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Last updated: 13th May, 2024


Broken Boiler - Can I Fix DIY? (UK Expert Advice)

Broken Boiler - Can I Fix DIY? (UK Expert Advice)

Key takeaways

  • Recognising boiler issues early can prevent more significant problems.
  • Safety measures are crucial; some repairs are better left to professionals.
  • Regular maintenance and understanding when to consult an expert can prolong the life of a boiler.

Safety is paramount when dealing with a broken boiler, as incorrect handling can present serious risks, including gas leaks, carbon monoxide poisoning, and water damage.

When a boiler breaks down, it's not just an inconvenience; it can bring a household to a standstill, especially during the colder months when heating and hot water are essential.

Before embarking on any repair, it's important to recognise the signs of a malfunctioning boiler. These can vary from strange noises and leaks to a complete lack of heat output. Once identified, homeowners face the critical decision of whether to attempt a DIY fix or call in the professionals.

Safety is paramount when dealing with a broken boiler, as incorrect handling can present serious risks, including gas leaks, carbon monoxide poisoning, and water damage. Some issues, like resetting the boiler or bleeding radiators, may be within the realm of competent DIY enthusiasts.

However, more complex problems often require the expertise of Gas Safe registered engineers. Homeowners must also weigh the long-term solutions against the immediate cost considerations and the potential for future breakdowns, making informed decisions to ensure the safety and efficiency of their heating systems.

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Recognising the Signs of a Broken Boiler-

Identifying a malfunctioning boiler is pivotal to maintaining a safe and comfortable home. The following signs are strong indicators that something isn't working correctly within your boiler system.

No Hot Water or Heating

A clear sign of a broken boiler is the absence of hot water or heating. Should taps run cold or radiators remain unheated despite the thermostat being set correctly, the boiler's functionality must be questioned.

Unusual Noises from the Boiler

Boilers often make low-level noises as part of their normal operation; however, when sounds such as banging, kettling, or clunking emerge, these are atypical. Such noises may point to limescale build-up or a fault within the internal components.

Leaks and Drips

The presence of water around the boiler suggests a leak. Moisture can originate from a variety of sources within the unit, including seals or valves, and requires immediate attention to avert further damage.

Boiler Pressure Issues

Optimal boiler operation occurs within a pressure range of 1.0 - 1.5 bar. Deviations from this – either a low-pressure reading or frequent drops in pressure – serve as a warning of pressure issues. It's integral to consult the manufacturer's manual for specific guidance on this.

Error Codes on Display

Modern boilers typically feature a digital display that presents error codes when faults are detected. These codes are boiler-specific and referencing the manual or a professional can provide insight into the underlying issue necessitating repair or replacement.

Assessing the Boiler Issue

When a boiler malfunctions, identifying the root of the problem is the first step toward resolution. Below are some specific checks a homeowner can perform to assess common boiler issues.

Pilot Light and Ignition Check

One should first inspect the pilot light. If it's out, this may indicate an issue with the ignition system. To check the pilot light, remove the boiler's cover following the manufacturer's instructions and look for the small flame. If absent or intermittent, the ignition might need professional attention.

Thermostat Functionality

The thermostat should be the next focus point. One must ensure that it is turned on and set above room temperature. If the heating does not engage, this suggests a possible thermostat malfunction or a miscommunication between the device and the boiler.

Central Heating and Radiator Inspection

Lastly, assess the performance of the central heating and radiators. Ensure all radiator valves are open. If some radiators are cold while others are hot, this uneven distribution could indicate air trapped in the system or a potential blockage affecting water flow.

Safety Measures and Precautions

Safety around boilers is paramount, and taking the correct precautions can prevent perilous situations. Homeowners must be vigilant for signs of gas leaks and carbon monoxide poisoning, and understand when to call for professional help from Gas Safe registered engineers.

Identifying Gas Leaks

Gas leaks, if undetected, pose a dangerous risk within the home. Indicators of a gas leak include a sulphurous smell akin to rotten eggs, a hissing sound near gas lines, or an unexplained increase in gas bills. If a gas leak is suspected:

  • Do not ignite any flames or operate electrical switches.

  • Do immediately open windows to ventilate the area.

  • Do shut off the gas supply if safe to do so and evacuate the premises.

Carbon Monoxide Poisoning Symptoms

Carbon monoxide is a deadly and invisible threat, as it is odourless and colourless. Poisoning symptoms often mirror those of the flu and include dizziness, shortness of breath, nausea, and stomach pain. Long-term exposure may lead to confusion or even loss of consciousness. Homeowners should ensure they:

  • Install carbon monoxide detectors near the boiler and check them regularly.

  • Regularly service the boiler by a Gas Safe registered engineer to reduce risks.

When to Contact Gas Emergency Service

In the event of suspected gas leaks or carbon monoxide symptoms, one must contact the Gas Emergency Service immediately. Important steps include:

  • Call the emergency number: 0800 111 999 in the UK.

  • Avoid causing any potential sparks that could ignite gas.

  • Do not re-enter the property until it is declared safe by the emergency service team or a Gas Safe registered engineer.

Remember, when it comes to potential gas leaks and carbon monoxide issues, always err on the side of caution. It's imperative to involve professionals who are qualified and equipped to handle such dangerous situations safely.

DIY Quick Fixes and Maintenance-

Homeowners may often tackle certain boiler issues without the immediate help of a professional. This section outlines a few quick self-help measures and vital maintenance routines to keep their boiler in optimum condition.

Resetting the Boiler

At times, boilers may simply need a reset to resume normal operation. Locate the reset button, typically found on the boiler's front panel. Press and hold this button for about 10 seconds. If the boiler does not reactivate, consult the manufacturer’s manual for specific instructions.

Repressurising the Boiler

If the boiler pressure is too low, functioning may be impaired. Boiler pressure should generally sit between 1 and 2 bars. To repressurise, turn off the boiler and locate the filling loop, usually positioned underneath the unit. Carefully open the valves to allow water in, watching the pressure gauge increase to the recommended level, then close the valves.

Thawing Frozen Condensate Pipes

During cold spells, frozen condensate pipes may cause the boiler to fail. To remedy this, apply warm (not boiling) water to the pipe or use a hot water bottle until the ice melts. It's imperative not to use a direct flame or boiling water, as this could damage the pipes.

Boiler Maintenance Tips

Routine boiler maintenance is vital for long-term boiler health:

  • Regular Checks: Observing pressure levels and looking for visible signs of leaks or damage can pre-empt issues.

  • Annual Service: Have a Gas Safe registered engineer conduct an annual service to ensure safety and efficiency.

  • Bleeding Radiators: This helps in removing air trapped in the system, which may cause cold spots.

Implementing these measures greatly contributes to the lifespan and efficiency of a boiler, reducing the need for emergency repair.

Professional Repair and When to Hire an Expert

Hiring a professional heating engineer can be pivotal for ensuring the safety and efficacy of boiler repairs. Knowing when to engage an expert helps homeowners navigate through boiler issues with confidence.

Gas Safe Registered Engineers

It is compulsory for any engineer working on gas boilers to be Gas Safe registered. This certification is a legal requirement in the UK, designed to protect homeowners from the dangers of improper gas work. When a boiler malfunction occurs, one should immediately seek a professional bearing this crucial accreditation.

  • Checklist for hiring a Gas Safe registered engineer:

    • Verify their Gas Safe ID card upon visitation.

    • Ensure their Gas Safe registration covers the type of work required.

    • Look up the engineer or company on the Gas Safe Register's official website for authenticity.

Obtaining Repair Quotes

Before any repair work begins, it is recommended to acquire multiple quotes from different engineers or companies. This allows for a clear understanding of the cost of repairs and helps prevent overcharging.

Table: Indicative Repair Costs


Minor Repair Cost (£)

Major Repair Cost (£)

Faulty Thermostat

70 - 150


Replacing a Valve

140 - 250



100 - 200

400 - 600

Comprehensive Service

70 - 120


Please note these values are estimates and may vary based on location and the engineer's assessment.

Boiler Repair Complications

Boiler repairs can be fraught with complications, varying from minor issues to those necessitating a complete system overhaul. Instances when complications arise often signal the need for a skilled heating engineer.

  • Examples of complications necessitating expert intervention:

    • Persistent breakdowns despite multiple repairs.

    • Leaks involving gas or harmful by-products like carbon monoxide.

    • The need for diagnostic checks using specialised equipment.

Long-Term Solutions

When a boiler breaks down, the decision-making process should focus on durability and cost-effectiveness. Long-term solutions revolve around selecting a new boiler, exploring insurance cover options, and understanding the advantages of extended warranties.

Deciding on a Replacement Boiler

Choosing a new boiler can be crucial for both energy efficiency and home comfort. Homeowners should seek models with higher energy ratings, ideally A-rated boilers, which can significantly reduce energy bills. It is essential to compare various types and sizes of boilers, like combi or system boilers, and consider how they fit one’s home heating requirements. Newer models also come equipped with advanced features, offering more precise control over heating and contributing to long-term savings.

  • Compatibility: Ensure the new boiler is compatible with your current heating system.

  • Capacity: Select a size adequate for your home's need - neither too large nor too small.

  • Efficiency: Aim for models with high efficiency to reduce both carbon footprint and bills.

Understanding Boiler Cover Options

Boiler cover provides peace of mind with protection against unexpected breakdowns and costly repairs. Policies typically cover the cost of parts, labour, and sometimes even replacement if a boiler is beyond repair. To make an informed decision, one should scrutinise the terms and conditions, specifically clauses related to call-out fees, excess charges, and coverage limits. Boiler cover plans vary, with some including annual servicing which helps maintain the boiler’s efficiency and safety.

  • Inclusions: Look for policies covering a wide range of issues, including emergencies.

  • Exclusions: Be aware of what is not covered, such as pre-existing conditions.

  • Excess: Decide on an affordable excess, which is the amount paid upfront on any claim.

Extended Warranty Benefits

An extended warranty can supplement standard manufacturer guarantees, extending the period during which homeowners are protected against defects or malfunctions. Warranties often vary from one to several years and can be transferable should the property change hands. They may increase the initial outlay but offer savings and convenience in the long run by mitigating the cost of repairs or a replacement boiler. Homeowners should also look at the provider's reputation - a warranty is only as good as the company behind it.

  • Duration: Longer warranty periods provide more prolonged peace of mind.

  • Transferability: Check if the warranty can pass on to new homeowners.

  • Cost-Benefit: Evaluate the potential savings against the initial cost of the extended warranty.

Cost Considerations

When addressing the costs of a broken boiler, homeowners must weigh immediate expenses against the impact on long-term energy bills and consider the potential benefits of upgrading to energy-efficient solutions.

Energy Bills Impact

A malfunctioning boiler can significantly increase energy bills due to inefficiency. When a boiler struggles to produce heat, it often consumes more fuel or electricity in the process. Inefficient heating systems may also lead to uneven heating, prompting individuals to turn up thermostats, which further elevates energy consumption. The absence of hot water or adequate heating intensifies the urge to seek immediate, and sometimes costly, repairs rather than more economical, long-term fixes.

Investing in Energy-Efficient Solutions

Investing in an energy-efficient boiler can lead to substantial savings on future energy bills. While the upfront cost might be steeper compared to standard repairs, the long-term savings are considerable. An energy-efficient heating system operates more effectively, thus reducing the energy required to heat the home and provide hot water. Furthermore, this investment not only cuts down on regular energy expenditure but also bolsters the property's value and aligns with eco-friendly practices.

Preventive Measures

Preventing boiler breakdown involves proactive measures and regular maintenance. By carefully maintaining the central heating system and ensuring proper insulation techniques, homeowners can mitigate boiler problems and extend the lifespan of their equipment.

Regular Boiler Servicing

Having a boiler serviced annually by a qualified engineer is paramount. During a service, the engineer will check the boiler for issues such as a broken thermostat, wear and tear on parts, and any blockages affecting the flow temperature. Boiler maintenance includes cleaning key components and adjusting them to guarantee efficient operation. A well-maintained boiler is less likely to fail prematurely and ensures that central heating systems run effectively.

  • Checklist for Boiler Servicing:

    • Examination of boiler controls

    • Inspection for gas leaks or corrosion

    • Assessment of the boiler's internal components

    • Test of the boiler's performance and safety mechanisms

Home Insulation Techniques

Effective insulating of a home is a critical step in alleviating the workload on a boiler. When a house is poorly insulated, boilers must work harder to maintain desired temperatures, which can lead to increased wear and thermal stress. Insulating can take various forms, from cavity wall insulation to floor and loft insulation. Ensuring that the property retains heat effectively reduces the demand on the boiler and can lead to significant energy savings.

  • Insulation Strategies:

    • Loft Insulation: Laying down insulating material in the loft prevents heat from rising and escaping.

    • Wall Insulation: Filling wall cavities with insulating materials keeps warmth inside.

    • Double Glazing: Upgrading to double-glazed windows reduces heat loss and provides better acoustic insulation.

    • Draught-proofing: Sealing gaps around doors and windows prevents cold air from entering.

Implementing these preventive strategies is crucial for the longevity of a boiler and the efficiency of a home's heating. They assist in maintaining a consistent flow temperature and prevent undue strain on boiler components, which could otherwise lead to unexpected failures.


At iHeat all of our subcontracted engineers are Gas Safe registered and can service your boiler swiftly and safely. Prices of an expert boiler service with iHeat start from £99.These figures might fluctuate regionally and can also depend on the specific type of boiler you own, such as a combi, gas, or oil boiler. 

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When dealing with a broken boiler, it's important for UK residents to understand the legal responsibilities outlined in the Landlord and Tenant Act 1985, as well as the nuances of their boiler cover and insurance policies.

Understanding the Landlord and Tenant Act

Under the Landlord and Tenant Act 1985, landlords are obliged to keep the heating and hot water systems in good repair. This includes boilers as essential components. Tenants experiencing boiler issues should first check their tenancy agreement, as it may further clarify the landlord's responsibilities. If the agreement states that the landlord must repair the boiler within a certain timeframe, tenants have the right to enforce this.

  • Section 11 of the Act specifies that:

    • Landlords must ensure the boiler is safe to use and properly maintained.

    • Any gas supply problem must be addressed promptly to prevent health risks.

However, tenants should note that if the damage is due to their own negligence, they might be accountable for the associated repair costs.

Boiler Cover and Insurance Policies

Boiler cover is a type of insurance policy designed specifically to protect against the costs of repair and maintenance of a boiler. These policies vary widely:

  • Standard Cover often includes:

  • Comprehensive Plans may cover wider problems, such as a gas supply problem or issues with the entire central heating system.

It's crucial to read the fine print of any policy, as exclusions can include:

  • Pre-existing issues with the boiler prior to taking out the cover.

  • Boilers beyond a certain age or without regular servicing.

  • Repairs required due to misuse or unauthorised DIY fixes.

Residents should ensure they have a policy that matches their needs and understand the process for claiming should a boiler issue arise. This knowledge can save both time and money and ensure that proper procedures are followed to rectify any boiler-related problems promptly and safely.

iHeat 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.

Effectively, new boiler cost 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


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System to combi conversion


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New boiler install


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Back boiler to a combi


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System to system


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Frequently Asked Questions

What happens if my boiler is broken?

If a boiler is broken, it ceases to function properly, which can affect heating and hot water supply in the home. In some cases, it may also present a risk to safety, necessitating immediate attention.

Is a broken boiler an emergency?

A broken boiler can be considered an emergency, especially during colder months or if there are vulnerable individuals in the home. Gas leaks or any signs of carbon monoxide should be treated as urgent safety risks.

How do you know your boiler is broken?

Signs of a broken boiler include unusual noises, such as banging or whistling sounds, water leaks, a lack of hot water or heating, error codes on the display panel, and an unexpectedly high fuel bill.

How much does it cost to fix a boiler?

Repair costs for a boiler can vary widely depending on the issue and parts needed. Minor fixes might cost from £50 to £150, while more extensive repairs could easily exceed £500.

How much does it cost to fix a boiler UK?

In the UK, boiler repair costs can range considerably, with average prices from £100 to £500; however, more complicated repairs or replacements of significant components may be more costly.

Is it worth replacing a boiler?

Whether to replace a boiler depends on its age, efficiency, and the frequency of breakdowns. If a boiler is over ten years old, inefficient, or requires constant repairs, it may be more economical in the long term to replace it.

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.