Edwards EXT Series - Page 35

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Maintenance
B753-03-880 Issue F
The EXC Controller trips into Fail
during the ramp-up and before 50%
speed is reached.
Is the inlet pressure too high? Is the
backing pressure too high?
If so, reduce the pumping load, or
check for a gross leak into the
system.
Is the EXT pump running too hot? Increase the cooling-water flow or
decrease the water temperature or
do both. You may need to change
from air-cooling to water-cooling.
(Refer to Section 2 for maximum
inlet pressure and cooling
requirements). Check that external
heat sources (such as system bakeout
heaters) are not excessive.
Does the rotor rotate freely? If not, the EXT pump-bearings are
damaged. Consult Edwards or your
supplier.
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
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 pump running too hot? Increase the cooling-water flow or
decrease the water temperature or
do both. You may need to change
from air-cooling to water-cooling.
Does the EXT pump rotor rotate
freely?
If not, the EXT pump-bearings are
damaged. Consult Edwards or your
supplier.
The EXC Controller trips into Fail -
all the speed LEDs are lit.
- Consult Edwards or your supplier.
Table 4 - Fault finding (continued)
Symptom Check Action