Edwards Vapour Diffusion Vacuum Pump Diffstak 250/2000M

Adjust Valve Closed Position Indicator

Loosen the clamp screw (7) on the valve closed position indicator (1)

Slide the position indicator in the dovetail groove (3) until the gap (2) is correct

Apply a suitable thread sealant to the clamp screw (7)

Tighten the clamp screw to a torque of 0.4 Nm

Adjust Valve Open Position Indicator

Repeat Steps 1 to 3 for the valve open position indicator (6)

Adjust the gap (5) between the valve open position indicator and the end of the pneumatic actuator

Isolate the pump from the electrical supply

Wipe the radiation shield with a soft cloth

Use a suitable cleaning solution if necessary

Is the Diffstak boiler operating at a higher than normal temperature?

Allow the pump to cool and open it to atmospheric pressure

Remove the dipstick and 'O' ring

Check the fluid-level on the dipstick

Is the fluid-level below the notch mark?

Move the valve to the fully open position

Remove the screws securing the valve-plate to the shaft

Carefully withdraw the valve-shaft complete with its lever from the valve-body

Check that all parts are removed and accounted for

Inspect the removed parts for any signs of wear or damage

Document any issues found during inspection

Clean the area around the valve-body

Dispose of any waste materials properly

Isolate the Diffstak from the electrical supply

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

Disconnect the incoming supply cables at the terminal-block

Disconnect the earth (ground) cable

Disconnect the two cables to the heaters

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

Release the radiation shield together with the terminal-block