Common Main Boiler Problems & Repair Advice

Common Main Boiler Problems & Repair Advice

Main Repair and Boiler problems Advice

Boilers are trusted to quietly get on with their job of providing heating and hot water, you might even forget they’re there. Until that one morning where step into a freezing cold shower and are hit by the ice-cold realisation that your ever-so faithful boiler has packed in.

Soon enough, everyone in the house will know that the boiler has stopped working and it could be easy for panic to flood your home but it doesn’t have to be that way. Some common boiler problems don’t even require an engineer but if you do need one then you can get free boiler repair quotes with our service.

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Who are Main?

With over 75 years of experience producing boilers, Main have gained a reputation for reliability with their affordable products. Find out more about Main and their full range of boilers here.

Top 5 Main Boiler Problems

  1. Low boiler pressure

    Checking a the pressure level of your boiler can 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.

  2. Kettling

    When limescale or sludge builds up on your boiler’s heat exchanger, they can restrict the flow of water, which then causes the water to steam and boil, hence the name kettling.

  3. No heating or hot water

    If your heating doesn’t have any heating or hot water then diaphragms and airlocks may be broken, there could also be issues with the thermostat, low water levels or failure of motorised valves. It’s a good idea to check if an issue with with the boiler pressure or your thermostat is causing the issue.

  4. Radiators not heating up

    If your radiators aren’t heating up or are only heating up at the bottom then they may need to be bled. 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. Leaking and dripping

    Most commonly, a leak will be caused by a broken internal component, such as a pump seal or pressure valve. If the leak is coming from the pressure valve, your boiler pressure might be too high. If it’s coming from the pump seal, it may have worn out and need replacing.

Which Boiler Issues Need an Engineer?

Some of the most common boiler problems don’t even need the expertise of an engineer, to help you resolve some faults we’ve put together the table below.

Need a boiler repair?



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 No, unless 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

Main Error Codes

When your Main boiler has a fault, an error code will display on the screen, normally an E followed by some numbers. To help you identify the fault matching the code, take a look at our list of Main error codes.

Should You Replace Your Main Boiler Instead?

If your Main boiler has been providing heating and hot water to your home for many years, you could be saving up to £305* a year in a detached home just by fitting a brand new boiler. Take a look at the table below to see how much you could be saving depending on your current boiler rating and property.

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 Main Boiler?

After deciding that you’d like a new boiler installed, you have to decide who you like to carry out the installation and your choice will come down to a local engineer or a national company.

Branded manufacturers may be slightly more expensive, they can provide extra services such as ongoing boiler cover. You’ll also have big brand protection which is a huge bonus.

Meanwhile, local engineers can offer very competitive rates and you’ll get a personal service 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.

Boiler Insurance and Ongoing Cover

If your boiler warranty has expired, boiler insurance could be something worth considering. When comparing insurance, the best ones will include an annual service and safety inspection, so make a note of them. Boiler insurance can be taken out with your energy supplier but isn’t compulsory. Look out for boiler insurance and cover that includes an annual service of your Main boiler.

Main Boiler Warranty

The standard warranty of Main boilers ranges from 3-5 years if you keep up with their terms and conditions, otherwise the warranty will be just 12 months. We’ve put together a complete guide to Main warranties so that you know exactly what to expect.

Send us an enquiry today to receive free quotes for a new boiler and find trusted engineers near you with our free service.

*According to the latest figures from the Energy Saving Trust

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