B756-01-880 Issue K
Page 26 © Edwards Limited 2013. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
The EXC Controller trips into Fail
after 50% speed has been reached -
the first two speed LEDs are lit.
Is the pressure too high? If so, reduce the pumping load or
check for a gross leak into the
system.
If the high gas load is temporary,
configure the EXC Controller to delay
the Fail trip on 50% speed and set an
appropriate delay time (refer to the
instruction manual supplied with the
EXC Controller).
Is the EXT Split Flow Pump running
too hot?
Increase the cooling water flow or
decrease the water temperature or
do both. Air cooling may need to be
added to water cooling.
Does the EXT Split Flow Pump rotor
rotate freely?
If not, the EXT Split Flow Pump
bearings are damaged. Consult
Edwards or the supplier.
The EXC Controller trips into Fail -
all the speed LEDs are lit.
Consult Edwards or the supplier.
System operating pressure cannot be
reached.
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 interstage inlet pressure
> 0.2 mbar (20 Pa)?
If the interstage inlet pressure is too
high, inlet pressure at the
turbomolecular inlet is reduced;
ensure that the interstage inlet
pressure is < 0.2 mbar (20 Pa).
Is the backing pressure < 12 mbar
(1200 Pa)?
Check for backing line leaks. If the
backing pressure is too high, a larger
backing pump may be required.
Is the high-vacuum area of the
system contaminated?
If so, clean the high-vacuum system.
Check the rest of the system for
leaks and contamination.
If found, clean the contaminated
areas and repair the leaks.
The EXT Split Flow Pump is very
noisy or there is excessive vibration
or both.
Is the pump rotational speed the
same as the resonant frequency of
the attached system?
If so, change the natural frequency
of the attached system.
Is the vibration being transmitted
from the rotary pump?
If so, fit flexible bellows or a
vibration isolator in the backing line.
Is the noise irregular and getting
progressively worse?
If so, a bearing is defective. Consult
Edwards or the supplier.
Is the EXT Split Flow Pump making a
constant high-pitched noise?
If so, the rotor is out of balance.
Consult Edwards or the supplier.
None of the above. - Consult Edwards or the supplier.
Table 7 - Fault finding (continued)
Symptom Check Action
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