If you find the device turns on, but you are having problems setting the correct pressure, there may be a problem with either the pressure gauge or the regulator knob. In this film, we will look at problems with the regulator.

To assess, repair, or replace the vacuum regulator knob, first take off the cover from the base and remove all the tubing as shown in the previous film.

The regulator knob is held in place by a nut on the inside of the casing, which you need to undo. You can use locking pliers for this or a spanner.

Once the nut is off, you can slide the regulator out from its port.

You can see that there is a small hole which opens and closes as you adjust the regulator knob. This hole allows air from the atmosphere to enter the system to gradually reduce the pressure. The pressure goes down when you turn the knob clockwise and the hole gets bigger. If you turn the knob anticlockwise, the hole should get smaller, increasing the pressure.

So to assess whether the pressure regulator is working, you need to check that the hole is opening and closing when you rotate the knob. Sometimes the mechanism gets stuck or damaged, in which case you may need to replace the whole regulator.

The new knob will probably come with a nut attached to it, so first take this off. Now place the new knob into the hole on the top of the casing. Holding it there, turn the casing over and put back the nut, gently tightening it using the adjustable spanner.

Next, put back the tubing and reassemble the device. We will show you how to do this in a later video.