Terms of use

The tools and materials provided from this page have been designed (on the whole) for engineers and are not neccessarily designed for end user operation.

They may require engineering judgment and personal verification of provided data. Although I have worked hard and made these tools as accurate and functional as possible, I provide no warranty on their accuracy or suitability.

All tools used from this page are done so at the user's own risk.

If you do not know the output of the radiator, you can try my radiator estimator....

Required flow across the radiator = l/min

Required values are technically outside the performance ability of the current range of Drayton auto-balancing valves.

Further information on these valves is available from the manufacturer's website. This calculator expands on the data provided within the product leaflet. It is only relevant for the latest "auto balancing" versions of the TRV4 and RT414.

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Updated 01 February 2026 in engineer tools.

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