Important: Disconnect mains electricity supply before handling or attempting maintenance. Always fully read and check the troubleshooting section within your product instruction manual. 

Please open up the unit and inspect the quartz sleeve, that protects the UV bulb, for hairline cracks or damage that could allow water to enter the unit.

Check the O-ring at the top of the quartz sleeve and look for any damage or twists. Remember this should be well lubricated after each maintenance to ensure the seal is kept water tight. If there are obvious signs of water ingress inside the bulb compartment, you will need to let the unit dry out, then test the unit using the following instructions; 

  • The override switch can be located on the side of the head unit on the black section.Once this has been located please press this in with the UV power switched on to see if the bulb ignites. It is important that you DO NOT look directly at the bulb if you decide to test in this way. If you find that the bulb comes on, it may well be that the body casing of your filter is not making sufficient contact with the switch and the bulb is not being activated. If this is the case you can gently mould the clip type switch back out as it is pliable metal.
If you do need to replace your bulb, please check what size your unit requires and you can find our range of bulbs listed here.

Our External Filter Set Up Guide Extended video has some fantastic troubleshooting advice starting from 5.30 minutes. It will explain what is written above and show you how to access these parts

If you have still not identified the issue, please remove the filter baskets and place back in ensuring the magnetic override on the canister does not match with the piece of metal on the canister. Try to move the head around 90 degrees at a time and this should make the bulb ignite.

If the issue persists please contact our Customer Service Team with a short video explaining the problem.