Edwards A705-41-000, Instruction Manual

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A705-40-880 Issue B
Page 40 © Edwards Limited 2011. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
5.7.3 Refit the valve to the pump
1. Refer to Figure 7 . If necessary, refit the two hinge bushes (1) to the valve flap (7), then fit the valve flap to the
valve body (2).
2. Refit the valve body (2) in the exhaust manifold (3).
3. Fit the retainer (9) to the exhaust manifold (3) and secure with the four bolts (11). Tighten the bolts to a torque
of 10 Nm.
5.7.4 Leak test the pump
5.8 Change the pump oil and clean the oil-level sight-glasses

Changing the oil in a pump from hydrocarbon to PFPE (Fomblin) could potentially cause a safety hazard.
Fomblin pumps are generally used in hazardous applications which may involve the pumping of gases with
high concentrations of oxygen. If hydrocarbon oil comes into contact with gases with an oxygen
concentration greater than 25%, an explosion can occur.

Therefore, if you want to convert a pump that has been used with hydrocarbon oil to use PFPE (Fomblin) oil,
you cannot simply flush the pump with new PFPE oil. You must return the pump to an Edwards Service Centre
for overhaul and cleaning by qualified Edwards service engineers. The change in oil type requires a complete
strip down of the pump, and thorough cleaning of all parts, so that all traces of hydrocarbon oil are removed.

Ensure that you do not come into contact with the used pump oil. The gearbox oil may be hot (up to 90 °C)
and can cause injury.

The gearbox may be pressurised. To remove the oil filler-plug, undo it slowly until the vent hole is visible,
allow the gearbox to vent to atmosphere to reduce the pressure in the gearbox, then fully undo and remove
the oil filler-plug. If you do not, oil may be ejected under pressure from the gearbox.
There are two oil-level sight-glasses on the pump ( Figure 1 , items 15). You must clean both sight-glasses when you
change the gearbox oil.
WARNING
If your pump is part of an ATEX system, you must leak test the pump after re-fitting the valve to
the pump. If you fail to do so, the ATEX certification of your system will be invalid.
WARNING
Obey the safety instructions given below and take note of appropriate precautions. If you do not,
you can cause injury to people and damage to equipment.