M
mysteryman
The way to do this is to have a small radiator or heated towel rail without thermostatic valve as the bypass circuit. The lockshield valves on it are set to provide the minimum flowrate when all TRVs are closed. This will dissipate residual heat during pump overrun [on an S Plan it needs to branch off before the 2 port valves].
With weather compensated control, the flow temperature is varied to suit the load, and TRVs will not be closing completely. Accurate control of a bypass is then irrelevant.
With weather compensated control, the flow temperature is varied to suit the load, and TRVs will not be closing completely. Accurate control of a bypass is then irrelevant.