The Shower Doctor Surgery: Testing a heating tank eleme

If you're having problems with the temperature of your shower, then it could be that you have an issue with your heating tank.

A common fault with the heating tank is the failure of the element - or elements - inside. These can burn out for a number of reasons, and it's often the case that they have simply reached the end of their shelf life and old age is the official cause of death.

However, it's important to be able to confirm that this is indeed the case before taking action to resolve the situation - so how do you go about doing that?

Firstly, you need the right equipment, and the only piece you really need here - other than the tools you might require to take the cover of the shower off and remove the tank itself - is a digital multi-meter. If you don't already have one, we sell these online.


Of course, you won't be able to get to the heating tank without taking off the shower's cover. However, to do this, you need to ensure your water supply and power supply are both turned off.

The deactivation of your electrics is essential for your safety, so make sure you shut it off at the isolation switch and the circuit breaker or remove the fuse - whichever is applicable.

After removing the cover, you should still double check the power is off by using a meter before sticking your hands in. Although this might seem like over-cautious stuff, it's always worth taking such precautions for the sake of a couple of seconds, as you can never be 100 per cent sure where the source of the shower's electricity is - especially if you didn't fit it yourself. Once you're certain it's safe to work around, then you are ready to get to work without risking shocking yourself.

The tank

Heating tanks come in a range of shapes and sizes, from small, squat tanks to long tanks and ones that resemble almost a cuboid shape. Additionally, it's worth noting that they aren't all made of the same materials - and your tank may be metal, plastic, or a bit of both.

Either way, they all have a couple of things in common - they have a place where water can come in and out, and they have elements inside, although the number of these may vary between models.

Inside, the elements look a bit like the old fashioned kettle elements (like a big coil), although you'll be testing them from the outside of the tank, so it's unlikely you'll see this unless you're intent on pulling the whole thing apart.


With your multi-meter to hand, put the black probe where the blue wire connection is, and the red probe should be placed upon either the brown or black wire, depending on what sort of shower you have.

You're checking for resistance here and should be measuring in Ohms. If there is a resistance of between 11 and 18, then the element is working as it should, although the exact amount will depend upon how powerful the shower is.

If your meter reads a 1 or a 0, then there is no resistance - which indicates one of the elements has blown. At this point, your only option is to replace the tank.

At The Shower Doctor, we appreciate that just reading about tasks such as this might not be enough, which is why we have created a series of how-to guides on YouTube as well. Check out the video on testing your heating tank element inside an electric shower here.

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