Draining water from a radiator involves a few steps to ensure a clean and safe process. Here's a step-by-step guide:
Steps to Drain a Radiator
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Turn Off Your Heating System: Before you start, completely turn off your central heating system and allow the radiator to cool down. This prevents scalding and pressure issues.
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Close the Thermostatic Radiator Valve (TRV): The TRV is usually the valve with numbers on it. Turn it to the lowest setting or close it completely. This valve controls the hot water flow into the radiator.
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Close the Lockshield Valve: This valve is usually covered by a plastic cap and is located on the opposite side of the radiator from the TRV. Count how many turns it takes to close the valve completely, and write it down. You'll need this number to reopen it to the original position later, ensuring balanced heating. Close it fully.
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Protect Your Flooring: Place towels and a container (a washing-up bowl is often sufficient) under the radiator valve you're about to loosen to catch any spills.
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Remove the TRV Nut (Slightly): Using an adjustable wrench, carefully loosen the nut connecting the TRV to the radiator. Loosen it just enough to break the seal, but don't remove it completely yet.
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Open the Bleed Valve: Locate the bleed valve (usually a small square or slotted screw at the top of the radiator) and use a radiator bleed key to slowly open it. This will release pressure from the radiator and allow air to enter, facilitating drainage. Have a cloth ready to catch any water that initially comes out.
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Remove the Lockshield Valve Nut (Slightly): Similar to the TRV nut, carefully loosen the nut on the lockshield valve. The water will begin to drain from this point. Control the flow by adjusting how much you loosen the nut.
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Collect the Water: Ensure the container is positioned to catch the draining water.
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Complete Drainage (Optional): If you need to completely remove the radiator, fully disconnect both nuts. Be prepared for a surge of water as you do so.
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Reassemble and Refill: Once you've completed your work on the radiator, reconnect it, tightening the nuts securely. Open the lockshield valve the same number of turns you noted earlier. Close the bleed valve.
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Refill and Bleed the System: Refill your central heating system and bleed all the radiators to remove any trapped air.
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Check for Leaks: Carefully check all connections for leaks.
Important Considerations
- Water Disposal: Radiator water can be dirty. Dispose of it responsibly, ideally down a drain.
- System Inhibitor: When refilling your system, consider adding a corrosion inhibitor to protect against rust and sludge buildup.
- Consult a Professional: If you are unsure about any part of this process, consult a qualified plumbing and heating engineer.
