© Edwards Limited 2011. All rights reserved. Page 29
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Maintenance
S149-01-880 Issue F
5.4 Oil change
z Lockout all energy sources connected to the pump and vent to atmosphere.
z Review the process contaminants and select proper personal protective equipment (PPE) to protect against
media contact.
z Using the drain valve, drain the oil into a suitable container for disposal. Use only Edwards recommended oils
when refilling the pump. Refer to Section 2 for fluid type and quantities. Fill the pump until the sight glass
reaches the 3/4 mark.
z Check the pump and system for potential hazardous conditions. Restore energy sources.
5.5 Oil level check
z Check oil level daily. The oil level should be at center of sight glass when the pump is off or in lower half
while pump is operating at high vacuum. The level will change depending on inlet pressure. In most cases, oil
is added after operating the pump for a short period of time.
z To avoid the loss of oil out the fill hole, do not add oil to the pump when in operation.
Note: When pumping gases that contain water vapor, it may be necessary to remove the water that condenses in
the pump reservoir sump. Stop the pump and wait at least 1/2 hour for the oil and water to separate. Open
the oil drain valve and drain water; close the valve when oil flow starts. The interval is process dependent
and varies with the amount of water vapor and oil temperature. Operating the pump with the oil
temperature near 71 °C (160 °F) will minimize formation of water but not eliminate it.
Water entrapped in the oil will decrease ultimate vacuum and increase pumpdown times. The presence of water in
the oil is evident by a milky appearance of the oil when running.
5.6 Valve deck maintenance
z Lockout all energy sources connected to the pump.
z Drain the oil as described in Section 5.4.
z Remove the reservoir cover, oil baffle, and each valve deck while being very careful not to drop any
hardware inside the pump.
z Replace worn valve deck or valve deck parts. Reinstall valve decks with new gaskets. Reinstall oil baffle with
new gasket.
z Reinstall oil reservoir cover.
z Refill the oil as described in Section 5.4.
z Check the pump and system for potential hazardous conditions. Restore energy sources.
The oil fill plug on the top of the pump serves a dual purpose. It is an oil fill port and an over-
pressure device that opens at between 8 and 14 psig. This device is to protect the pump from oil
box over-pressure and possible side cover fracture. The 412J pumps are fitted with two oil fill
plugs, ensure at least one of these is free from obstruction i.e. not connected to anything.
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