If your electric shower stops working, it’s most likely due to limescale.
Electric showers are basically instantaneous water heaters. They have a single supply of cold water which is heated on demand via an electric element. Over time, calcium deposits form on the element, just like in your kettle. This is particularly true if you live in a hard water area.
Eventually, there is so much limescale on the element that the heat doesn’t transfer to the water properly. As a result, the element gets too hot. A sensor inside the shower detects this happening, and consequently shuts off the shower. As annoying as this is, it’s actually a safety mechanism to stop the shower from overheating. You may also find that you cannot turn it back on for a few minutes. Once again, this is the shower’s safety mechanism preventing the shower from operating until the excess heat has dissipated.
In some cases, you may also detect a burning smell. Even if the safety cut-out is working, that’s not to say the excess heat isn’t damaging the shower somehow. If you do smell burning, it’s probably a bad idea to use the shower again.
Electric shower stops working – how can it be fixed?
There are several things you can try in order to get your shower going again. Take the shower head off, and run the shower on cold on its highest water flow setting for a couple of minutes. Doing this 3-4 times per year may may help to dislodge any limescale inside. You should also make sure that the shower head is thoroughly free from limescale.
Unfortunately, this won’t be a permanent fix – the shower will still eventually scale up again. In hard water areas, electric showers may only last 1 – 2 years. The only guaranteed way to solve this issue is to replace the electric shower with a shower which doesn’t heat the water itself – i.e., a mixer shower which is supplied by a combi boiler or from a hot water cylinder.