Electric Shower Not Working: Causes and Safe Checks

Updated July 2026 · Emergency Plumber Chelsea

Start with what the shower is doing. An electric shower heats cold mains water as it passes through the unit, so it has no link to your boiler or hot water cylinder. That makes it easier to diagnose, because there are only two things going in, electricity and cold water, and a handful of parts inside. Before touching anything, note whether the display or indicator lights come on, whether any water comes out, and whether it is warm, cold or changing. Each fault below starts from one of those symptoms.

Completely dead, no lights and no water. Check the ceiling pull-cord or wall switch first; most have a small neon or indicator light that shows when it is on, and it is easy for someone to have switched it off. Then look at the consumer unit. An electric shower has its own circuit, and if that breaker has tripped, or the RCD protecting it has dropped, the shower gets no power. You can reset a breaker once. If it trips again straight away, or trips every time the shower is switched on, leave it off. That points to an electrical fault in the shower or its wiring, often water getting inside the unit or a failing element, and it needs an electrician or shower engineer to test it, not repeated resets.

Lights on but no water. If the display lights up and you can hear a click when you press start, but little or no water comes through, check the water side. Is the isolation valve on the cold supply to the shower fully open? Someone may have closed it during other work. Is the rest of the house getting cold water at normal pressure? If the kitchen tap is weak too, the problem is the incoming supply, and our guide to low water pressure covers the causes. If the house supply is fine, the likely culprits inside the shower are a blocked inlet filter or a failed solenoid valve, the electrically operated valve that opens when you press start. Both are inside the unit.

Water coming out of the bottom of the unit. Most electric showers have a pressure relief device inside, a safety part that opens and dumps water out of the base of the unit if pressure builds up where it should not. The usual trigger is a blocked shower head or a kinked hose, both of which stop water leaving freely. On many models the pressure relief device is a one-off part: once it has operated, it has to be replaced, and descaling the head will not reset it. Clear the head and hose so it does not happen again, but expect the device itself to need changing. Keep the shower off until it is looked at if water is running out of the unit.

Water flows but stays cold. If you get a normal flow but no heat on any setting, first check the setting itself. Many showers have a cold or economy position, and a knocked power selector is a surprisingly common cause. If the setting is right, the likely faults are the heating element, which can burn out after years of hard London water, or the thermal cut-out, a safety switch that cuts the element if the unit overheats. On some models the cut-out resets once the unit cools; on others it needs resetting or replacing inside the unit. A thermal cut-out that keeps tripping is a symptom rather than the fault, usually of scale or poor flow causing the unit to overheat. Our guide to a shower that runs cold covers the same symptom on mixer showers.

Low flow can stop the heater switching on at all. Electric showers only power the element when enough water is flowing through, and they need a minimum working pressure set by the manufacturer, which you will find in the manual. If the incoming pressure is borderline, the shower may run cold or cut in and out, especially when someone uses a tap or the washing machine at the same time. Upper-floor flats in older Chelsea mansion blocks sometimes have a weak cold feed for exactly this reason. Our guide on how to improve shower pressure explains how pressure is measured and what can be done about it.

Too hot, then too cold. An electric shower sets temperature by controlling how fast water passes through the heater: slower is hotter, faster is cooler. If the flow rises and falls because of scale in the head, a partly blocked filter, or other taps in use, the temperature swings with it. In winter the incoming mains water is much colder, so the same flow comes out cooler and you need to turn the flow down to get the same warmth. That is normal, not a fault. A temperature that swings wildly even with nothing else running needs the unit checking.

Descale the head and check the hose. This is the one job worth doing yourself, because a scaled head is behind low flow, temperature swings and a tripped pressure relief device. Unscrew the head, soak it in descaler or a vinegar solution, rub the nozzles clear and rinse it. Straighten the hose and check it is not kinked where it hangs or is trapped by a riser clamp. Chelsea is supplied with hard water, and our guide to hard water and limescale explains why showers here scale up faster than people expect.

Do not take the cover off. The inside of an electric shower has mains electricity and water within inches of each other, and the element runs at a high current. Even with the pull-cord off, do not open the unit yourself. Signs of a dangerous fault include a burning or hot plastic smell, scorch or brown marks on the pull-cord switch or the shower cover, a switch that feels warm, or crackling from the unit. If you notice any of these, switch the shower off at the consumer unit and leave it off until it has been inspected. Scorching at the switch often means a loose connection or a cable that is struggling with the load, which is electrical work.

Repair or replace? A single failed part in a newer shower, such as an element, solenoid or pressure relief device, is usually worth repairing if parts are available. If the unit is old, heavily scaled, has several faults, or the parts are no longer made, a replacement tends to make more sense. A like-for-like swap of the same power rating onto an existing circuit is the simplest option. A more powerful unit may need a bigger cable from the consumer unit, and that part must be done by a qualified electrician. Our guide to an electric vs mixer shower is worth reading if you are deciding whether to stay electric.

Plumber or electrician? If the fault is on the water side, a blocked filter, solenoid, pressure relief device, leaks, low flow or the unit itself needing to be swapped, a plumber is the right call. If the breaker or RCD keeps tripping, the switch is scorched, or the circuit needs upgrading, you need an electrician. Emergency Plumber Chelsea handles the plumbing side of electric shower repairs and replacements through our shower repairs service, and we will tell you plainly if the fault is electrical. If water from the shower has leaked through to the room below, our bathroom plumbing team can trace and fix it. Call 020 3002 6667 for Chelsea, Knightsbridge, Sloane Square, South Kensington and Fulham. There is no call-out fee on jobs over 3 hours.

Quick tips

• Check the pull-cord switch and the shower's breaker in the consumer unit before anything else.
• Reset a tripped breaker once only. If it trips again, leave it off and get it tested.
• Water coming out of the base of the unit usually means the pressure relief device has gone, often after a blocked head.
• Descale the shower head regularly; in hard-water Chelsea it protects the whole unit.
• Never open the shower cover yourself, and switch off at the consumer unit if you smell burning or see scorch marks.

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