Instruction manual

EXT Split Flow Compound Turbomolecular Pumps
MAINTENANCE
PAGE
24
Issue F 24 Mar 07
Is the timer set incorrectly? Increase the timer setting (refer to the
instruction manual supplied with the
EXC Controller). If the EXC
Controller still trips into Fail consult
BOC Edwards or your supplier.
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. You may need to add air-cooling
to water-cooling.
The EXC Controller trips into Fail
after 50% speed has been reached -
the first two speed LEDs are lit
(continued).
Does the EXT Split Flow Pump rotor
rotate freely?
If not, the EXT Split Flow Pump
bearings are damaged. Consult
BOC Edwards or your supplier.
The EXC Controller trips into Fail - all
the speed LEDs are lit.
Consult BOC Edwards or your
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, 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.
Symptom Check Action
Table 7 - Fault finding (Continued)