A heating system airlock can be frustrating, especially during colder months when you rely on your radiators for warmth. If your heating system is struggling to circulate hot water, leaving radiators cold, making unusual noises, or causing low water flow, you may have an airlock preventing proper operation.
Learning how to remove an airlock from your heating system can save you time, money, and unnecessary discomfort. This guide will provide a detailed step-by-step approach to help you get the air out of your central heating system and keep it running efficiently.
Key Takeaways
- Cold radiators, noisy pipes, and weak hot water flow often indicate an airlock in the heating system.
- The best way to remove an airlock is by bleeding radiators or using a hose to force the airlock out of the heating system.
- Regular maintenance, boiler pressure checks, and system flushing help prevent airlocks in the future.
- If multiple radiators stay cold despite bleeding, calling a professional heating engineer may be necessary.
What Is an Airlock in a Heating System?
An airlock in a heating system occurs when air gets trapped inside pipes or radiators, blocking the normal circulation of hot water. This prevents heat from reaching your radiators evenly, leading to cold spots, inefficient heating, and increased energy usage.
But does an airlock stop a heating system from working? The short answer is: Yes, it can. A severe airlock can completely stop hot water circulation, meaning some radiators will stay cold no matter how high you turn up the heating. This is why it’s essential to get rid of air in the heating system before the issue worsens.
Signs Your Heating System Has an Airlock
Wondering if you have an airlock in your central heating system? Here are the most common symptoms:
- Cold radiators, even when the heating is on.
- Uneven heat distribution – some radiators work, while others remain cold.
- Reduced hot water flow at taps and showers.
- Gurgling, bubbling, or banging noises from pipes and radiators.
- Low boiler pressure, which keeps dropping after refilling.
If you’re experiencing any of these issues, you likely need to bleed air from your heating system to restore normal circulation.
Common Problems Caused by Airlocks
1. Uneven Heating & Cold Radiators
An airlock in a central heating system causes hot water circulation issues, meaning some rooms might feel warm while others remain freezing cold. Since air rises, it often collects in higher radiators, blocking hot water from flowing properly.
Knowing how to fix the airlock in the heating system ensures consistent warmth throughout your home.
2. Increased Boiler Strain & Higher Energy Bills
When an airlock stops hot water flow, the boiler must work harder to circulate water. This leads to:
- Higher energy consumption and increased bills.
- Overheating in some areas while others remain cold.
- Potential long-term damage to your heating system.
By learning how to remove air from the heating system, you can avoid unnecessary strain on your boiler and reduce heating costs.
3. Noisy Pipes & Gurgling Radiators
If you hear gurgling, banging, or bubbling sounds, it means trapped air is disrupting water flow. This can lead to blockages, making it harder for your boiler to push hot water through the system.
If you’re unsure about how to unblock the airlock in the heating system, don’t ignore these noises—fixing the problem early prevents bigger issues later.
See Related: How to Stop Cold Air Coming Through Vents
Tools You’ll Need to Remove an Airlock
Before you start, gather these essential tools:
- Radiator Bleed Key: To Open radiator valves to release trapped air.
- Towels & a Container: To catch any escaping water.
- Adjustable Spanner: Useful for stubborn radiator valves.
- Pressure Gauge: Helps monitor boiler pressure levels.
For more advanced fixes, consider:
- Infrared Thermometer: Identifies cold spots in radiators.
- Hosepipe: Used for forcing out airlocks in pipes.
- Magnetic Filter: Prevents sludge buildup, improving efficiency.
How to Remove Airlock From Your Heating System
There are two main ways to get air out of a heating system:
- Bleeding radiators: The simplest and most common method.
- Using a hose to force out airlocks: A more advanced method for persistent airlocks.
Method 1: Bleeding Radiators to Release Trapped Air
Bleeding your radiators is the easiest way to clear an airlock in the heating system.
Step-by-Step Guide
- Turn off the heating and let the radiators cool.
- Locate the affected radiator – usually the highest one in the house.
- Insert the radiator bleed key into the bleed valve.
- Slowly turn the key counterclockwise until air hisses out.
- Once water flows steadily, close the valve.
- Check the boiler pressure – If it drops below 1 bar, refill using the filling loop.
This method should remove air from the heating system and restore normal hot water flow.
Method 2: Using a Hose to Force Out Airlocks
If bleeding doesn’t work, you may need to use a hosepipe to unblock the airlock in the heating system.
Step-by-Step Guide
- Turn off the heating and wait for the system to cool.
- Attach a hosepipe to the radiator drain valve.
- Open the radiator valve and let water flow until all air bubbles are gone.
- Close the valve and remove the hose.
- Turn the heating back on and check if the radiator heats up.
This method forces the airlock out of the heating system and helps restore proper water circulation.
When to Call a Professional
Sometimes, DIY fixes aren’t enough. Call a heating engineer if you notice:
- Multiple radiators stay cold, even after bleeding.
- Unusual boiler noises persist.
- Frequent pressure drops or leaks.
- Sludge buildup, requiring a power flush.
At ResTemp Solutions, we specialise in diagnosing and resolving airlocks, trapped air, and pressure issues in central heating systems. With over 30 years of experience in heating, ventilation, and air conditioning, we provide expert solutions tailored to domestic and commercial heating systems across Cork. Our team ensures optimal comfort and energy efficiency by identifying underlying system faults and implementing long-lasting fixes.
Preventing Airlocks in Your Heating System
Regular Maintenance Tips
- Bleed radiators twice a year to prevent trapped air.
- Keep boiler pressure between 1.5-2 bar.
- Flush the system periodically to remove sludge.
- Check for leaks and faulty valves.
Frequently Asked Questions
Will an Airlock Clear Itself?
No, an airlock won’t clear itself. You must bleed the system or use a hose to remove air from the heating system.
What’s the Best Way to Clear an Airlock?
Bleeding radiators is the quickest solution. If that fails, use a hosepipe method to force the airlock out of the heating system.
Conclusion
Knowing how to remove the airlock from your heating system ensures efficient heating and lower energy bills. Regular maintenance, pressure checks, and occasional radiator bleeding keep your heating system running smoothly.
