Most of the time we don't give a lot of thought to our boiler - we set a schedule for the heating to come on or a temperature for it to reach and it does the job. Only when the boiler isn't working do we realise how crucial it is. But what are the most typical reasons for a gas boiler to break down?
Dealing with a boiler breakdown
Before we start looking at the most common reasons for a boiler breakdown, a quick word of caution on the subject of gas boilers. Never try to fix one yourself even if you are sure you know what the problem is. Always contact a Gas Safe registered engineer to look at it and put right the problem. Not only is it a requirement it is also a safety issue - after all, gas is highly flammable and can cause poisoning. So always have an expert along to confirm your suspicions and deal with the problem.
Common reasons that a boiler breaks down
Boiler breakdowns are most common in the winter months as this is when the boiler is most required. It is often also when they have been inactive for a while and therefore problems can have occurred without the homeowner knowing about it. The sudden requirement for hot water and heating can cause a breakdown in the boiler and the uncomfortable position of being cold and without any hot water.
Old boiler problems
The most common reason for a boiler to break down is simply that it is getting on a bit and isn't working as fluently as it did in its younger years. There are two main reasons for this - corrosion and rust. Corrosion is the effect water has on metal over time and can lead to weaknesses in pipes or internal fixtures. Rust is produced by corrosion and depositing into the boiler and its systems, restricting the flow of water and causing other problems.
No hot water
If there's no hot water, then there's nothing for the boiler to pump around the radiators and to heat the home. So why does a boiler stop heating the water? There are lots of reasons for this problem and definitely one that an engineer will need to investigate to find the right answer.
One of the most common reasons is that there is a broken airlock or diaphragm, or that the motorised valves in the boiler have failed. All of these would stop the boiler working properly. The pressure within the boiler can also be an issue - lack of pressure means nothing to push the hot water around the system. Low water levels might mean a leak somewhere and that there isn't enough water in the system.
Thermostat isn't working
Another common issue comes from the thermostat. These send signals to the boiler that it needs to do something because the house isn't warm enough. If these signals aren't sent, then the boiler doesn't know it is required to do anything. Thermostat problems can be something as simple as the batteries have run out or that the thermostat is malfunctioning. Occasionally, the problem is that the boiler isn't receiving the message or acting on it.
Leaks or dripping pipes
Leaks can lead to low water pressure problems as mentioned in number 2 and can also lead to problems with dampness and even flooding the house. Dripping pipes are also a cause of boiler problems and can lead to bigger issues. If you have water escaping from your boiler or any of the associated pipes, you should get someone to look at it as soon as possible. A small leak might seem innocent enough but if the pipe was to burst, the damage can be catastrophic. And if it is hot water in the pipes, this could also be dangerous for anyone in the house.
Pilot light problems
The pilot light indicates that there is gas flowing into the boiler and that it is working correctly but if this goes out, it means there is a problem. Sometimes it could be that there is a broken thermocouple within the boiler - this is a device that measures the temperature of the boiler and stops is getting too hot. Other times the problem could simply be a build up on the pilot light causing it to malfunction.
Issues with the gas supply can also lead to pilot light problems. You can check your gas stopcock is okay and if you have gas to other appliances in the house then the problem might be more the boiler than the supply. If you ever smell gas, then use the gas emergency number straight away and get everyone out of the house.
Frozen condensate pipes
If you have a combi boiler, then the problem is sometimes the condensate pipes - these remove the waste steam and condensation from the boiler and are the cause of plumes of steam outside the house. If these don't work properly then the steam has nowhere to go and the boiler will shut down for safety reasons.
You can easily spot if these pipes are frozen or any other problems. They are visible from outside the house, usually near where the boiler is located. The pipe is normally white and around 2cm in diameter. It will have a pipe leading to the drain for water. Look for signs of damage or ice.
Conclusion
Breakdowns are possible with any piece of equipment regardless of the age. But with the boiler, it can help to have an annual service. This checks over these most common faults and other ones that reduce the risk of something going wrong during the winter, when you need the boiler the most.
A Gas Safe engineer can carry out a regular service for you and many of the utility companies such as British Gas offer policies to cover these costs if you don't want to pay when the service is due. You can search for one here, https://www.gassaferegister.co.uk/. These policies also cover if there is a breakdown with the boiler during the year too.
