B722-20-880 Issue D
Page 28
© Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
If the inside of the EXT pump is contaminated, it may not be possible to achieve the specified ultimate vacuum, or
pump-down time may increase. In these circumstances, you should return the pump to an Edwards Service Centre,
where the pump will be dismantled and cleaned. Use the procedure given in the forms at the end of this manual to
return the pump.
You can use any organic solvent to clean the external surfaces of the EXT pump. We recommend that you use non-
CFC solvents, such as isopropanol or ethanol. Use a cleaning solution which is suitable for the contaminants on the
pump surfaces.
For environmental reasons, keep wastage of cleaning solutions and solvents to a minimum.
5.5
Fault finding
for the possible causes of faults and for the recommended actions to rectify faults.
Refer to the fault finding section of the instruction manual supplied with your EXDC Pump Drive Module for further
fault finding information.
Table 5 - Fault finding
Symptom
Check
Action
The pump does not rotate.
Check that the electrical supply is
on.
If power is supplied and the pump
still does not rotate then there is a
fault with either the pump or
controller - consult Edwards or your
supplier.
The pump is not rotating at full
speed.
Is the inlet 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
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.
