Common problems with electric showers

In this article, we explore some of the common problems that can occur in electric showers, from faulty thermal switches to blocked shower heads.


Electric showers are one of the main types of showers in the UK, alongside mixer showers and the growing trend of digital showers.

These types of showers use cold mains water only for the water supply, and are also safely connected to the mains electric for power. The water enters the shower and, as the water is passed through the internal heater tank (or heating element), it heats the water up extremely quickly, providing instant hot water. Popular examples are the Mira Jump 8.5kW and the Mira Sport 9.0kW, the latter of which is a best-selling range across the country.

But what exactly can go wrong with electric showers? In this article, we explain some of the most common problems people encounter. You can also view our video on this topic below:

Why Does My Electric Shower Keep Cutting Out or Going Hot and Cold?

  • Thermal switches failing or cutting out. The thermal switch is an important safety feature on electric showers; its purpose is to turn off electrical supplies to the heater tank in the event that the water temperature gets dangerously hot. In such cases, the thermal switch cuts off the elements (which are the actual heating parts, like the elements in a kitchen kettle) and the water will go cold. Once the water temperature cools down sufficiently, the thermal switch will allow the heating element to function normally again, providing hot water. In some situations, you may notice a hot/cold/hot/cold cycling scenario, usually caused by a blocked shower head creating back-pressure internally. Clean and descale the shower head and this may solve the problem. If it doesn't, you may have to consider inspecting and replacing the heater tank due to limescale build-up, as this presents the same symptoms. If the shower is completely cold, the thermal switch is likely faulty: a multimeter can confirm whether there is continuity - if not, it'll need replacing.
  • Blocked shower heads. A build-up of limescale and debris on the nozzles or inside the shower head can cause blockages, preventing water from exiting through the head properly. This in turn can cause back-pressure to build, leading to other problems, such as pressure relief devices blowing. Simply clean the shower head using a descaler (our own NSS shower head cleaner is great value) or replace it.
  • Kinked or damaged shower hoses. Damaged shower hoses - like blocked shower heads - cause a build-up of back-pressure that can lead to issues internally in the shower. Unfortunately, a kinked or damaged hose, especially those that have collapsed inside, will generally need to be replaced.
  • Limescale build-up in heater tanks. Because heater tanks operate much in the same manner as a kitchen kettle, limescale build-up is unavoidable. However, if the scale becomes too great, the heater tank may develop faults. Manufacturers do not recommend descaling a heater tank for safety reasons; instead it should be replaced.
  • Pressure relief devices blowing. Another safety feature of electric showers, these blow and shut down the shower completely if internal pressure in the shower is too great. See our full article on replacing pressure relief devices for more information on this common issue.
  • Seasonality. While not strictly a fault or problem, we do get a lot of customers ask us why their electric shower runs colder in the winter months. See our full article on the seasonal effects on electric showers for more information.

Electric Shower Dripping When Off

Another complaint we hear with electric showers is that they continue to drip when turned off. This can often be caused by a faulty flow or solenoid valve. It might require replacing, but you should be able to do this yourself.

Why Does the Water in an Electric Shower Suddenly Go So Hot?

This most likely means that you have an issue with the thermostat or temperature control settings. If the water suddenly goes very hot, it may be because of a faulty component in your shower - for example, if the knob controlling the temperature slips and suddenly turns to its hottest setting.

If this happens, you should check if the thermostat is set to the correct temperature. Additionally, you should check that the thermostat knob/lever is in its correct position and that it's not stuck or turning by itself.

If this doesn't solve the issue, then you may need to replace some components inside your shower, such as the thermostat or heating element. In any case it's always best to contact a qualified electrician before attempting any repairs.

Do you experience a common problem with your electric shower that we haven't listed here? Please get in touch or use the comments feature below.

Visit our YouTube channel here for more guides and tutorials.

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