—What you are noticing
The electric shower runs but will not heat
An electric shower that runs cold usually points at the power to the element, the element itself, or the water flow.
An electric shower heats water as it passes through the unit, using a heating element fed from its own circuit. When the water runs but stays cold, the likely causes are a loss of power to the element, a failed element, or a pressure or flow problem that stops the heater switching on.
This guide describes what people notice and what is safe to do. It does not diagnose your installation; only someone who has seen it can.
What you can safely check is limited. Confirm the shower is switched on at its isolator, check whether any switch or breaker for the shower has tripped, and note whether the water pressure has changed. Everything inside the unit is sealed and should be left to someone who works on electrics.
01In short
The points that matter most
Check the isolator
The shower usually has a pull cord or switch outside the room that can be off.
Check the circuit
A tripped breaker or RCD feeding the shower stops it heating while the water still runs.
Note the pressure
Low pressure can stop an electric shower heating, for its own safety.
02Detail
What the cause usually is
Isolator or circuit off
The shower loses its heating supply while the water continues to flow.
Failed heating element
The element burns out and the water passes through without being heated.
Pressure or flow switch
A drop in pressure can prevent the heater from switching on.
03Checklist
Before calling
Check the isolator
Whether the pull cord or switch outside the room is on.
Check the board
Whether the breaker or RCD feeding the shower has tripped.
Note the pressure
Whether the water pressure has dropped or changed recently.
—In practice
Putting it into practice
Check the isolator and the shower circuit first, because a tripped breaker stops the heating while the water still runs. Note whether the pressure has changed, since low pressure can stop an electric shower heating. Leave the inside of the unit alone — it combines mains electricity and water.
Common mistakes
- Opening the shower
- An electric shower contains mains electricity and water together. The cover should only be removed by someone who works on electrics.
- Holding a tripping breaker on
- A breaker that trips again when reset points at a fault in the shower. Holding it on hides the fault.
04Questions
Questions people ask
- Why does the water run but stay cold?
- Usually because the element is not receiving power or has failed, or because low pressure has stopped the heater switching on. The isolator and the circuit are checked first.
- Can I reset the breaker myself?
- You can reset it once. If it trips again, stop and get it looked at, because the shower may have a fault that should be found rather than held on.
- Is an electric shower dangerous to open?
- Yes. It combines mains electricity and water in one unit. The cover should only be removed by someone who works on electrics.
05Related
Related guides
- The electric towel rail will not heatAnother thing people notice, with a related check.
- The under-cabinet lights will not come onAnother thing people notice, with a related check.
- When to stop resetting a breakerA related safety point or decision.
- Signs an electrical problem is urgentA related safety point or decision.
This guide sits under troubleshooting. All topics are on the guides page.
—NEXT
Shower running cold?
Tell us whether the isolator is on and whether anything tripped. We will check the circuit and the unit.