMF-5850i-MFC-eng
Part Number: 541B108AAG
November, 2008
Sensor Troubleshooting
If it is believed the sensor coils are either open or shorted, troubleshoot
using Table 4-2. If any of the steps do not produce the expected results,
the sensor assembly is defective and must be replaced. Refer to Section
4-4 for the disassembly and assembly procedures to use when replacing
the sensor.
NOTE
:
Do not attempt to disassemble the sensor.
Cleaning Procedures
Should the Model 5850
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 (Freon TF** 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.
Figure 4-1 Torque Sequence for the Valve Retainer Plate
