How to balance your radiators

Free DIY guide — no sign-up required. Written by a qualified Gas Safe engineer.
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Most likely cause & what to check

1

Balancing ensures all radiators reach temperature at roughly the same time. Start with all lockshield valves (the plain-capped valve end) fully open.

2

Turn the heating on from cold and note the order in which radiators heat up — nearest to the boiler heats first.

3

Once all radiators are hot, use a thermometer to measure the flow and return temperatures at each radiator. Ideal difference is 12°C.

4

Start with the radiator that heats up last (usually furthest from boiler) — leave its lockshield valve fully open.

5

Work back towards the boiler, progressively closing each lockshield valve slightly to restrict flow and achieve the 12°C difference.

6

It may take 2–3 cycles of heating and adjusting to get it right. The result is even heat distribution and better efficiency.

🛠 Tools & materials you may need

Lockshield valve key or pliersRadiator thermometer or digital probe
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