Common Vaillant Boiler Problems & Repair Advice

Common Vaillant Boiler Problems & Repair Advice

Vaillant Repair Advice

More often than not, we can rely on our boilers to provide our homes with heating and hot water. It can be easy to almost forget they’re even in our homes. Until the morning you wake up, step into the shower and the hot water doesn’t arrive, which leads to the ice-cold realisation that your boiler has stopped working.

Rather than chaos descending upon the house, we’ve put together this guide that highlights some common boiler problems that can be resolved without the need for an engineer. Some faults will always need an engineer though, and if in doubt always contact an engineer, if that’s ever the case then you can get a free boiler repair quote with our service.

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Who are Vaillant?

With over 140 years of experience creating products for the heating market, Vaillant have gained a great reputation for performance, quality and reliability. Find out more about Vaillant and their full range of boilers on Boiler Guide.

Top 5 Vaillant Boiler Problems

  1. Leaking

    If your boiler is leaking then it’s likely to mean that an internal component has broken. Depending on where the leak is coming from, an engineer will need to be called out to investigate.

  2. Poor flow rate from taps

    Flow rate describes the rate at which water comes out of taps or shower heads, and a poor flow rate means that the flow of water is slow. If this is happening then you may need to change your open-vent heating system, raise the height of the tanks in your loft, or force water to specific outlets by fitting a pump.

  3. Pressure Release Valve dripping

    A PRV is an important safety feature of your boiler, that activates if the water pressure rises to a level that the boiler can’t handle. An engineer will be needed if you see any dripping and will probably have to recharge the expansion vessel. Should it keep dripping, the valve itself may need replacing.

  4. Radiators not heating up

    If you find that your radiators aren’t heating up or are only heating up at the bottom, you may need to bleed them. This is something you can carry out yourself and if you feel up to the task then our guide to bleeding radiators can take you through the process.

  5. Low pressure

    If the pressure of your boiler drops below a certain point then the boiler won’t start and can lead to your central heating system not functioning properly. It’s recommend to check your boiler’s pressure regularly, which can simply be done by taking a look at the built in pressure gauge, if it’s below 1 you may have an issue. Get to know more with our guide to low boiler pressure.

Which Boiler Issues Need an Engineer?

We’ve put together a list of the most common boiler symptoms, to give you an idea of what they might mean and whether you’ll be able to fix it yourself or need an engineer.

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Problem Possible Cause Do you need an engineer?
No heat or hot water Broken diaphragms and airlocks, failure of motorised valves, issues with the thermostat or low water levels Yes
Leaking and dripping Most common cause is a broken internal component but it will depend where the water is leaking from Yes
Banging, whistling or gurgling noises A common cause is air in the system, alternatively it could be that the water pressure is too low or it’s kettling Yes
Pilot light goes out Could be a broken thermocouple which is stopping the gas supply Yes
Losing pressure Could be a water leak in the system, the pressure relief valve needs replacing or due to recently bleeding radiators Only if there’s a leak
Frozen condensate pipe Your boiler will often display a fault code or warning notification Yes
Thermostat issues Thermostat may be turned off or not set to the correct settings (time etc.) Consider replacing
Kettling Limescale or sludge building up on your boiler’s heat exchanger Yes
Radiators not getting hot Sludge or air build up in the system or an unequal distribution of heat You will need to bleed the radiators which doesn’t require an engineer unless you don’t feel like carrying out the task yourself.
Boiler keeps switching itself off Could be low water pressure, a problem with the thermostat or a lack of water flow due to a closed valve, air or the pump not circulating the water in the system properly Yes

Error Codes

Vaillant boilers will display an error code when there’s a fault so if you’re seeing one then check our list of Vaillant error codes to find out what it means.

Should You Replace Your Vaillant Boiler Instead?

If you’ve had your vaillant boiler for some period of time then it’s worth considering a new one as you could be saving up to £305* a year in a detached home. Find out how much you could be saving depending on your current boiler rating and property with the table below.

House Type G (<70%) F (70-74%) E (74-78%) D (78-82%)
Semi-Detached £200 £140 £120 £120
Detached £305 £210 £180 £180
Detached Bungalow £155 £105 £90 £90
Mid terrace house £175 £120 £105 £105
Mid terrace house £95 £65 £55 £55

Who Should You Choose to Replace a Vaillant Boiler?

If you think a new boiler is the right way to go then the next big decision is choosing who to replace it. The easy part is knowing that no matter who you get to replace a boiler they must be Gas Safe registered. Now that we’ve got that part out of the way, your choice ultimately comes down to a local engineer or a national company.

Local engineers can offer a very competitive rate and as they tend to be just one man and his van, you’ll get a very personal service from the same person throughout your communications. It’s always a good idea to get a quote from more than 1 engineer to make sure you’re getting the best deal, we recommend getting up to 3.

While branded manufacturers may be slightly more on the expensive side, big brand protection is a huge bonus and they can provide extra service such as ongoing boiler cover.

Boiler Insurance and Ongoing Cover

Boiler insurance is well worth considering if your warranty period has come to an end. Boiler insurance can be taken out with your energy supplier but you’re under absolutely no obligation to do so. When comparing insurance, the best ones will include an annual service and safety inspection, so keep an eye out for them.

Vaillant Boiler Warranty

Vaillant boilers come with between 2-5 years of parts and labour warranty as standard but many models can go beyond this when installed by a Vaillant advance installer. To help you find out even more, we’ve put together a complete guide to Vaillant warranties.

To keep the warranty valid for the entire duration, you will need to arrange an annual Vaillant boiler service which will also help to keep your boiler running safely and efficiently for as long as possible.

If you need an engineer to take a look at you Vaillant boiler, then send us an enquiry to receive free quotes from trusted engineers near you.

*According to the latest figures from the Energy Saving Trust

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