Electric Shower Not Getting Hot? Here’s Why (And How to Fix It)

A hot electric shower is something most of us take for granted — until it stops getting hot. When your shower starts spraying you with ice-cold water, figuring out what’s wrong and fixing the problem is a top priority.

Your electric shower may not be getting hot due to a lack of power supply caused by damaged fuses or switches, a malfunctioning heating element, or a build-up of solid minerals.

In this article, I’ll discuss the causes of your electric shower suddenly losing its capacity to heat water, and provide you with some simple do-it-your own fixes I’ll also tell you when the problem is too complex for a DIY fix and requires the help of a plumber. 

How Do Electric Showers Work?

Before I get into diagnosing and fixing your electric shower’s heating issue, I need to briefly explain how electric showers work so you can more easily troubleshoot and fix your shower.

Electric showers work the same way as electric toasters do — heat is produced by sending an electric current through a heating element.

The heating element is responsible for converting cold or tap water into hot water, which will be stored in a small tank to ensure a constant supply of hot water.

The exact method of temperature control depends on the sophistication of your shower.

In basic electric showers, turning the temperature dial on your shower changes the amount of water that flows past the heating element.

The more water that runs over the element, the hotter the water temperature.

A more complex shower will use a combination of thermostats, flow sensors, and pressure-balancing valves to control the temperature.

It may also use a water mixing tank to prevent sudden temperature changes when you move the temperature dial.

Now that you have a basic understanding of how electric showers work, let’s get into the troubleshooting.

Causes of Electric Shower Not Getting Hot

Electric showers have built-in safety measures designed to avoid dangerous problems such as short circuits and extremely high water temperature.

However, more often than not, a damaged or a malfunctioning safety measure is the cause of your shower not getting hot.

In addition, electric showers can also fail to provide hot water due to iron and limescale build-up in the filters, showerheads, and shower tubes.

These build-ups are caused by the presence of minerals in your tap water.

Let’s get into these in more detail below:

Malfunctioning Heating Element

As I mentioned, the heating element is responsible for heating the water that passes through your electric shower.

A malfunctioning heating element is the most likely reason your electric shower isn’t getting hot; heating elements can have a variety of potential issues, but they often simply stop working due to corrosion and old age.

Before testing the heating element, you’ll need to make sure that the water supply and power supply are both turned off.

You can do this by either turning off the isolation switch or a pull-over switch, depending on your shower model.

As an added safety precaution, turn off the breaker switch that powers your electric shower.

This will protect you from a dangerous short-circuit if your electric shower has faulty electric wiring.

How to Troubleshoot the Heating Element

1. After ensuring that no electricity is going into your shower, remove the cover of your shower.
2. You should be able to see a small heating tank under the cover. Inside this tank is the heating element (or elements) that you will be testing.
3. You will notice that the tank has two wire connections – blue and black. (The black color may be brown in some showers.)
4. Using your multimeter, connect the black probe with the blue wire and connect the red probe with the black/brown wire.
5. You’re checking the element for resistance, so your multimeter should be measuring in Ohms.
6. If the resistance level is between 11 and 18, then your heating element is functioning properly. If it reads a 1 or a 0, then the element is blown and you’ll need to replace the heating tank.

Malfunctioning Thermal Cutoff Switch

Another common reason for most electric showers failing to heat correctly is a broken or malfunctioning thermal cutoff switch.

More commonly known as TCO, thermal cutoff switches are safety switches designed to automatically shut off the shower if the water temperature is too high.

If your electric shower has a faulty TCO switch, it may be shutting down your electric shower and its heating capacity even if your water temperature is perfectly safe.

To test the TCO, you will have to use your multimeter and test the TCO switch’s continuity. Here’s how to do this:

How to Check Continuity of TCO Switch

1. Again, ensure that the water supply and power supply are cut off before starting the test.
2. Open your shower’s cover and locate the TCO. It should be on top of the heating tank.
3. Using your multimeter, attach each probe to one of the metal handles on top of the TCO switch.
4. If your multimeter continues beeping while the probes are connected, then the TCO switch is working correctly.
5. If the multimeter stops beeping, then you will have to replace the TCO switch.

Here’s a helpful video from The Shower Doctor that walks you step-by-step through this process:

Malfunctioning Shower Mixing Valve

As I mentioned above, more sophisticated showers will use a water mixing tank to blend hot and cold water, thereby preventing sudden temperature changes.

If your valve is not positioned correctly — or if it’s corroded and broken down — your water might be coming out colder than you’d like.

There’s no easy fix for this, as you’ll need to dismantle the shower fixtures. You’ll need to call a plumber to handle this problem.

Check for Mineral Build-Ups in Your Shower Head and Hose

If you’re not getting any water at all, the issue might be a mineral build-up in your shower head or hose.

According to the US Geological Survey, 90% of American households are running hard water, which is rich in solid minerals such as iron, calcium, and magnesium.

If left unchecked, these minerals will eventually accumulate and cause clogs in your pipes, faucets, and showers. 

Furthermore, if you have been using the shower for quite some time now, it is also very probable that grime, dirt, and other foreign materials have clogged the holes in your shower head and hose.

How to Check and Fix Clogged Showerheads

1. Make sure that the power supply and water supply are shut off.
2. You will need vinegar, a plastic bag, and a zip tie.
3. If your shower head is removable, remove it from the shower and inspect the nozzle for clogs.
4. Thoroughly clean the shower head. Make sure to poke the holes to remove the dirt, grime, and the other foreign substances stuck on your shower head.
5. Put a sizable amount of vinegar in the bag (enough to fully drown the shower head).
6. Put the showerhead in the bag; make sure that the head is fully immersed with the vinegar.
7. Zip tie the bag. Leave for 12 hours.
8. After 12 hours, wash with soap and reattach the showerhead.

Chris Hewitt

Chris is a Texas-based freelance writer who loves the outdoors and working in his garage. When he’s not enjoying the Texas sun, he can be found tinkering with all sorts of things in his workshop.