As the colder months settle in across Newbury and the surrounding areas of Berkshire, Hampshire, and Oxfordshire, there is nothing more frustrating than turning up the thermostat only to find your living room remains chilly. A common issue we encounter at Sanju's Heating & Plumbing is a radiator that feels warm at the bottom but stone cold at the top.
This specific symptom is usually a clear indicator that trapped air has entered your central heating system. When air gets stuck in the top of a radiator, it prevents the hot water from circulating properly, effectively creating an air pocket that stops the metal from heating up.
Why Does Air Get Trapped in Radiators?
Air can enter your heating system through several different channels. Sometimes, it happens naturally over time, or it can be introduced during maintenance work where the system was partially drained.
- Micro-leaks: Tiny pinhole leaks in joints or valves can draw air into the system when it cools down.
- Corrosion: Internal pipework corrosion can create hydrogen gas as a chemical byproduct, which collects at the highest point of your radiators.
- Fresh Water: When you refill or top up a system, the fresh water contains dissolved air that is released as the water heats up.
While this is a common and usually manageable issue, if you find yourself bleeding the same radiator repeatedly, it could indicate a deeper problem with your system that requires professional attention from a Gas Safe registered engineer.
How to Bleed Your Radiators Safely
Bleeding a radiator is a relatively straightforward task that most homeowners can perform themselves. Before you begin, ensure your heating system is turned off and the radiators have completely cooled down to avoid the risk of scalding.
- Locate the bleed valve, which is usually found at the top corner of the radiator. It looks like a small square nut within a round metal casing.
- Use a radiator key or a flat-head screwdriver to slowly turn the valve anti-clockwise. You should hear a hissing sound as the trapped air escapes.
- Keep a cloth or a small container handy to catch any water that may escape once the air has finished venting.
- As soon as you see a steady stream of water rather than air, tighten the valve clockwise until it is firm. Do not overtighten, as this can damage the valve.
- Once finished, check your boiler pressure. Bleeding radiators often causes a slight drop in pressure, so you may need to top it up to the recommended range.
Safety Warning: Never attempt to repair or adjust internal boiler components yourself. If your radiator remains cold after bleeding, or if you suspect the issue is related to your boiler's internal gas components, always use a Gas Safe registered engineer. Our local team in Newbury is happy to help if you are unsure.
What If Bleeding Doesn't Fix the Problem?
If you have bled your radiators and they still refuse to heat up, the issue might not be air at all. It could be a build-up of sludge and magnetite, which settles at the bottom of the system but can restrict overall flow and thermal efficiency.
If the entire radiator feels cold, or if there are patches of cold spots in the middle, you may be dealing with a blockage. In these instances, a power flush may be required. This is a professional service where we use specialised equipment to force a high-velocity flow of cleaning chemicals through your system to dislodge stubborn debris.
The Importance of Annual Boiler Servicing
Prevention is always better than cure. Having your boiler serviced annually by a Gas Safe registered engineer is the best way to ensure your entire central heating system operates at peak efficiency.
During a service, we don't just check the boiler's safety; we also inspect the pump, check system pressure, and ensure that your radiators are distributing heat evenly. For residents across Berkshire, Hampshire, and Oxfordshire, regular maintenance is the secret to avoiding expensive emergency call-outs during the heart of winter.
When to Call the Professionals
If you are ever in doubt, don't hesitate to reach out to us at Sanju's Heating & Plumbing. It is far better to have a professional take a look early than to leave a fault to worsen, which can lead to higher energy bills or a complete system breakdown.
- If your boiler pressure drops repeatedly after bleeding.
- If you notice visible leaks around your radiator valves.
- If your boiler is making banging or rattling noises.
- If you are uncomfortable performing the bleeding process yourself.
We pride ourselves on being a reliable, family-run business that puts your safety and home comfort first. Whether you are in a modern home in Newbury or a period property in the Oxfordshire countryside, we are here to help keep your pipes flowing and your radiators hot.
