Symptom
Check
Action
The EXC300M Controller
trips into ‘Fail’ and all the
speed LEDs are on.
-
Consult your supplier or your
nearest BOC Edwards company.
The EXC300M Controller
trips into ‘Emergency’ at
any speed.
Has there been a sudden
accidental exposure of the
EXT250M to atmospheric
pressure?
Remove the gross leak. Allow the
EXT250M to cool. Restart the
EXT250M.
Has there been a
pump-to-controller cable
disconnection or failure?
Reconnect the cable. Allow the
EXT250M to cool. Restart the
EXT250M.
Is excessive vibration being
transmitted from the vacuum
system or has the EXT250M
suffered large external
shocks?
Remove or reduce the source of
vibration or shock. Restart the
EXT250M.
Has the pump rotor been
damaged or unbalanced by
foreign material, deposition
or etching?
Consult your supplier or your
nearest BOC Edwards company.
Ultimate pressure cannot
be reached.
Is the pressure limited by
water vapour ?
Bake the system and pump.
Are any of the vacuum
gauges contaminated ?
If so, clean or replace them.
Is the pumping speed
insufficient (due to poor
conductance between the
pump and the gauge or too
large a chamber) ?
Increase the conductance or
reduce the volume.
Is the backing pressure
< 0.2 mbar (20 Pa) ?
If not, check for backing line
leaks. If the throughput is high,
you may need a larger
backing-pump.
Is the high-vacuum area of
the system contaminated ?
If so, clean the high-vacuum
system.
Check the rest of your system
for leaks and contamination.
If found, clean the contaminated
areas and repair the leaks.
Remove the pump from the
system and test the ultimate
pressure of the pump alone
(see Section 2 for
specification).
If poor, check the pump for
contamination and if necessary
return the pump as described in
Section 5.3. Leak-check the
pump. If the leak rate is > 1 x
10
-7
mbar l s
-1
(1 x 10
-5
Pa l s
-1
)
consult your supplier or your
nearest BOC Edwards company.
30
EXT250M Turbomolecular Pump
Table 7 - Fault finding (continued)
