Facebook pixel
new boiler

Get a new boiler

Fixed price boilers, next day

See boiler prices
new air conditioning

Air Conditioning

Get a quote
new heat pump

Heat Pumps

Coming soon

new ev charger

EV Chargers

Get a quote
boiler servicing

Boiler Servicing

Get a quote

Last updated: 13th January, 2024


Why is My Boiler Not Working? iHeat's Expert Insights

Why is My Boiler Not Working? iHeat's Expert Insights

Key takeaways

  • Accurate problem identification is key to effective boiler repair.
  • Regular maintenance can prevent common boiler issues.
  • Professional help should be sought for complex or safety-related problems.

Maintaining a boiler in good working order is essential for its efficiency and longevity. Regular checks can help prevent disruptions, such as ensuring that the pressure settings are correct and there's no sludge build-up in the system.

Understanding why a boiler isn't working can often feel like a daunting task. Boilers are vital household appliances, providing hot water and central heating, and when they malfunction, it can be both inconvenient and uncomfortable. Many factors may contribute to a boiler not operating as it should. 

It could be something simple like a tripped fuse or power cut, or it might be more complex, like a frozen condensate pipe or gas supply issues. Accurately identifying and tackling these problems requires a certain level of knowledge and expertise.

Need a new boiler?

Get a quote in 60 seconds, fitted as fast as next day!
0% APR finance available.

Get a quote

Maintaining a boiler in good working order is essential for its efficiency and longevity. Regular checks can help prevent disruptions, such as ensuring that the pressure settings are correct and there's no sludge build-up in the system. 

However, when problems do occur, troubleshooting steps can be taken before needing to call in a Gas Safe registered engineer. While many issues can be resolved by homeowners, certain problems must be addressed by a professional to ensure safety and compliance with regulations.

Understanding Boiler Basics

To address boiler issues effectively, it's essential to have a grounding in the basic types of boilers and their components.

Types of Boilers: System, Combi, Heat-Only

System Boilers: These boilers require a cylinder for storing hot water but don't need a tank in the loft. They are particularly beneficial for homes with multiple bathrooms, as they can provide a constant supply of hot water to several taps at once.

Combi Boilers: Combi or combination boilers are the most common type in the UK, providing hot water on demand without the need for a cylinder or storage tank. This makes them a compact choice for smaller homes and flats.

Heat-Only Boilers: Also known as conventional boilers, they require a cold water storage tank, usually in the loft, and a hot water cylinder. They're suitable for homes with traditional heating and hot water systems.

Common Components

A boiler's functionality hinges on several key components:

  • Heat exchanger: This transfers heat from the gas jets to the water.

  • Burner: A vital part igniting the gas or oil.

  • Thermostat: It controls the temperature by regulating the burner.

  • Pump: Ensures water circulates through the boiler and the heating system.

  • Pressure relief valve: Maintains a safe boiler pressure by releasing excess.

  • Expansion vessel: Copes with the expanded water as it heats up.

Understanding these basics arms homeowners and technicians with the knowledge needed to troubleshoot issues effectively.

Diagnosing Common Problems

When a boiler malfunctions, pinpointing the issue is the first step to getting your system back in order. Accurate diagnosis can save time and money, and prevent minor problems from escalating.

No Hot Water or Heating

If they find themselves without hot water or heating, homeowners might be dealing with a range of causes. An extinguished pilot light, a malfunctioning thermostat, or low water levels could be at fault. They should check the boiler pressure as well, ensuring it's within the normal operating range.

  • Common Causes:

    • Failed components such as the motorised valves, diaphragm, or airlocks

    • Thermostat issues

    • Low water pressure

Leaks or Drips

Leaking boilers can stem from a variety of sources. Corrosion within the system or improperly fitted pipes often lead to drips. Sealant deterioration or pressure valve faults could also be the culprit. Immediate attention to leaks is essential, as water damage can escalate costs and down time.

  • Common Sources of Leaks:

    • Pressure valve failure

    • Pipe corrosion

    • Sealant wear

Unusual Noises

Boilers can become quite vocal when they're unhappy. Kettling, caused by limescale build-up, creates a sound similar to a kettle boiling. Air in the system or low water pressure may emit popping and whistling tones. Regular maintenance helps to keep the boiler silent and efficient.

  • Types of Noises and their Causes:

    • Banging: Air in the system

    • Whistling: Limescale or low pressure

    • Gurgling: Blocked water flow

Within each of these categories, boiler issues could be further diagnosed by isolating exact symptoms and cross-referencing the manufacturer's guidelines and error codes if available. Professional advice is invaluable when the solution isn't clear, ensuring safety and efficiency are prioritised.

Troubleshooting Guides

Ensuring your boiler functions effectively involves routine checks and understanding common issues that may arise. This section navigates through pivotal troubleshooting steps focusing on pressure issues, warning signals, and ignition problems.

Boiler Pressure Issues

Boiler pressure is critical for proper functioning. A pressure gauge reading that consistently falls below 1 bar indicates low boiler pressure, which hampers boiler operation. To alleviate this, one must repressurise the system by following the manufacturer's instructions, usually involving opening valves to allow water to refill the system. Conversely, excess pressure can also occur and may require releasing water from the radiators to stabilise.

Error Codes and Warning Lights

Modern boilers are equipped with diagnostic systems, prominently featuring error codes on their displays. These codes signal specific faults within the system, such as sensor failure or internal malfunctions. It’s helpful to consult the boiler manual or seek professional advice to accurately decode these error messages. For example, a flashing red light might indicate an immediate need for technical assistance.

Pilot Light and Flame Problems

The pilot light should emit a strong blue flame. If it's yellow or orange, this points towards incomplete combustion, a potentially dangerous issue. If the pilot light extinguishes frequently, it might signal a faulty thermocouple or a blocked pilot jet. Simple cleaning or a professional assessment might be necessary to address such flame-related pressure problems. It is important never to commence work on gas appliances unless one is a Gas Safe registered engineer.

When to Call a Gas Safe Engineer

If your boiler encounters issues, it's paramount to assess whether professional assistance is required. Gas Safe engineers are certified to manage and rectify boiler complications safely. Here are specific instances where their expertise is indispensable:

  • Carbon Monoxide Presence: Should you detect any signs of a carbon monoxide leak, such as headaches, dizziness, nausea, or the presence of a suspicious odour, it's critical to evacuate the premises and promptly contact a Gas Safe engineer.

  • Gas Leak Suspicion: Upon suspecting a gas leak, indicated by a distinct sulphuric smell or hissing sounds near gas lines, one must take immediate action to vacate the area and reach out to emergency services or a Gas Safe registered technician.

  • Boiler Flame Irregularities: An irregular flame, such as one that's yellow rather than crisp blue, signals incomplete combustion and potentially harmful emissions. An engineer's analysis is necessary.

  • Boiler Pressures Fluctuations: Fluctuating or consistently low pressure in your boiler system can hint at leaks or other serious issues that call for a professional's diagnostic expertise.

  • No Heating or Hot Water: Pervasive lack of heating or hot water, not due to simple control or power issues, may signify a deeper mechanical problem that demands an engineer's resolve.

  • Frequent Resets and Failures: A boiler necessitating frequent resets or failing to sustain operation is indicative of underlying faults only a certified engineer should investigate and mend.

Always remember that DIY repairs on a gas appliance can be highly dangerous and are illegal without proper certification. Prioritising safety, one should entrust boiler malfunctions to a Gas Safe registered professional, ensuring the durability of your heating system while safeguarding occupants' well-being.

Maintenance Tips

Keeping a boiler functioning at its best requires attention to regular servicing and preventive measures. Implementing these maintenance strategies can stave off unexpected breakdowns and extend the lifespan of your heating system.

Regular Boiler Service

Annual boiler service is essential for the well-being of your heating system. A certified engineer should inspect the boiler to ensure its components are in prime working order, addressing any wear and tear promptly. They will perform critical checks on the heat exchanger, burner, main injector, and safety devices. This is not merely a recommendation—it's a safety imperative.

Preventative Measures

Preventive measures include a variety of actions aimed at stopping problems before they start:

  • Install a Magnetic Filter: It traps any rust and debris from the system.

  • Use a Central Heating Inhibitor: It helps in reducing corrosion within the heating system.

  • Power Flush Your System: Recommended occasionally to clear out sludge that may have accumulated in the system.

  • Insulate Your Pipes: To prevent them from freezing during winter.

  • Bleed Your Radiators: This removes trapped air, allowing hot water to fill every part of the radiator, thus improving efficiency.

Routine maintenance and these proactive steps are the frontline measures that keep a boiler in robust condition, ready to provide warmth and hot water reliably. Remember, neglecting any minor concern today might lead to a significant boiler repair tomorrow.

New Boiler Costs

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

Boiler costs can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


Get a quote

System to combi conversion


Get a quote

New boiler install


Get a quote

Back boiler to a combi


Get a quote

System to system


Get a quote

Some location factors that can influence the price of your new boiler

You will be given a specific quote from the boiler installation company based on:

  • The type of home you have (i.e. terraced, semi-detached, etc.)

  • How many bedrooms you have

  • How many bathrooms you have

  • Your postcode and specific location

Get a quote

Frequently Asked Questions

How do I get my boiler to work again?

If your boiler isn't working, first ensure that the electrical supply is functioning correctly. Checking the fuse box for any tripped switches or blown fuses is an essential step.

Why would my boiler suddenly stop working?

Sudden stoppage can result from various issues such as a frozen condensate pipe, low water pressure, or lack of gas supply. Each cause requires a different approach to troubleshooting.

Why is my boiler not firing up?

A boiler might fail to ignite due to problems with the power supply, such as power cuts or electrical faults. Inspecting the power source is the initial step towards diagnosis.

What do you do when your boiler won't turn on?

When a boiler won't turn on, verifying the thermostat's settings and checking for any error codes displayed on the boiler can provide insight into the issue. Professional help may be necessary.

What is the most common boiler problem?

The most common boiler problem is low water pressure, which can be identified by checking the boiler's pressure gauge. Re-pressurising the system may resolve this issue.

What to do if your boiler isn't working?

If the boiler stops working, investigate simple factors including thermostat settings and pressure levels. If these don't remedy the situation, call in a certified engineer.

Do boilers have a reset button?

Boilers typically feature a reset button, which can be used to restart the system following a lockout. It's critical to consult the manufacturer's instructions before attempting a reset.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.