Electric shower not working: what to check first

Which kind of "not working" is it?

Electric showers fail in a handful of distinct ways, and each points to a different part. Try the shower once and note exactly what happens before you do anything else.

No power: nothing happens at all

Every electric shower has its own isolating switch, usually a pull cord on the bathroom ceiling or a large switch on the wall outside the bathroom. It often has a small neon or light that shows when it is on. Pull it once and check the light. It is easy for someone to switch it off by mistake, especially after cleaning.

Next, look at the consumer unit. The shower usually has its own breaker, often labelled, and may be protected by an RCD. If it has tripped, you can switch it back on once. If it trips again straight away or as soon as you start the shower, leave it off. That is a fault, and resetting it again and again will not fix it.

If the isolator is on, the breaker has not tripped and there is still no sign of life, the problem is inside the unit or its wiring, and it needs an engineer.

If you notice a burning smell, scorch marks, a melted pull cord or switch, or water near the electrics, turn the shower off at the isolator if you can do so without touching anything wet, and switch off its breaker. Do not use the shower until it has been checked.

Power but no water

Electric showers are fed straight from the cold mains. Most have a small isolation valve on the pipe feeding them, sometimes behind a removable panel near the shower or in an airing cupboard. If work has been done recently, check it has not been left closed. Also check whether the other cold taps are running normally. If the whole house has low pressure or no water, the shower cannot run either; our guide to no water coming out of the taps covers that. If the shower only struggles in the morning and evening, read why water pressure drops at busy times.

London has hard water, and scale builds up quickly in shower heads and hoses. A blocked head holds back enough water that the shower may refuse to run, cut out or swing between hot and cold. Unscrew the head, soak it in descaler or white vinegar, rinse it and try again. Check the hose for kinks too. If the flow is weak rather than stopped, our guide to low water pressure in the shower covers the other causes.

Inside the unit there is an inlet filter and a solenoid valve that opens when you press start. If the head and supply are fine but no water flows when the unit is on, one of those has usually blocked or failed. Both are replaced by an engineer, not the householder.

Our guide on how to descale a shower head explains the method in more detail, including heads that do not unscrew.

Water but no heat

Check the setting first. Many electric showers have a power selector with cold, economy or low, and full power settings. In winter the incoming mains water is much colder, so a shower that was fine in summer on a lower setting can feel cold now. Turn the power to full and the temperature control to hot, and run it for a minute.

If it is still cold, the heating element may have burnt out, or a thermal cut-out inside the unit may have tripped. Cut-outs are safety devices that switch the heater off if the unit overheats, and they usually trip because the flow has been too low, often from a scaled head. Some reset, some need replacing, and either way the cause needs finding. If your electric shower keeps cutting out rather than running cold from the start, our separate guide covers that pattern. If you are not sure you have an electric shower, our guide for when there is no hot water in the shower but the taps are fine explains how to tell the types apart.

Leaking from the bottom of the unit

Most electric showers have a pressure relief device that bursts or opens to protect the unit if the outlet is blocked, for example by a badly scaled head or a closed outlet. When it operates, water runs out of the bottom of the shower case. Switch the shower off at the isolator and do not use it. The device, and whatever caused the blockage, must be dealt with by an engineer, and on an older shower it is often the point where replacing the unit makes more sense than repairing it.

Repair or replace?

Elements, solenoid valves, pressure relief devices and switches can all be replaced if parts are still available for the model. The engineer will tell you what has failed and whether the parts are available before starting any repair.

If the shower is old, parts are hard to find, or it has had several faults, a new unit may be the better choice. A like-for-like replacement is usually straightforward. A more powerful shower needs its cable and circuit protection checked to make sure they can carry the higher load, and new circuits in a bathroom are notifiable electrical work that has to be done and certified by a qualified electrician. Our guide to a mixer or electric shower compares the options if you are thinking of changing type.

What an engineer will check

With the power isolated, the engineer will check the supply, the inlet filter and the solenoid valve, the heating element, the thermal cut-outs and the pressure relief device, and look for signs of overheating on the terminals and cable. They will measure the flow at the shower and check the mains pressure, because many electric shower faults start with too little water going through the unit.

It helps if you can tell us the make and model, usually printed on the front or under the cover, and describe exactly what happens when you press start. If it is a Mira, our Mira shower not working guide covers the checks Mira recommends and its own repair service; for an Aqualisa, see our Aqualisa shower not working guide.

Get your shower working again

Loyal Plumbers covers London and everywhere inside the M25, 24 hours a day, with 10 vans on the road, and repairs showers and connects replacement units as part of our bathroom plumbing work. Call 020 4652 8585 and tell us what happens when you switch the shower on.

Our call-out charge is £60, and the engineer explains what they have found and what the repair or replacement involves before starting. You can read more on our hot water repair page and our bathroom fitting page.