Edwards Vapour Diffusion Vacuum Pump Diffstak 160/700M

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?

WARNING: Remove all traces of the cleaning solution before you operate the pump.

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

Ensure the jet assembly is vapour de-greased

Pump Interior Inspection and Cleaning

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

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.