Edwards Vapour Diffusion Vacuum Pump Diffstak 100/300F

Allow the Diffstak pump to cool and open it to atmospheric pressure

Switch on the pump heater for a maximum time of two minutes to warm the pump fluid

Disconnect the Diffstak from the electrical supplies and detach it from your vacuum system

Remove the drain-plug and allow the fluid to drain from the pump

Visually check the interior of the pump

If the pump fluid has deteriorated, clean the pump as detailed in Section 5.5

If the fluid is satisfactory, refill the pump as detailed in Section 3.9 and refit it to the system

Isolate the pump from the electrical supply

Wipe the radiation shield with a soft cloth

Use a suitable cleaning solution if necessary

Isolate the Diffstak from the electrical supply

Remove the retaining screws and detach the cover from the terminal-box

Disconnect the incoming electrical supply cables and the earth (ground) cable at the terminal-block

Remove the nut from the radiation shield/heater assembly securing stud

Lower the complete radiation shield and heater assembly

Disconnect the electrical connections at the heater and remove the heater

Choose the cleaning solution suitable for the type of pump fluid used.

Ensure all traces of the cleaning solution are removed before operating the pump.

Pump Interior Inspection and Cleaning

Inspect the pump interior for solid deposits of pump fluid.

Is there a solid deposit of pump fluid around the base?

Use an ultrasonic cleaning bath to remove deposits if present.

Wash the interior of the pump and the pump interior components with the selected cleaning solution.

Removal of Damaged Position Indicators

Refer to Figure 27 and loosen the clamp screw on the valve open position indicator.

Slide the valve open position indicator down the dovetail groove and out of the cylinder.

Loosen the clamp screw on the valve closed position indicator.

Slide the valve closed position indicator down the dovetail groove and out of the cylinder.

Installation of New Position Indicators

Ensure the dovetail groove is clean.

Slide the new valve closed position indicator into the dovetail groove, ensuring correct orientation as shown in Figure 27.

Adjust the position indicator until the gap between the position indicator and the valve actuator is correct.