The most common way to increase the flow to your radiator is by adjusting the lockshield valve.
To effectively increase the flow and improve your radiator's heat output, you'll likely need to balance your central heating system. Here's a breakdown of how to do that:
Understanding Lockshield Valves
Lockshield valves are located on one end of your radiator (usually the end without the thermostatic radiator valve (TRV)). They control the amount of hot water flowing into the radiator. Balancing your system involves adjusting these valves on each radiator to ensure they all heat up efficiently.
Balancing Your Central Heating System
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Identify the Radiators: Note the distance of each radiator from the boiler. The radiators closest to the boiler will naturally receive hot water faster.
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Fully Open All TRVs: Make sure all thermostatic radiator valves (TRVs) are fully open during the balancing process.
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Adjust the Lockshield Valves:
- Radiators Closest to the Boiler: Close the lockshield valve completely (turn clockwise). Then, open it gradually (turn counter-clockwise). Start with a small opening – perhaps a quarter or half turn.
- Radiators Furthest from the Boiler: Open the lockshield valve more than those closer to the boiler. These need a greater flow to compensate for the distance. Fully open the lockshield valve if necessary.
- Intermediate Radiators: Adjust lockshield valves proportionally based on their distance from the boiler.
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Bleed the Radiators: Once you've adjusted the lockshield valves, bleed each radiator to remove any trapped air. Use a radiator key to slowly release air from the bleed valve until water starts to drip out.
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Turn on the Heating System: Turn on your central heating system and monitor how the radiators heat up.
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Fine-Tune the Adjustments: After about an hour, check each radiator.
- Radiators Heating Up Too Quickly: Close the lockshield valve slightly more.
- Radiators Heating Up Too Slowly: Open the lockshield valve slightly more.
- Radiators Not Heating Up at All: Check that the TRV is open and the lockshield valve is open. Ensure the radiator is bled. If it still doesn’t heat, further investigation may be needed (e.g., blocked pipes).
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Repeat and Monitor: This is an iterative process. You may need to repeat steps 6 and 7 several times over a day or two to achieve optimal balance.
What if Balancing Doesn't Work?
If balancing doesn't solve the problem, consider these possibilities:
- Sludge Buildup: A buildup of sludge in the radiator or pipes can restrict water flow. A power flush may be necessary. This is a job best left to professionals.
- Blocked Pipes: A blockage in the pipes can also restrict flow.
- Incorrectly Sized Radiators: If a radiator is too small for the room, it will never heat it effectively, regardless of flow.
- Faulty Valves: Rarely, valves themselves can fail and restrict flow even when fully open.
Important Note
If you are uncomfortable working with plumbing, it is always best to consult with a qualified heating engineer.
