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Operation
A735-01-880 Issue C
4.8 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 is allowed to remain, the performance of the pump will be
impaired.
4.9 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.
4.10 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.
2. Close any vacuum system isolation valves to prevent suck-back into the vacuum system (where fitted).
3. Stop the pump system using the appropriate control source, that is, using the Stop button in manual control
mode (refer to Figure 9); the Start/Stop control input (refer to Table 11 , pin 3) in parallel control mode or a Stop
command in serial control mode.
4. Vent the nXDS pump system using the gas ballast control or the valve on the inlet.
5. Isolate the Mains supply.
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