13 Most Common Boiler Problems and How to Fix Them

Boilers are essential to our homes and keep us warm and cosy throughout the winter. Requiring just a little maintenance annually, the boiler provides our homes with hot water and heating for years. But we don’t consider the fact that it is a complex machine with numerous components and parts that work in sync. If any of these parts get faulty, this causes boiler problems.

Sometimes, you will be able to inspect the boiler issues; sometimes, you can’t, which causes the problem to build up and make it more severe. Due to this, many heating experts suggest getting an annual boiler service to inspect these problems early before they can damage your boiler severely.

But there is no need to worry, as I will discuss the common boiler problems in this blog. Also, I will tell you how to inspect the boiler faults and the necessary actions to take. So, make sure you read this blog till the end.

13 Common Boiler Issues

1- No power to your boiler

One common boiler problem many people face is no power to the boiler. This happens in winter as the demand for hot water and heating increases, which puts an extended load on your boiler.

Reason

Your boiler is not turning itself on, mainly due to electrical problems. This means that you will need expert help to get this problem solved.

Necessary actions to take

Certified professionals should handle the problems related to electrical issues, as mentioned above. However, before you contact an engineer, you can perform the following basic checks yourself:

• Check your home’s electrical supply to ensure that other appliances are powering up and that the problem only lies with your boiler.
• Check for a blown fuse. The reason is that, just like other electrically operated appliances have fuses, your boiler has them too. What happens is that when the electrical components get faulty, it causes a power surge, causing the fuse to break the circuit and protecting your boiler from further damage. Although your boiler is covered, to turn it on, you must replace the blown fuse.
• The last check you must do is check for a tripped RCD (residual current device).

Note:

If you do not feel comfortable performing the above-suggested checks, then you should not risk your safety and contact a certified professional immediately.

2- Low boiler pressure

Low boiler pressure is another boiler issue that impacts the optimal efficiency of your boiler. A boiler operates at an optimal pressure of 1-1.5 bars on your boiler’s pressure gauge. If it falls below that, your boiler might lock itself out and display a low-pressure error fault code.

Reason

The reasons behind your boiler losing pressure are the following:

• Internal Leakage
• Bleeding out your radiators
• External leak to appliances including radiators
• Internal heat exchanger
• Incorrectly charged / sized expansion vessel

Necessary actions to take

If you suspect a leaking boiler, then you should immediately contact a certified professional however to be assured that the problem is solely related to low boiler pressure then do the following checks:

• Check your boiler filter. If it is clogged, try giving it a clean or consider replacing it.
• Make sure your boiler is not oversized, as a large boiler requires a lot of pressure, and if there is little demand in your home for heating and hot water, consider replacing your boiler with a smaller-sized boiler as it will save you a lot of money on your energy bills.
• Get an annual boiler service to ensure no buildup of corrosion within the system.

If the above-suggested steps do not solve the problem, damaged internal components might be the cause. In that case, only a certified professional will be able to help you.

3- No heating or hot water

If you are facing a situation where your boiler is in a lockout, providing no heating or hot water, then issues can be multiple.

Reasons

No heating or hot water from your boiler could be due to low boiler pressure, faulty components, including the diverter valve, and faulty pilot lights.

Necessary action to take

First, start with the basics! Check the boiler pressure and make sure the pressure ratings lie between 1 and 1.5 bars. If not, then re-pressurise your boiler with the help of a boiler filling loop.

If there is no pressure problem, check for a frozen condensate pipe and defrost it by pouring hot water onto it. If both points mentioned don’t help, the problem might be with the internal components of your boiler. You must contact a heating engineer and let him deal with the situation.

4- The boiler is making strange noises

A common sign that indicates a problem with your boiler is when it starts to make strange noises. Make sure to distinguish noises from the operating sound of your boiler. In general, the boiler will make a noise during its operation. You should be concerned about whistling, dripping, and tapping noises.

Reasons

If you hear a whistling-like sound coming out of your boiler, the reason is a buildup of limescale on the heat exchanger, causing it to overheat and make a kettling, tapping or whistling noise. If you hear a dripping noise coming out of your boiler, the issue is related to potential leaks within your system.

Necessary action to take

• You will need to get a central heating power flush to solve the issue related to the limescale buildup on the heat exchange. Also, you can install magnetic filters to prevent future limescale buildup.
• Contact a gas-safe engineer to re-tighten the loose parts causing the tapping noise related to poor installation.
• Lastly, you must contact a certified professional to inspect the problem and take corrective action for the dripping noise as it indicates potential leakage within the system. Although sometimes the leakage issue can persist due to your boiler getting old, in that case, you should consider a new boiler replacement.

5- Heating but no hot water

Many homeowners often face a common situation with their boiler where it heats but does not provide hot water. There is no need to worry about that, as you are not the only one.

Reasons

Low boiler pressure, incorrect thermostat settings, and broken diverter valves can cause hot water issues without affecting heating.  For more details, please read our blog: My central heating works, but there is no hot water.

Necessary actions to take

• Check your essential utilities, including gas, water, and electrical, and ensure they have no issues or problems.
• Check your boiler controls to ensure the correct setting on the boiler and thermostat.
• Check for frozen condensate pipes and defrost them by pouring hot water over them.

Boiler Insurance You Can Trust

Get boiler breakdown and landlord cover including free annual boiler service.

Choose your policy type

Get Boiler Cover Get Landlord Cover

6- The boiler is not responding to the thermostat

In modern times, many people use thermostats to set heating schedules for their boilers. By doing so, people save energy, as they only get heating when they are at home. But with convenience comes the potential for problems. Your boiler needs to follow the schedule set on your thermostat to avoid the common problem of not responding to it.

Reason

The reason behind this problem is not your boiler but your thermostat, as the thermostat might have gotten faulty with the passing time, or by mistake, the setting got changed, or the batteries might have drained.

Necessary actions to take.

• Firstly, if your thermostat is old or has worn down, it is time to replace it.
• Consult manufacturer’s literature for pairing instructions.
• Secondly, ensure the settings are adjusted to your preferred temperature.
• Lastly, check the batteries. The issue might be simple, and you only need to get new batteries.

Read more about why the boiler is not responding to the thermostat.

7- The pilot light keeps blowing out

Older boilers without electric ignition systems require being switched on for a while to ignite the fuel within the combustion chamber.  The pilot light charges the ignition. If the pilot light is turning itself off, then it means that the boiler will not be ignited, resulting in no heating or hot water.

Reasons

Carbon deposits that build up over time on the pilot light may be causing it to malfunction. Another reason could be related to drafts getting into your boiler and blowing out the flame. A faulty thermocouple could be switching off the gas supply.

Necessary actions to take.

It is recommended that you contact a gas-safe register engineer to solve the problem with the pilot light, which is a component linked to the gas supply. However, to be sure that the issue is with the pilot light, read our blog, “My Boiler Pilot Light Keeps Blowing Out,” and try out the steps mentioned in the blog.

8- Boiler Leaks

A leaking boiler is a problem that you should pay immediate attention to. High boiler pressure or holes in the pipework might be causing the issue, which may not be severe. However, sometimes, on inspection, the problem can prove to be extreme, related to faulty internal components, corrosion buildup, and a faulty heat exchanger, which can lead to heavy damage to your boiler, resulting in a boiler replacement. So, as soon as you inspect a leakage in your boiler, contact a gas-safe engineer immediately.

Reasons

Now you know the significance of a boiler leakage, but it is also essential to know about the reasons behind it, which are the following:

• Too much pressure
• Corrosion can occur in pipe fittings.
• Improper installation
• Faulty heat exchanger
• Internal Leakage
• Corrosion and general wear

To learn more about these reasons in detail, read our blog, Why Is My Boiler Leaking Water?

Boiler Repair

Book your boiler repair service online and save time and effort. Our certified engineer will provide you with hassle-free assistance.

Book a Boiler Repair

Necessary actions to take.

Apart from pressure-related problems, you should contact a Gas Safe registered engineer and let him inspect the problem for all the above reasons. If the problem is solely related to high pressure, then all you need to do is relieve some pressure by bleeding out your radiators and then repressurize them with the help of a boiler filling loop.

9- Faulty Radiators

Faulty radiators are another common issue not directly related to your boiler. What happens is that although your boiler is operating, delicate issues in the radiator, i.e., the radiator getting cold at the bottom, cause inadequate heat distribution around your home.

Reasons

The reason behind radiators getting faulty can be related to either an air lock or the buildup of sludge over time.

Necessary actions to take

To remove the airlock from your radiators, you need to bleed it out. To learn how to bleed out your radiators, read our detailed blog, How to Bleed a Radiator. If the bleeding doesn’t help, the reason might be related to the buildup of sludge. You will need to clean your system through a chemical flush or a central heating power flush.

10- Frozen Condensate Pipe

Frozen condensate pipe is an integral part of your boiler that helps remove the acidic water from your boiler to the outside. In winter, the freezing temperatures cause the boiler to halt its operations and display an error code.

Reasons

When your condensate pipe is located outside your home in winter, what happens is that, due to low temperatures, it gets frozen.

Necessary actions to take.

The frozen condensate pipe problem is simple and does not require the assistance of a certified professional. All you need to do is defrost the frozen condensate pipe by pouring hot water onto it; for more details, read our blog: How to defrost the frozen condensate pipe.

Important Disclaimer

Please remember that while this blog provides you with basic knowledge and troubleshooting tips for common boiler problems, your safety should always be your top priority. If you encounter any complex issues, gas-related problems, or situations that are beyond your comfort level, do not hesitate to seek assistance from a qualified professional.

11. Boiler Lockout

A boiler lockout occurs when the system shuts itself off as a safety measure due to a detected issue.

Reasons

This could be triggered by various factors, such as low water pressure, a faulty pump, or problems with the fuel supply (such as a blocked gas line).

Additionally, sensor faults, power supply interruptions, or overheating can cause the boiler to lock out.

Necessary Actions to Take

When a boiler goes into lockout, the first step is to reset the system using the reset button, following the manufacturer’s instructions. Check for any visible error codes on the boiler’s display, indicating the issue’s root cause.

If it’s a pressure-related problem, topping up the water pressure may resolve the issue. In cases where the issue is more complex, such as a faulty component or fuel supply problem, you should call a qualified heating engineer to diagnose and fix the problem.

Preventive Measures

To prevent lockout issues, it’s crucial to stay ahead with regular boiler maintenance. Schedule an annual service performed by a certified engineer to keep your system in top condition.

Keep an eye on water pressure levels and ensure the fuel supply, especially gas lines, is clear and functioning.

Address minor issues, such as noises or leaks, before they escalate into more significant problems that can trigger a lockout.

12. Boiler Breakdown

A boiler breakdown can occur due to several underlying causes, such as ageing components, wear and tear, or poor maintenance.

Reasons

Common issues leading to breakdowns include a malfunctioning pump, problems with the fan or thermostat, blocked heat exchangers, or an ignition failure.

Corrosion, electrical faults, or airlocks in the system may also contribute to a boiler breakdown.

Necessary Actions to Take

If your boiler breaks down, remember that safety comes first. Check whether there’s power or a tripped circuit breaker. Check the boiler’s pressure, reset the system, and review any fault codes displayed.

If there is no improvement, it’s essential to call a Gas Safe registered engineer to conduct a full inspection and repair the problem.

Avoid DIY repairs, especially with gas appliances, as this can be dangerous. Professional help ensures your safety and the proper functioning of your system.

Preventive Measures

Annual servicing is crucial in avoiding unexpected breakdowns. Regularly check for minor issues like strange noises, pressure changes, or leaks and address them early.

This proactive approach can help prevent these minor issues from escalating into more significant problems that can lead to a breakdown.

Ensuring proper ventilation around the boiler and maintaining the recommended operating temperature also helps extend the system’s lifespan.

13. Faulty Diverter Valve

A faulty diverter valve can prevent your boiler from properly switching between heating and hot water modes.

Reasons

Over time, this valve can become jammed, corrupted, or fail due to a mechanical fault. This can result in inconsistent hot water supply or heating issues.

Necessary Actions to Take

If you suspect a faulty diverter valve, call a qualified engineer to inspect and replace the valve if necessary. Temporary solutions like resetting the boiler may work, but a permanent fix requires valve replacement.

An engineer will also assess whether the issue is due to debris or limescale buildup restricting movement.

Preventive Measures

Regular boiler maintenance is essential to prevent diverter valve issues. In areas with hard water, a water softener may be recommended to reduce limescale buildup.

During the annual service, have your engineer check the condition of the valve and replace it before it fails.

Possible preventive measures that you can take.

• Get a boiler cover, including coverage for boiler breakdowns and the central heating system. If you decide to upgrade your boiler cover to a complete home care policy, you will also get covered for plumbing, drainage, home electrics and home security.
• Get an annual boiler service to keep it running optimally; also, check before buying a boiler cover policy, as many policies include an annual boiler.
• Monitor the pipework closely; if you notice any leaks, reach out to a professional for prompt assistance.
• Set a heating schedule on your thermostat to get heating when needed, minimising energy waste and prolonging effective heating.
• Keep your boiler running for a few hours to warm up the system, especially in the winter.
• As time passes, air becomes trapped in your radiators, causing cold spots that result in improper heat distribution throughout your home.
• If needed, get a central heating system to fully clean the system and install magnetic filters to prevent future buildup of sludge and debris within your central heating system.

Need Help? Contact 24|7 Home Rescue

If you need any help or assistance regarding the above-mentioned problem, feel free to contact us at 0345 3192 247, and one of our representatives will assist you on the call and guide you through it so you can take the correct action.

Also, if you want to cover your boiler to save money on damage repairs, look at our multiple boiler cover options and choose the one that best suits your needs. And if you don’t have a boiler cover in place and facing with a boiler breakdown then we also offer one-off boiler repair.

Hassle-Free Boiler Installation

Get your new boiler installed today and save money on your heating bills with an new energy efficient boiler.

Get a New Boiler