Introduction
If you live in Bentworth and have noticed cold spots on your radiators or hear gurgling noises when the central heating kicks in, you might have an airlock in your system. Airlocks occur when trapped air prevents hot water from circulating properly, leading to uneven heating and higher energy bills. While this is a common issue in areas such as Bordon (GU35), Alton, Farnham and Petersfield, the good news is that you can often clear these airlocks yourself with a few simple steps.
What Is an Airlock?
Causes of Airlocks
An airlock forms when pockets of air become trapped in the pipework or radiators. This can happen after:
- A recent heating breakdown or power cut.
- System maintenance or boiler servicing.
- Installing a new boiler installation or moving radiators.
- Leaks that allow air to enter the system.
Signs You Have an Airlock
- Cold patches on radiators, often at the bottom.
- Gurgling or bubbling sounds when the heating is on.
- Low system pressure despite topping up.
How to Remove an Airlock From Your Heating System
Follow these steps to safely remove an airlock from your radiators. Always proceed with caution and, if in doubt, call a qualified Gas Safe engineer.
1. Turn Off the Boiler
Before starting any work, switch off the boiler and allow it to cool down for at least 30 minutes. This helps prevent hot water burns and keeps you safe.
2. Locate the Affected Radiator
Identify which radiator or section of pipework is cold at the bottom—that’s where the airlock is likely trapped.
3. Bleed the Radiator
Bleeding is the most common way to release trapped air:
- Gather your tools: a radiator bleed key, a cloth, and a small bucket.
- Place the cloth under the bleed valve at the top of the radiator.
- Insert the bleed key and turn anticlockwise slowly. You should hear a hissing sound as air escapes.
- Once water starts to trickle out, tighten the valve by turning it clockwise.
- Wipe away any drips and check the pressure gauge on the boiler.
4. Re-pressurise the System
After bleeding, your boiler pressure may drop below the recommended level (usually around 1.0–1.5 bar). Use the filling loop to top up:
- Locate the filling loop beneath your boiler.
- Open the valves on the loop until the pressure gauge reads the correct level.
- Close both valves tightly to prevent leaks.
5. Restart and Test
Turn the boiler back on and allow the system to heat up. Check each radiator for warmth and listen for any remaining gurgling sounds. If the issue persists, repeat the bleeding process or move on to other radiators in the same zone.
When to Call a Gas Safe Engineer
If bleeding your radiators and re-pressurising doesn’t clear the airlock, or if you suspect a deeper fault like a faulty pump or corrosion, contact a qualified professional. Persistent issues can lead to expensive boiler repair or even premature replacement. A Gas Safe engineer can diagnose radiator problems, carry out complex repairs and recommend upgrades such as magnetic filters or improved pipe insulation.
For homeowners across GU34 and nearby GU35 areas, regular maintenance can prevent unexpected heating breakdowns. Consider bespoke boiler cover to protect against costly call-outs.
Preventing Future Airlocks
After clearing an airlock, keep your system running smoothly with these tips:
- Schedule annual boiler servicing to catch small issues before they grow.
- Balance your radiators by adjusting the lockshield valves to ensure even heat distribution.
- Install a magnetic filter to remove sludgy debris that can trap air and cause blockages.
- Check your system pressure monthly and top up if needed.
- Avoid frequent power flushing unless recommended by a Gas Safe engineer, as this can introduce more air.
Understanding the Costs
Bleeding a radiator and re-pressurising the system is a DIY-friendly task that usually costs nothing but a few minutes of your time. However, if you face recurring airlocks, you may need to invest in professional services. Factors that affect costs include:
- Hourly rates for a Gas Safe engineer
- Replacement parts for valves or pumps
- Additional service like power flushing
- Long-term protection with a boiler cover plan
Conclusion
Airlocks are a common cause of inefficient heating in Bentworth, Liphook, Bordon and surrounding areas. By following these safe, step-by-step instructions, you can restore warmth to your radiators and avoid a full-scale heating breakdown. Remember, if in doubt, always call a qualified Gas Safe engineer to ensure your system remains safe and reliable.
Frequently Asked Questions
How often should I bleed my radiators?
It’s best to bleed radiators at the start of the heating season and whenever you notice cold spots. Regular checks can prevent airlocks from building up.
Can I bleed my radiators while the boiler is hot?
No, always turn off the boiler and allow the system to cool for at least 30 minutes to avoid hot water burns.
My pressure keeps dropping after bleeding—what now?
If pressure falls below 1 bar frequently, you may have a leak or faulty component. Consult a Gas Safe engineer for a thorough inspection.
If you need help with your heating or boiler, our local engineers are here to help. Call us on (01420) 558993 or book online at embassygas.com/book.
Written by Embassy Gas — your local heating experts covering Bordon, Alton, Liphook, Farnham and surrounding areas.