As a heating engineer, one of the most common issues I come across is uneven heating in radiators and fluctuating boiler pressure. Fortunately, these are simple maintenance tasks you can often carry out yourself. Here’s a step-by-step guide to help you keep your heating system running efficiently.
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Why Bleed Radiators?
Over time, air can become trapped inside your radiators. Instead of filling with hot water, parts of the radiator (usually the top) remain cold. This reduces efficiency and leaves rooms feeling cooler than they should. Bleeding your radiators removes the trapped air so hot water can circulate properly again.
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How to Bleed a Radiator
What you’ll need:
• A radiator bleed key (or a flat-head screwdriver for some models)
• A cloth or small container to catch drips
• Protective gloves (optional)
Steps:
1. Turn on your heating – Let your system warm up so you can identify which radiators are not heating fully. Feel the top and bottom of each radiator; if the top is cooler, it needs bleeding.
2. Switch off the heating – Always turn your boiler off before bleeding radiators. This prevents more air from being drawn in and avoids hot water spraying out.
3. Locate the bleed valve – This is usually a small square or slot on the top side of the radiator.
4. Insert the key and turn slowly – Turn anti-clockwise just enough for air to hiss out. You’ll hear a steady escape of air.
5. Catch the water – When water begins to flow steadily (without sputtering), the air is gone. Tighten the valve clockwise. Don’t overtighten, just make sure it’s snug.
6. Repeat if needed – Go through all radiators in your home, starting with the one furthest from the boiler and working your way back.
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Checking Your Boiler Pressure
After bleeding radiators, it’s important to check the boiler pressure because letting air out can cause the system pressure to drop.
Steps:
1. Find the pressure gauge – This is usually on the front of your boiler.
2. Check the reading – Most boilers should sit between 1.0 and 1.5 bar when the system is cold. If it’s below 1.0 bar, your system needs topping up.
3. Re-pressurise if needed –
• Locate the filling loop (a silver flexible hose with small taps at each end, usually underneath the boiler).
• Open both taps slowly until you hear water filling the system and the gauge rises to around 1.2–1.5 bar.
• Close both taps firmly once the correct pressure is reached.
4. Turn the heating back on – Check your radiators again to make sure they’re heating evenly.
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When to Call a Heating Engineer
• If you’re bleeding radiators frequently (more than once or twice a year), it could indicate a larger problem such as a leak, faulty expansion vessel, or pump issue.
• If your boiler pressure keeps dropping even after topping up, you may have a hidden leak or a faulty pressure relief valve.
• If you’re unsure at any stage, it’s always safer to call a professional.
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Final Thoughts
Regular radiator bleeding and pressure checks are simple but essential tasks to keep your heating system efficient and your home comfortable. Doing this maintenance can reduce energy bills, prevent breakdowns, and prolong the life of your boiler.
t: 07704141410
w: gascareplus.com
