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Page 17
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MAINTENANCE
B756-50-880 Issue C
4. Repeat the above procedure with the second Ø159.5 O-ring and fit it into the second O-ring land, halfway up the
cartridge pump.
5. Repeat the procedure in step 3 with the Ø133 O-ring and fit it to the uppermost O-ring land.
6. With the nylon jacking screws of the new pump fully retracted into the flange of the cartridge pump, and the
exhaust port facing down, position the pump at the mouth of the chamber, taking care to ensure that the fixing
holes are aligned with threaded holes in the chamber.
7. Slowly insert the pump into the chamber, taking care not to damage the surfaces of the bore or the O-ring lands,
until the piston seal at the EXDC160 end rests on the lip of the chamber as shown in
5.4
Pressing the pump in place with the fixing bolts
1. Fit the four M6 x 30 cap head bolts and flat washers into position and finger tighten.
2. Tighten the four bolts by half turns at a time in turn, ensuring that an equal number of turns are applied to each
bolt until the pump is uniformly pressed into the chamber. The three piston seals will now be pushed into
position at their separate stages along the chamber wall.
3. Once the pump has been pressed fully home, tighten the four fixing bolts to a torque of 10 Nm.
4. Refit the EXDC160 controller and the vacuum backing line as shown in
, ensuring that they do not form
slip or trip hazards. Refit any safety earth connections as appropriate. Refer to any system operating instructions
provided.
5. Restart the system in accordance with the operating instructions and ensure leak tightness.
6. The O-ring piston seals fitted to the cartridge pump should be replaced whenever the cartridge pump is removed
from the chamber. Select the inlet screen according to the pump inlet flange size. Contact the system supplier if
new O-ring seals are required.
5.5
Bearing maintenance
When supplied, the pump contains sufficient lubricant to supply the bearings for life. No routine maintenance is
therefore required between bearing replacements. The bearings are not user-serviceable. The bearings will need to
be replaced when they reach the end of their service life. This is typically more than 20,000 hours, but may be less;
this depends on the type of pumping duty on which the pump is used.
When the bearings need replacement, Edwards recommends exchanging the pump for a factory-reconditioned
replacement. Alternatively, send the pump to an Edwards Service Centre to have the bearings replaced.
When returning EXT70/70/200H pumps to Edwards Service Centres, use the procedure included at the end of this
manual. Note that the instruction to drain all fluids does not apply to the lubricant in the EXT70/70/200H pump oil
reservoirs.
5.6
Rotor life
The fatigue life of the EXT Turbo-pump rotors is typically 40,000 to 50,000 cycles. As a precautionary measure,
Edwards recommends that pumps are returned for a major service (rotor replacement) after 20,000 cycles of
acceleration to full speed and back to a stop, or after ten years of use, whichever occurs first.
5.7
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 the EXDC160 Controller for further fault
finding information.
