Brooks Instrument QMBM - Manual (Page 44)

Section 4 Maintenance
4-4
Installation and Operation Manual
X-CM-QmB-eng
Part Number: 541B029AAG
June, 2011
QmB Series IP40, IP66, IP66XP
Observation Cause Resolution
No Flow or unable to
achieve full flow
If the device has an external
control valve you can replace or
disassemble and clean the valve.
(See Section 4-3)
Particulates in the flow stream. Use an inlet filter.
Agglomeration of fluid at orifice. Consider a larger orifice (valve
stability could suffer).
Chemical deposits. Institute regular PM back flushing.
Poor filtration of process fluid. Install proper filtration.
Valve out of adjustment Contact Brooks Instrument.
(applicable to Controller).
Valve out of adjustment Valve guide spring failure Contact Brooks Instrument.
(applicable to Controller).
Valve override input is grounded Check the valve override input
(Pin12).
Defective electronic board Contact Brooks Instrument.
Output signal follows Setpoint Control valve leaks or is stuck Exercise the control valve
at higher Setpoints but not open. alternating between valve override
at lower Setpoints "open" and closed. If problem
persists backflush the device with
a solvent or purge gas with valve
override "open".
If the device has an external
control valve you can replace or
disassemble and clean the valve.
(See Section 4-3)
Output signal stays in approx. Valve leaks or is stuck open Backflush the device with
5.5 Vdc or 22 mA (applicable to Controller). a solvent or purge gas with valve
(regardless of setpoint) and override "open".
there is flow trough the If the device has an external
meter/controller control valve you can replace or
disassemble and clean the valve.
(See Section 4-3)
+15 Vdc applied to the valve Check the valve override terminal
overrride input (Pin 12).
(applicable to Controller).
Defective PC board. Contact Brooks Instrument.
Table 4-1 Troubleshooting (continued)