Edwards Vapour Diffusion Vacuum Pump Diffstak

Adjust Valve Closed Position Indicator

Loosen the clamp screw on the valve closed position indicator

Slide the position indicator in the dovetail groove until the gap between the position indicator and the valve actuator is correct

Apply a suitable thread sealant to the clamp screw

Tighten the clamp screw to a torque of 0.4 Nm

Adjust Valve Open Position Indicator

Repeat adjustment steps for the valve open position indicator

Verify the following adjustments are complete

Open the pump to atmospheric pressure

Remove the dipstick and 'O' ring

Check the fluid-level on the dipstick

Is the fluid-level below the notch mark?

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

Drain the pump fluid as detailed in Section 5.4.

Disconnect the following connections

Remove the pump from the system.

Remove the valve-plate from the shaft (refer to Sections 5.5.2 and Section 5.5.3).

Examine the valve-plate seal and the 'O' rings on the valve-shaft for wear or damage.

Isolate the pump from the electrical supply

Wipe the radiation shield with a soft cloth

Use a suitable cleaning solution if necessary

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.

Ensure the pump fluid is not vaporised.

Disconnect the Diffstak from the electrical supplies.

Detach the Diffstak from your vacuum system.

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