Brooks Instrument 5866M - Manual (Page 25)

Brooks Instrument Model 5866 Pressure Controller
5-2
3. Observe the output signal and, if necessary, perform the zero
adjustment procedure, Section 6.
4. If the output signal will not zero properly, troubleshoot the sensor using
the procedures given in Section 5-2B. If the sensor is electrically
functional, the printed circuit board is defective and will require
replacement.
5. Connect the controller to a source of the gas it is calibrated for.
Command 100% pressure and adjust the inlet and outlet pressures to
the calibration conditions. Verify that the output signal reaches and
stabilizes at 5.00 Volts.
6. Vary the command voltage over the 5 to 100% range and verify the
output signal follows the set-point.
B. Transducer Troubleshooting (Table 5-2)
1. Troubleshoot the transducer using the steps given in Table 5-2. If any of
the steps do not give the expected result, the transducer assembly is
defective and must be replaced.
2. If the transducer is defective, refer to Sections 5-3 and 5-4 for the
disassembly and assembly procedures for replacing the transducer.
Note: Do not attempt to disassemble the transducer.
5-3 Disassembly
The Model 5866 pressure controller may be disassembled in the field by
the user for cleaning, re-ranging or servicing. The disassembly procedures
below detail the upstream control version of the Model 5866 with a
Normally Closed control valve. The procedures for the upstream control
version and the Normally Open control valve are substantially the same.
Disassemble the controller as follows:
Note: The controller should be disassembled in a clean environment to
prevent contamination.
Do not attempt to disassemble the controller until pressure has
been removed and purging has been performed.
CAUTION
A. Disassembly Procedure [numbers in ( ) refer to Figure 7-1]
1. Remove the jam nut (1) on top of the valve assembly.
2. Unplug the valve connector from the electronics cover and remove the
coil assembly (2).
3. Remove the hex socket screws (3) securing the valve retaining plate (4)
attaching the valve stem assembly (6).
When performing the following procedure, the valve stem must be
removed without cocking it to prevent damage to the valve spring.
CAUTION
4. Carefully remove the valve stem assembly (6).
5. Remove the plunger assembly (7, 8, 9 and 11).
6. Remove and note the position of the valve spring spacers (10). Spacers
may be used above and/or below the lower valve springs (8).
7. Unscrew the orifice (12) from the flow controller body (25).