The 11 Signs Your Boiler Needs Servicing

18 July 2023

Boilers are pretty robust these days, and you can expect an average one to last around 15 years. But that lifespan is dependent on them being well looked after. 

There are some sensitive instruments and controllers inside, which need to be calibrated to ensure safe, efficient running. And there are some workhorses, particularly the pump, that put in thousands of hours of operation every year and will inevitably wear down. 

That’s why you should have your boiler serviced once a year, starting 12 months after it was first installed. Indeed, your warranty will probably only apply if you have had it serviced annually. So for your safety, comfort and your bank balance, it’s definitely worth doing. 

But what if your boiler was serviced six months ago and you suspect it might need servicing? It’s possible that something went undetected during the service, or that something that was fine back then has broken down. 

Remember also that the service engineer will focus on the boiler, not the whole central heating system, so a problem could have only become apparent recently after bleeding in from elsewhere in the system. 

These are some of the things to look out for when considering whether to give the engineer a call.

1. Strange noises

If your boiler is making strange noises such as banging, whistling or gurgling, it could be a sign that it needs servicing. We’ve written another article about the specific sounds you might hear, and what a normal boiler should sound like. But basically, if your boiler is making sounds that it normally doesn’t, the chances are you’re getting a blockage in the heat exchanger or pipework, or a component is failing. A service should be able to quickly identify and fix the fault, especially if you’ve caught it early.

2. Carbon monoxide detector alerts

This is by far the most serious issue, as it represents a risk to the health of you and your family. Carbon monoxide detectors are like smoke alarms in that they shouldn’t be ignored. If yours is going off, there’s a very good chance it’s down to a fault with your boiler. That could mean a bad fuel air mix or a blockage in your flue. Check your exhaust outlet isn’t blocked with leaves or a bird’s nest, but just to be safe, please call out a qualified gas engineer.

3. Leaks

Any signs of water leakage around your boiler should not be ignored, as it could be evidence of a problem that needs to be addressed. Have a look at our article on leaks to get more information. Different types and locations of leak from the boiler itself or from around it can have very different causes. Engineers will recognise all the different types of leak and a service will remedy them.

4. Low water pressure

Low water pressure may be a sign that your boiler needs servicing. That can be down to a leak somewhere in the system (not necessarily in the boiler itself). It could also be caused by a faulty pump, or the gauge that reads the pressure might be faulty. If you have a combi boiler, the hot water pressure is largely determined by the external water supply, so that could be at fault too. In such cases, it might be worth switching to a different kind of boiler.

5. Pilot light issues

Does your boiler have a pilot light that is frequently flickering or going out? It could be a sign that it needs servicing. This is usually down to a blockage or damaged tube, but it’s absolutely vital for the operation of your boiler that it’s working well.

6. Lack of heat or hot water

If your boiler is not providing sufficient heat or hot water, no matter how high your thermostat or what temperature you have the hot water set to, something is wrong. This could be down to a problem with your pump or heat exchanger, or the electronics might be giving false readings.

7. Uneven heating

If there are areas of your home that are significantly colder than others, it could be a sign of a boiler problem that needs to be addressed. Water will naturally cool as it goes around the radiator system, but if it’s noticeable, it’s likely that it’s not reaching the desired temperature or it is being pumped too slowly.

8. Increased energy bills

Take a look at your last few years’ energy bills. Pay attention to the actual usage rather than the cost, as the price of gas can go up or down. You might have to submit your own readings, in which case it’s a good opportunity to check. If your usage has risen, it could be due to an inefficient boiler. Remember to compare your usage with the same time last year, i.e. don’t compare winter with summer, or February with May.

9. Slow heating

If your boiler takes longer than usual to heat up your home, it’s probably a sign that a component is on the verge of failing. It’s definitely worth getting someone in to look at it, even if the boiler does seem to be basically working.

10. Frequent breakdowns

Are you finding that your boiler keeps breaking down? Get a gas safe engineer to have a look at it. This can happen even if you’ve stuck to the annual service schedule. If your boiler is around 15 years old, or much older, it might unfortunately mean you need a new boiler. On the upside, you’ll get a more modern machine that is a lot more efficient to run. That’ll save you money every month, and you’ll be doing your bit for the environment.

11. Your calendar!

Finally, we’re back where we started – with your annual service. And that’s appropriate, because every boiler year should start with a friendly engineer popping round and making sure your boiler is safe and efficient. A well maintained boiler is much less likely to break down, and it will cost you a whole lot less in gas bills. Book your service today.