Electric Shower Not Working: Troubleshooting Guide

Electric Shower Problems

Electric showers are reliable, but when they fail it's often at the worst possible time. Here's how to diagnose the problem and who to call.

Common Symptoms

Troubleshooting Steps

Step 1: Check the Obvious

Before panicking:

• Is the shower switch on? Check the pull cord or wall switch
• Is there power? Check indicator light on unit
• Is water flowing? Turn tap to check mains pressure
• Has RCD tripped? Check consumer unit

Step 2: Identify the Symptom

No Power at All:

• Pull cord switch may be faulty
• Fuse may have blown
• Wiring fault
• RCD/MCB tripped

Power but No Heat:

• Heating element failed
• Thermal cutout activated
• Pressure switch fault
• Solenoid valve stuck

Water Runs Cold then Hot:

• Thermal cutout cycling
• Element failing
• Flow rate too high

Showers Trips the Electrics:

• Earth fault in unit
• Water ingress
• Wiring fault
• Failed element

Step 3: Check the Isolator Switch

Most electric showers have a 45A double-pole isolator switch:

• Usually a ceiling pull cord in bathroom
• Or a wall switch outside bathroom
• Check it's in the 'on' position
• May have a small indicator light

Common Problems Explained

1. Thermal Cutout (TCO) Tripping

Electric showers have safety cutouts that trip if:

• Water flow is too low
• Temperature gets too high
• Limescale reduces flow

Signs:

• Shower cuts out mid-use
• Works briefly then stops
• Power light stays on but no heat

Common Fix: Often limescale buildup - may reset when cooled, but will keep happening.

2. Heating Element Failure

The element that heats the water can fail:

• Complete failure - no heat at all
• Partial failure - weak heating
• Earth fault - trips electrics

Average element lifespan: 5-10 years

Replacement: Often more economical to replace entire shower.

3. Pressure Switch Problems

The pressure switch ensures element only heats when water flows:

• Stuck switch - no heat despite water
• Faulty switch - intermittent operation
• Debris blocked - unreliable operation

4. Solenoid Valve Issues

Controls water flow into unit:

• Stuck closed - no water flow
• Stuck open - water runs constantly
• Partial blockage - poor flow

5. Limescale Buildup

Devon's water varies by area, but limescale affects:

• Heating element efficiency
• Spray plate and hose
• Pressure switch operation
• Solenoid valve

Prevention: Regular descaling, consider water softener

When the Electrics Trip

If Your Shower Trips the RCD

This is a safety response - don't keep resetting and trying.

Possible Causes:

• Water inside the unit
• Failed heating element
• Damaged wiring
• Earth fault

Action: Leave off and call an electrician.

If the MCB (Circuit Breaker) Trips

Different from RCD - indicates overload or short circuit:

• Possible element short circuit
• Wiring fault
• Wrong MCB rating

Electric Shower Safety

Isolation Before Any Work

Electric showers use high current (typically 8-10.5kW):

• Must be isolated at consumer unit before any work
• Double-pole switch means both live and neutral cut
• Never work live - extremely dangerous

Who Can Work on Electric Showers?

Replacement vs Repair

When to Repair

• Less than 5 years old
• Known simple fault
• High-quality unit
• Repair cost < 50% of replacement

When to Replace

• Over 8-10 years old
• Multiple previous issues
• Obsolete model (no parts)
• Repair cost > 50% of replacement

Replacement Costs

Upgrading Your Electric Shower

When to Consider

• Current shower underpowered
• Want better performance
• Replacing old unit anyway

Upgrade Considerations

Cable upgrade cost: £80-200 (depends on run length)

Frequently Asked Questions

Why does my electric shower go hot and cold?

Usually thermal cutout cycling due to low water pressure, high temperature setting, or limescale reducing flow. Try lower temperature.

Can I replace an electric shower myself?

Legally no - it's notifiable work requiring a qualified electrician. The electrical connection needs testing and certification.

Why is my shower weak but pressure fine at taps?

The shower's internal filter or solenoid may be blocked. Could also be spray plate limescale.

Should I get a power shower instead?

Power showers need a hot water supply and tank - different system entirely. Electric showers heat cold mains water directly.

Electric shower problems in Devon? Call Grant's Electrical Solutions on 01626 374 059 for expert diagnosis and repair.