The Shower Doctor Surgery: How to replace a solenoid co

One of the most common faults you are likely to encounter if you notice your shower isn't working properly is linked back to a component known as the solenoid valve.

This valve is essential to the operation of your shower - mainly because it enables the on/off switch to function! When you press 'on', the solenoid allows water from the mains to enter the unit. Similarly, 'off' closes the valve and prevents water from passing through.

As a result, when your shower no longer seems to be working, one of the first things you should check is whether or not the solenoid coil is broken.

In order to figure out if this is the case, you need a multi meter capable of measuring its resistance - although there are some precautions you need to take for health and safety reasons when you begin to carry out this work.

These are:

  • Turn the power off at the isolating switch
  • Take the fuse out of the fuse board
  • Turn your mains water supply off


Making sure you carry out the first two steps is essential to protect yourself from potentially being shocked, while stopping your water from flowing can prevent the shower from breaking when you start removing components.

Checking the solenoid

First, you should set your meter so that it will measure in kilo-ohms. The solenoid is generally found at the bottom of the shower unit and is made up of the valve itself and a detachable coil, which when added together form a right angle that looks a little bit like a lowercase letter 'r'.

Place your two meters on the corresponding terminals of the solenoid and check your reading - if it comes to around 3.5-4 kilo-ohms then the problem isn't with this part of your shower. However, if the reading is below this measure, then you will need to replace the coil.

Solenoid valve inside a typical electric shower.
Solenoid valve inside a typical electric shower.


Removing the coil

Generally, we would recommend changing the whole valve just to be safe and rule out any other problems. However, it's usually easier from a practical point of view to swap out the coil instead. With some models, you have to take the complete valve out anyway for it to be possible to remove the coil. That said, brands like Triton often have a plate at the bottom of the unit that you can pull away to gain access to the solenoid.

Once you can reach the component, slip two screwdrivers on either side of the top of the coil and gently ease it forward to move it away from the rest of the valve.

It is at this moment that it's important you've turned your water off, as the part you're sliding the coil down is glued to the main part of the solenoid and when this glue isn't as strong as it should be the whole part can pop out, which will cause you more trouble than you need at this point!

Keep pulling and lightly twisting the coil until it is free, before disconnecting the tube terminals. Remember to take a photo of the wires before you do this so you know where each one should go when fitting the replacement - while this isn't necessarily essential, this small precaution is always good practice.

Replacing the coil

Now you're ready to fit the replacement coil, simply reattach the wires to the terminals and pop the component back into place. As you connect it to the valve, take note of any notices or pins on the valve, as these will show you how the coil should be properly fitted - meaning it should slot in without any problems.

Finally, turn the water back on, put your fuse back and switch the isolator switch back on - if the previous coil was indeed faulty, you should now once again have a fully-working shower!

If your particular issue was not covered in this article, remember you can get in touch with our customer service team, who will be happy to answer any questions and provide free advice.

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