Shower runs coldwhat to check
Water flows but never heats. On an electric shower this is nearly always the supply, the flow through it, or an element that has stopped working.
Take care
What this means
An electric shower heats water in one place and one place only: a tank inside the unit with heating elements in it, which switch on when the appliance detects water flowing and switch off when it does not. So a shower that flows cold has failed at one of three points, and they are worth separating because two of them are yours and one is not.
The first is the supply. If the elements are getting no power the shower becomes, in effect, a cold tap — water passes through untouched. That is what a tripped breaker, a blown fuse or an isolator that has been switched off looks like from inside the cubicle, and it is why every manufacturer starts their cold-water fault list with the consumer unit rather than with the shower. Triton put it first in theirs and so does Redring. The second is flow. Every one of these appliances has a low-pressure or flow cut-out whose job is to disconnect the elements when there is not enough water moving to carry the heat away, because an element heating a static tank is how a shower catches fire.
When that cut-out operates you get flow without heat, and the shower is protecting itself rather than failing. The third is the element or the protection around it, and that is the one that needs somebody. On most brands a shower that has cold water, full pressure and a lit power neon has an element or a thermal cut-out that has opened, and neither is an owner part.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| No power reaching the elements | A tripped breaker or blown fuse leaves the solenoid opening and the water flowing while nothing heats it. The commonest cause by a distance. | Common |
| Low pressure or flow cut-out has operated | Not enough water is moving for the shower to heat safely, so it has disconnected the elements and let the water carry on. Protection working, not a failure. | Common |
| Power selector left on cold or low | The selector is a mechanical switch choosing how many elements are energised. On its lowest setting in a cold month the result is barely warm water. | Occasional |
| Heating element failed | An open-circuit element gives full flow and no heat at all, with everything else on the shower behaving normally. | Occasional |
| Thermal cut-out has operated | The safety device has opened and taken the elements out of circuit. On some brands it resets and on others it has to be replaced. | Occasional |
What to try yourself
Check the consumer unit for a tripped breaker or RCD on the shower circuit. If one has tripped, note it — that changes the answer and is covered on the tripping page rather than here.
If the breaker trips again the moment you reset it, stop. Repeatedly resetting a circuit that keeps tripping is the one thing not to do.Confirm the pull cord or wall isolator is on and that the power neon on the shower is lit. No neon with the cord on means the fault is in the supply rather than in the shower.
Check the power selector is on its highest setting and the temperature control is not wound fully to cold, then run the shower for a minute before judging it.
Take the showerhead off and run the hose into the tray. If the water heats with the head removed, the head was restricting flow and the shower was protecting itself.
Clean the inlet filter if your brand lets you. On a Bristan it is an owner job: isolate the electricity and the water, and the filter cap turns anticlockwise with a large flat-blade screwdriver from outside the unit. On a Triton, a Mira or a Redring the filter is inside the case and the manufacturer reserves it for the installer or a competent person, so book it rather than open the cover. Silt and scale collect there and reduce flow enough to hold the cut-out open.
Isolate the shower at the pull cord first, and turn off the water at the servicing valve on the inlet pipe rather than at the mains for the whole house. Do not remove the front cover of a Triton, Mira or Redring to reach the filter; their guides put that job on the installer’s list.If there is full flow, a lit neon and still no heat, stop there. An element or a thermal cut-out is behind the cover and that is the point at which this becomes somebody else’s job.
Get a qualified electrician to look at your electric shower
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified electrician, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What it costs to fix
Typical repair cost
£0–£180
Time on site
20 minutes
Nothing if it is a breaker, a selector or a blocked head. An element or thermal cut-out replacement is typically the low three figures fitted, at which point the age of the shower decides whether it is worth it.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related electric shower fault codes
- Shower keeps tripping the electricsStop — call an engineerA shower that trips the breaker or RCD is reporting a real electrical fault. Do not keep resetting it to get one more shower out of it.Related: same brand
- Shower completely deadGet it checkedNo neon, no water, nothing when you pull the cord. On an electric shower a total dead is almost always the supply rather than the appliance.Related: same brand
- Thermal cut-out has operatedGet it checkedThe safety device has taken the elements out of circuit. Whether you can reset it yourself depends entirely on the brand, and the answers differ.Related: same brand
- Water suddenly scaldingGet it checkedAn electric shower that runs too hot is usually short of flow rather than making too much heat. The exception is a thermostatic model, which should not do this at all.Related: same brand
- Burning smell from the shower or pull cordStop — call an engineerHot plastic, scorching or discoloured fittings on a shower circuit is an overheating connection. Switch the circuit off at the consumer unit and leave it off.Related: same brand
- Water leaking from the shower unitGet it checkedWater escaping from the casing rather than the head puts mains water inside a live appliance. Manufacturers say stop using it, and that is the right answer.Related: same brand
Related guides
Common questions
Why does the water still flow if the shower is not heating?
Because the water valve and the elements are separate. The valve opens whenever you start the shower, and the elements are switched independently. Losing the heating side leaves you with a cold tap that works perfectly.
It was fine yesterday and cold today with nothing changed. What happened?
Two things do that overnight. A breaker that has tripped, which you will see at the consumer unit. Or a cut-out that has operated, which you will not see at all — the shower simply stops heating and everything else behaves normally.
Is it worth repairing or should I replace it?
An element or a cut-out on a shower under about five years old is usually worth doing. Past that, the cost of the visit plus the part often approaches the cost of a new unit fitted on the same circuit, and the rest of the shower is the same age as the bit that failed.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.