Is Your Electric Boiler Not Working?

Tony Hernandez|

Do you own an Ariston, Megaflow, Tempest, Tristore, Santon or OZO electric boiler?

This applies to you if your electric boiler isn’t working!

If your electric boiler is not working and you’ve got no running hot water or the water isn’t heating up, it might be an easy fix that doesn’t require a plumber. So, we’ve listed 6 easy checks and remedies you can make, to find out if your hot water unit is working correctly and to get it up and running again.

Of course, sometimes the easiest and quickest way is to contact us out and we can have you up and running in no time.

Short on time?

The quickest and stress-free way to get your electric boiler working again is to call us out. Our vans carry many common spare parts, so we can usually get your electric boiler working in the same visit. Contact us for a no-obligation phone consultation/quote. We cover North London, West London, Watford, Herts, Middx, and nearby locations. These common faults can happen at any time and, in some cases, can also stop your electric boiler from working correctly.If not resolved swiftly, then some of these problems can lead to severe damage (including safety issues) and, in certain circumstances, may require replacing your electric boiler for a new model.Even if the severity of these issues doesn’t result in electric boiler replacement, if left unspotted, these problems can also cost you a lot of money in water and electric bills, especially if you are on a water meter.

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Electric Boiler Not Working?

6 problems, symptoms and cures

Problem 1: Water dripping into Tundish

Check the Tundish to see if water is discharging. If water is discharging, this means the safety valve has opened due to too much pressure in the unit or too much heat.

Remedy: Try twisting the black or red cap on the temperature pressure relief valve to try to reseat the valve. If water doesn't stop discharging, you will then need to turn the water off and contact an engineer.

Problem 2: Water Discharging at Tundish at Fast Rate

Check the boiler expansion vessel (normally installed on the wall beside the boiler). Do this by tapping the side of the vessel with a spanner. If the vessel makes a sound like it's full of air (dull) or full of water, then this means the expansion vessel needs to be replaced.

Remedy: You will need to turn the water off and then contact our engineer to replace parts to get your vessel working properly again.

Problem 3: No Hot Water

Check that the power supply and the programmers (thermostats and timers) are on and calling for heat. If the power and the programmer are on and there is still no heat, you'll possibly need to replace the elements and thermostats.

Remedy: You will need to turn the water off and then contact us to replace parts, drain the boiler down, and replace elements and thermostats.

Problem 4: No Flow of Hot Water

Check that the service valve has not been switched off or is partially closed.

Remedy: Open the service valve fully manually. If this does not work, it then means you may need to replace the valve for new.

Problem 5: Not Enough Hot Water

Check that unit is heating up and that the elements are working.

Remedy: If the elements are not working, then you'll need to replace them. It's also possible that the unit needs to be upgraded for a bigger unit.

Problem 6: Water Pressure Too High

Check that this is the same on all taps throughout the property and that there are no leaks.

Remedy: If this is the same on all taps, then the combination valves pressure reducer may need replacing.

Electric Boiler Still Not Working?

If your electric boiler is not working and you would like your electric boiler unit serviced or inspected by our professional engineers, then please contact us today for an appointment that suits you.

Categories: How To, Water
Last updated: 22/08/2025

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About the Author

Tony Hernandez - Founder of Advanced Heating & Plumbing
Gas SafeOFTEC

28 Years Experience

Tony Hernandez

Founder of Advanced Heating & Plumbing

With 28 years in the trade since 1998, Tony is a highly respected heating and plumbing authority serving Watford, Hertfordshire, London, and Middlesex. Gas Safe and OFTEC registered with expertise in gas, oil, and electrical systems.

View all articles by Tony