Edwards Vapour Diffusion Vacuum Pump Diffstak 160/700P

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

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

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

Ensure the jet assembly is vapour de-greased.

Inspect the pump interior for solid deposits of pump fluid around the base.

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

Use an ultrasonic cleaning bath to remove solid deposits, if present.

Isolate the pump from the electrical supply

Allow the pump to cool for at least 45 minutes (Diffstak 250/2000 pumps)

Allow the pump to cool for at least 20 minutes (Diffstak 63/150, 100/300, and 160/700 pumps)

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

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 for discolouration or charred fluid

Is the fluid in a satisfactory condition?

Disconnect the pneumatic pipelines from the Diffstak

Remove the socket-head screws securing the valve-plate to the shaft

Valve-shaft removal for Diffstak 63/150P and 100/300P pumps

Detach the red safety cover from the pneumatic actuator

Remove the three screws retaining the actuator to the boss on the valve-body

Carefully withdraw the valve-shaft (complete with actuator) from the valve-body

Valve-shaft removal for Diffstak 160/700P pumps