Regularly bleeding radiators enhances the efficiency and performance of your heating system, making your home more comfortable during those cold winter months. It’s also essential to follow proper safety measures to ensure the job is done effectively. In this guide, we’ll walk you through a step-by-step process for bleeding radiators and highlight common mistakes to avoid, as well as provide troubleshooting tips for any issues that may arise during the process. Equipped with these insights, you’ll keep your heating system running smoothly and efficiently.
What does ‘bleeding radiators’ mean and what’s involved?
Bleeding radiators is the process of removing trapped air from a radiator to improve heating efficiency. Over time, air can accumulate in your radiator, preventing hot water from circulating properly, leading to ‘cold spots’ and reduced heating performance. To bleed a radiator, you need to use a special metal or plastic, T-shaped or square key to turn and open the valve, releasing the trapped air. This causes a hissing sound until water starts flowing steadily.
The process is simple but important for maintaining your heating system. When the air escapes, the radiator is able to fill with water, allowing the central heating system to operate more efficiently.
How often should you bleed radiators?
You should bleed your radiators at least once a year, typically before winter arrives in order to ensure the efficiency of your heating system. Regularly checking for trapped air also helps to make sure that your system operates effectively and reduces energy consumption. In some cases, you may need to bleed your radiators more frequently if they aren’t heating up fully or if you notice cold spots. For example, if you notice uneven heating on the radiator’s surface, it’s a sign that air may have built up inside the radiator.
It’s important to note that radiators in a well-maintained system generally don’t require frequent bleeding. However, older systems or those with visible leaks may require bleeding more often. Additionally, if you’ve had work done on the heating system in preceding months or added new radiators, bleeding may be necessary as air can enter the system during those changes.
By staying on top of bleeding radiators, you ensure your home stays warm and your heating system remains efficient.
What order do you need to bleed radiators in?
When bleeding radiators, the correct order is essential for efficient air removal and optimal heating performance. We recommend starting with the radiator farthest from the boiler and work your way towards the closest. This is because the radiators that are furthest away from the boiler are more likely to have trapped air and, by starting with them, you help push air towards the nearest radiators. This ensures that air is properly expelled from the entire system, allowing the water to circulate evenly.
Additionally, bleeding one radiator at a time ensures no air is sucked back into the system, maintaining pressure and preventing potential damage. For systems with multiple floors, it’s best to start on the top floor and move down. This helps gravity assist in pushing the air out of the system, making the process more effective.
Properly following this order also prevents unnecessary strain on the pump and improves the overall efficiency of your heating system. Always ensure the system is not under pressure, and remember to use a towel to catch any water drips during the process.
Why do radiators need bleeding?
Bleeding your radiators is essential for maintaining the efficiency of your heating system. By removing the trapped air, you allow hot water to circulate freely, improving the radiator’s performance. Regularly bleeding your radiators also helps prevent the pump from overworking and potential damage to the system.
What happens if you don’t bleed your radiators?
If you neglect to bleed your radiators, the trapped air will cause several issues:
- Cold spots – air pockets prevent water from circulating properly, causing cold spots, particularly at the top of radiators, reducing the overall heating efficiency of the system.
- Reduced heating efficiency – when air is trapped, your radiator can’t heat evenly, leading to your system working harder, increasing energy consumption.
- Increased pressure – trapped air affects the system’s pressure, potentially causing the pump to overwork, which can result in wear and tear or even system failure.
- Higher energy bills – because the system is less efficient, you may need to run your heating for longer or at higher temperatures to achieve the same level of warmth, leading to higher energy costs.
- Potential damage to your boiler – ongoing pressure issues due to trapped air can strain the entire system, increasing the likelihood of costly repairs or boiler damage over time.
A simple step by step guide to bleeding a radiator
Follow our five step process to bleed your radiator:
- Turn off heating and gather tools: ensure the system is off and the radiators are cool to prevent hot water from causing burns or injuries. Prepare a radiator key, an old towel and a small bowl for catching water.
- Locate the bleed valve: At the top of the radiator, you’ll find the bleed valve, usually on the side or top. It is a small metal valve with a square or slot opening.
- Insert the key and open the valve slowly: Insert the radiator key and slowly turn it anticlockwise to release air. You should hear a hissing sound as air escapes. Let the air escape until water starts to flow steadily.
- Close the valve: Once the water flows without sputtering, quickly turn the key clockwise to close the valve tightly.
- Check system pressure: After bleeding, check your heating system’s pressure gauge. If the pressure is low, you may need to top up the system using the filling loop, i.e. a hose usually located near the boiler, which allows water to enter the boiler system, topping up pressure by connecting the boiler to the mains.
Tools and safety
Before starting, gather the essential tools needed for bleeding your radiator. You’ll need:
- the radiator key, which is available at most hardware or DIY shops, or you can purchase it online.
- rags, old towels or cloths ready to catch any water that may spill out during the process.
- a small bucket or container for catching excess water.
- gloves, particularly if the radiator or valves are still hot when bleeding starts.
Safety is paramount when bleeding radiators. Ensure that the radiator is not too hot before attempting to bleed it to avoid injury to yourself or damage to your property. It’s advisable to turn off the heating system and allow ample time to let the radiator cool down before proceeding.
| If you’re dealing with a high-pressure system, take extra caution to avoid accidental pressure release, which could be extremely dangerous. |
When working with the filling loop, make sure to monitor the pressure gauge closely and avoid overfilling. Always check for leaks after finishing the process and ensure that all valves are properly closed to prevent water damage or pressure loss.
Expert tips: common mistakes to avoid
When bleeding radiators, there are several common mistakes to avoid:
- Use the correct radiator key – avoid makeshift tools, such as using a screwdriver. Using the wrong key or excessive force can damage the valve, causing leaks.
- Seal the valve properly – ensure the valve is tightly closed after bleeding to prevent air from re-entering the system and causing further issues.
- Clean up water spills – catch water and prevent floor damage or rust from prolonged exposure.
- Bleeding too quickly – rushing through the process can cause air to get trapped in the system. Bleed slowly, allowing the air to fully escape.
- Ignoring unusual noises – if you hear gurgling or banging noises after bleeding, it may indicate trapped air or low pressure, which could mean the system needs further attention.
- Not replacing faulty valves – if a valve doesn’t close properly after bleeding, don’t ignore it. A faulty valve can continue to leak, causing ongoing issues with heating efficiency
| Learn more DIY plumbing tips here |
Troubleshooting advice
While bleeding radiators is a straightforward process, there are several common issues you may encounter:
- Stuck valves – if your radiator valve won’t turn, it may be stuck due to mineral buildup or wear. Try using a pair of pliers gently or applying some penetrating oil. If that doesn’t work, you might need to replace the valve.
- No heat after bleeding – if your radiator is still cold after bleeding, ensure you’ve bled all radiators, including the one farthest from the boiler. If the problem persists, it may be an issue with the circulation pump or airlock.
- Cold top or bottom of the radiator – a radiator with one part colder than the other often has sludge buildup or a blockage. This requires a powerflush or cleaning of the system by a professional to remove the sludge and restore even heat distribution.
Improving your heating efficiency
By regularly checking and removing trapped air on an annual basis, you ensure that your radiators heat your home more effectively, avoiding common issues like cold spots and increased energy consumption. Following the correct order, using the right tools and taking safety precautions will help you maintain an optimal heating system, keeping your home warm and cosy during the colder months.
FAQs
How long does it take to bleed air out of a radiator?
Bleeding a radiator typically takes 5-10 minutes per radiator. The process involves using a radiator key to release trapped air until water flows steadily out. If multiple radiators are involved, the time may vary. Larger systems or stubborn air pockets may take longer. It’s essential to be patient, allowing each radiator to fully release air.
Should radiators be cold or hot when you bleed them?
Radiators should ideally be cold when you bleed them. This ensures that no pressure from hot water interferes with the air release process, and you’re less likely to burn yourself during the procedure. Let the radiator cool completely before starting. If you must bleed a hot radiator, proceed carefully by using protective gloves and towels to handle any hot water that might escape. It’s safer and more effective when the system is off and cool.
Do you turn the boiler off when bleeding radiators?
Yes, the boiler should be turned off when bleeding radiators. Turning off the boiler ensures safety, as hot water or steam won’t escape when the bleed valve is opened. Additionally, it prevents pressure from being added to the system, which could cause unnecessary spillage or leaks. After bleeding, you can turn the boiler back on and check the pressure level to ensure it’s correct.
Paine Manwaring is an established, professional and highly experienced supplier of plumbing, heating and electrical services to domestic and commercial customers throughout Sussex, Surrey and Hampshire.
For more information about the heating, plumbing and electrical services which we provide for both homes and businesses get in touch with a member of our expert and friendly team today on 01903 237522 or enquiries@painemanwaring.co.uk (Worthing) or 01243 784711 or info@painemanwaring.co.uk (Chichester).