A352-03-880 Issue B
Page 18 © Edwards Limited 2015. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Operation
Use the following procedure to achieve ultimate vacuum:
1. Isolate the pump from the vacuum system.
2. Turn the gas ballast control fully anticlockwise (fully open) and operate the pump for at least 1 hour (or
overnight) to thoroughly purge the oil of contaminants.
3. Close the gas ballast control.
4. Open the vacuum system isolation valve and pump down to ultimate vacuum.
4.4 To pump condensable vapours
Use gas ballast when there is a high proportion of condensable vapours in the process gases.
1. Close the vacuum system isolation valve.
2. Turn the gas ballast control fully anticlockwise (fully open) and operate the pump for 30 minutes to warm the
oil. This will help to prevent vapour condensation in the pump.
3. Open the vacuum system isolation valve and continue to operate the pump with the gas ballast control open.
After pumping condensable vapours, the oil can be decontaminated (if necessary) using the procedure in Section 4.5.
4.5 To decontaminate the oil
Look at the condition of the oil in the sight glass (Figure 10, item 1). The oil in the pump should be clear. If the oil
is cloudy or discoloured:
1. Close the vacuum system isolation valve.
2. Turn the gas ballast control fully anticlockwise.
3. Operate the pump until the oil is clear.
4. Change the oil if it remains mid-brown in colour.
4.6 Unattended operation
The pump is designed for unattended operation under the normal operating conditions specified in Section 2.
However, Edwards recommends checking the pump at a regular interval of not more than 14 days. Check the pump
more frequently if pumping high volumes of gas or if operating the pump with the gas ballast control open.
4.7 Shut down
Edwards recommends decontaminating the oil before shutting down the pump. Decontamination of the oil will
prevent damage to the pump by the contaminants in the oil.
1. Refer to Section 4.5 and decontaminate the oil, as required.
2. Close the vacuum system isolation valve (if not already closed).
3. Turn the gas ballast control fully clockwise to close.
4. Switch off the electrical supply to the pump.
4.8 Long-term shut down
If the pump will be out of service for a long period of time (more than 3 months) or will not be put into service until
a later date, do not drain the oil.
Blank openings with protective caps and store the pump in a dry place. The pump must not be stored in a place that
is damp and/or subject to large temperature variations.
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