Why Does My Boiler and Heating System Keep Getting Airlocks and Cut Out?

Why Does My Boiler and Heating System Keep Getting Airlocks and Cut Out?

A Regular or Conventional boiler relies on a gravity fed system from a cold water storage tank in a loft. This system is prone to airlocks, which can cause the boiler to lock out or cut out. If you are experiencing frequent issues with airlocks and circulation problems causing your boiler to cut out or air in radiators, the long term solution is to convert your gravity fed heating system to a pressurised heating system.

Options:

1. Install an expansion vessel and sealed system kit – This is a ‘semi conversion’ of your heating system only and will significantly reduce issues with airlocks but will not come with all the other benefits of a full system conversion. It can be an ideal choice for homeowners looking to reduce airlock problems without undergoing a complete overhaul of their system.
2. Replace the regular/conventional boiler with a system boiler – This is a full conversion of your heating and hot water system to a mains pressurised system resulting in 2-3 x higher cold and hot water pressure throughout the property. With this solution, not only will you resolve airlock issues, but you’ll also benefit from increased pressure, better water flow, and enhanced system reliability. This option is especially beneficial for larger homes where consistent hot water and efficient heating are necessary.

This article assumes that your property is too large or unsuitable for a combi boiler and that you already have or are installing a new Unvented hot water cylinder. If your property is suitable for a combi boiler, see our other blog about converting to a pressurised system with a combi boiler:

Benefits of Converting from a Regular Boiler to a Pressurised Heating System and a System Boiler

1. Improved Water Pressure & Flow Rate

• A system boiler works with an unvented cylinder, delivering mains pressure water directly to taps and showers. It eliminates the inconsistencies often experienced with gravity fed systems, where water pressure can fluctuate. Improved flow rates mean better performance in multi bathroom homes, and water supply at a stronger pressure. It enhances the overall experience for households with multiple occupants or bathrooms.
• Besides, the higher water pressure helps in making showers more enjoyable and reduces the time it takes for hot water to reach taps and showers. And it ultimately ensures that hot water is available across multiple outlets simultaneously without any noticeable drop in performance.

2. No Need for Cold Water Storage Tanks in the Loft

• One of the significant benefits of converting to a pressurised system is the elimination of the cold water storage tank and feed and expansion cistern in the loft. Not only does this free up valuable loft space for storage or other uses, but it also helps to reduce the risk of water contamination and the potential for freezing during winter months.
• Without the cold water tank, you omit the need for regular maintenance and inspections required to ensure its proper functioning. It also reduces the chance of leaks or water damage in your loft and offers peace of mind for homeowners.

3. Increased Energy Efficiency

1. System boilers are more efficient than regular boilers due to improved circulation.
2. Hot water in heating pipework is mains pressurised, so the central heating system heats up faster as hot water is rapidly pushed through the system pipework under pressure.
3. Unvented cylinders (installed together with a system boiler) are triple insulated and highly energy efficient, as they do not suffer from the significant heat loss of a copper cylinder. Hot water within stays hot all day until used. Learn more about unvented cylinders on our blog:

4. Minimal Chance of Airlocks & Pump Failures

• One of the main issues with gravity fed systems is the risk of airlocks, which can result in hot water and heating system failures. Pressurised systems eliminate the need for gravity fed water supply and greatly reduce the risk of airlocks and negate the need for central heating pumps or shower pumps. With the water being pressurised, it moves through the system more efficiently and consistently, meaning the chances of pump failures or issues related to air in the pipes are minimised.

5. Space Saving & Cleaner System

• Without a cold water storage tank and feed and expansion cistern, the system becomes much cleaner and more straightforward. Since all water in your system is fed directly from your cold mains water supply pipe, there is no risk of contamination from stagnant water, rust, or bacteria that can accumulate in a cold water storage tank. This also minimises the risk of Legionnaires’ disease, which can develop in poorly maintained water tanks.
• The removal of bulky tanks in your loft gives you the opportunity to reclaim this space for storage or even to transform it into a livable area, such as a loft conversion.

6. Fewer External System Controls to Fail

• A system boiler contains an internal pump and key components, which are covered by a 10 or 12 year manufacturer parts and labour warranty. This extended warranty offers you peace of mind that the critical components of your heating system are protected.
• In contrast, a conventional boiler has external components, such as the central heating pump or shower pump which are not covered under the boiler’s warranty. This can lead to additional maintenance costs and inconvenience as these components are more likely to fail over time.

7. Future Proofing for Upgrades

• A system boiler, together with an unvented cylinder, is ideal for larger properties and can easily provide heating and hot water for more than three bathrooms, multiple large radiators, and/or underfloor heating.
• If you are planning to add bathrooms, a loft conversion, or an extension, then a System boiler and Unvented hot water cylinder will be able to accommodate your future heating demands.

Wrapping Up!

Converting from a regular boiler to a pressurised heating system offers significant benefits, including improved water pressure, increased energy efficiency, and reduced risk of airlocks and pump failures. This upgrade not only enhances system reliability and performance but also provides long term savings and future proofing, making it a smart investment for larger properties or homes with evolving needs. However, if you need more details, please contact us directly. We’d love to help you!