QmB Series IP40, IP65, IP65XP
Section 4 Maintenance
4-3
Installation and Operation Manual
X-CM-QmB-eng
Part Number: 541B029AHG
June, 2008
Observation
Cause
Resolution
Oscillating mass flow output
Bubbles dissolved in the liquid.
Use Helium as a push gas with
can cause diagnostic alarm
High pressure push gas can cause
25-50ft. of Teflon
®
tube. Helium is
bubbles to disolve in fluid. Bubbles
a light gas and can permeate the
then form at the valve due to
Teflon tube to release bubbles.
pressure drop, upsetting valve.
Oscillating pump pressure used to
Avoid using push gas. Use a pump
move the fluid. Piston action can
or bladder tank to prevent head
cause pressure oscillations,
pressure.
upsetting valve.
Pressure regulators on inlet and
outlet of QUANTIM to stabilize
pressure variations.
Oscillating mass flow output
Pressure drop or inlet pressure
Adjust pressure to original
can cause diagnostic alarm
deviates form calibrated values.
specifications.
Valve out of adjustment.
Contact Brooks Instrument.
Unstable inlet pressure.
Check external pressure regulator.
Defective PC board.
Contact Brooks Instrument.
Valves are tuned digitally and
Operate QUANTIM at specified
mechanically for a particular
Δ
P.
pressure conditions.
Valve will not open or fully close
Valves are tuned digitally and
Operate QUANTIM at specified
mechanically for a particular
Δ
P.
pressure conditions.
Proper valve response requires
just the right amount of force to be
Check valve operation with the
applied by the valve. With too
Brooks Service Tool.
much or too little
Δ
P the valve
will be mis-tuned.
Mounting attitude is different from
Mount QUANTIM in the specified
calibration attitude; Reason, gravity
mounting attitude.
effects could pull valve open or
closed.
No Flow or unable to
Insufficient inlet pressure or
Adjust pressures, inspect in-line
achieve full flow
pressure drop.
filters and clean/replace as
necessary
Clogged Valve Orifice or Sensor.
Back flush the device with a
solvent or purge gas with valve
override "Open" (if controller).
If the device has an external
Table 4-1 Troubleshooting
