Why is an Automatic Bypass Valve (ABV) required on evohome?

[Richard]

The evohome system when used with HR92 Radiator Controllers on all radiators is exactly the same as an 'S Plan Plus' system in its design.

The majority of boiler manufacturers these days have a built in ABV as part of the boilers hydraulic assembly, however it is extremely important that the correct minimum flow rate is maintained through the boilers heat exchanger at all times.

I always recommend asking the relevant boiler manufacturer if their boiler is fitted to an 'S Plan Plus' system would it require an ABV? If the answer is 'Yes' then an evohome system with HR92's fitted to all radiators would need one too!

Remember, ABV's ensure minimum flow rates are achieved, system pressure is reduced (as TRV's modulate down) and system noise is reduced.