Removing a radiator air valve (also known as a bleed valve) involves a few steps to ensure you do it safely and effectively. Here's a breakdown of the process:
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Turn off the heating system: Before you begin, switch off your central heating system to allow the radiator to cool down. This prevents hot water from spraying out when you remove the valve.
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Isolate the radiator (Optional but Recommended): For added safety, isolate the radiator by closing both the thermostatic radiator valve (TRV) and the lockshield valve. This minimizes water loss and pressure when you remove the valve. To do this, turn the TRV clockwise until it is fully closed. For the lockshield valve, count the number of turns it takes to fully close it, and write this down (you'll need this later). Close the lockshield valve.
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Gather your tools: You'll need a radiator bleed key or a small flathead screwdriver (depending on the valve type), an adjustable spanner or suitably sized wrench, and a cloth or container to catch any water that may escape.
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Locate the old bleed valve: This is typically a small valve located at the top of one end of the radiator. It usually has a square or slotted head.
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Bleed the radiator slightly (optional, but helps): If you haven't isolated the radiator, use your bleed key or screwdriver to carefully open the bleed valve slightly. Allow any trapped air and a small amount of water to escape into your cloth or container. This relieves pressure in the system. Be careful as the water may be hot if the radiator hasn't fully cooled.
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Loosen the old valve with the spanner: Grip the body of the bleed valve (not the bleed screw itself) with your adjustable spanner or wrench. Gently loosen the valve by turning it counterclockwise.
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Unscrew the old valve: Once loosened, you should be able to unscrew the valve the rest of the way by hand. Have your cloth ready to catch any remaining water.
Important Considerations:
- Water Loss: Even with the radiator isolated, some water may still escape. Be prepared to catch it with a cloth or container.
- Valve Type: Some bleed valves require a radiator bleed key, while others can be removed with a small flathead screwdriver.
- Replacement: If you're replacing the valve, ensure you have the correct size and type of replacement valve ready. Apply PTFE tape to the threads of the new valve before installation to create a watertight seal. After screwing in the new valve, reopen the radiator valves (if you closed them). Make sure to reopen the lockshield valve the exact number of turns you noted down.
- Tightening: When installing a new valve, don't overtighten it. Hand-tighten it, then give it a small turn with the spanner to secure it. Overtightening can damage the valve or the radiator.
- Re-pressurizing System: After replacing a valve, if significant water loss occurred you may need to re-pressurize your central heating system. Consult your boiler manual or a qualified heating engineer for instructions on how to do this safely.
