Edwards nXDS10i nXDS15i, Instruction Manual

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Gas ballast OFF (position 0). Use this setting to:
• achieve ultimate vacuum
• pump dry gases.
Gas ballast ON (position 1). Use this setting to:
• pump low concentrations of condensable
vapours
• decontaminate the pump.
5.7 Start up procedure
Use the procedure below to start up the pump:
1. Ensure that any vacuum system isolation valve is closed (if fitted).
2. With the mains supply to the pump isolated, connect a recommended lead to the
electrical socket on the pump (refer to Figure: nXDS scroll pump on page 11 ).
3. Apply power.
4. Start the pump system using the appropriate control source, that is, using the Start
button in manual control mode (refer to Figure: User interface panel on page 32 );
the Start/Stop control input (refer to Table: Logic interface connector pins on page
22 , pin 3) in parallel control mode or a Start command in serial control mode.
5. Open the vacuum system isolation valve, if fitted.
5.8 To achieve ultimate vacuum
In order to achieve the best possible vacuum, the pump should be operated with the gas
ballast control turned off. However, if the pump, or elements of the vacuum system it is
attached to, are new or have been newly fitted, some atmospheric moisture may be
present. If atmospheric moisture is present, run the pump with gas ballast on for
20 minutes before turning gas ballast off. If moisture ican remain, the performance of
the pump will be impaired.
5.9 To pump condensable vapours
Select gas ballast ON when there is a high proportion of condensable vapours in the
process gases. This will assist the vapours to pass through the pump without condensing
and keep the pump performance from degrading.
5.10 Shut down
Use the procedure below to shut down the pump:
1. If shutting the pump down prior to a period of storage, remove any process gases
by running on a gas ballast for at least one hour.
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A73501880_G - Operation