If the device does not turn on at all when you press the on/off switch, then there’s almost certainly something wrong with the electrical circuit.

It is important to check this from the mains all the way to the electric pump.

So, as with all devices, first check you have power in the socket and that the device is correctly plugged in.

As you can see, this is a simple two-pin plug, so there is no fuse inside. The cable can, however, easily get damaged with use. So next, you need to check its continuity. To do this, you will need to remove the cover to access the internal parts. Turn off and unplug the device before you do this. The cable comes into the machine and goes directly to the on/off switch.

Peel back the insulation covers on the entry terminals of the switch and test continuity between these and the plug. Alternatively, after exposing the entry terminals, you can plug the device back into the mains and, setting the multimeter to check the voltage, carefully make sure that the mains is reaching the switch.

If the cable is intact, then once again disconnect the device from the mains by unplugging it.

While there is no fuse in the plug, there is, however, a fuse in the electrical motor inside the device. This should be the first thing to blow if there is a power surge or other problem, so this should also be checked first.

You don’t need to take the fuse out to check it.

Likewise, in this image, the fuse is being tested after removing the pump. But normally, you would check the fuse with the pump still in place.

If the fuse is fine, next check the on/off switch. This is a double pole switch, which provides improved safety, as commonly required in medical devices.

To properly check the switch, make sure the device is connected from the mains. Partially slide back the insulation covers to expose the power terminals.

Brown is live, blue is for the neutral circuit.

It has an inlet and outlet on the switch.

While disconnected from the power, set the switch to the on position and set your multimeter to continuity mode. Place one probe on the inlet live terminal and the other on the outlet live terminal. The multimeter should show continuity.

If there is no continuity while the switch is in the on position, the switch is faulty and needs to be replaced.

Also, have a look for any visible signs of damage. Contacts can get bent or develop carbon deposits, which can affect how the switch works.

To remove the switch, disconnect the cables by gently pulling out the connectors. You may need to wiggle them slightly.

Make sure to label the cables or group them together to make reinstallation easier.

Install the new switch by reconnecting the outlet cables first, followed by the inlet cables. Ensure the wire colors match correctly and the insulation covers are properly in place.

Position the switch back into the unit.

Reconnect the suction pump to the mains and test the switch.

Once confirmed working, replace the cover and secure with screws.