Is bypass valve needed with Tado X?

Peasmold

I currently have all 24 of my radiators set up with Tado X
I'm just about to replace the boiler Auto Bypass Valve (ABV) as it seems to be stuck open.

It got me thinking - with Tado controlling the boiler, circulating pump and TRVs, is there a need for a bypass valve?
Is the Tado system configured so that the boiler and pump are commanded off, before the last TRV is actually closed - thereby ensuring that the pump is never pumping against a closed system?

Montage

If a boiler requires an ABV, you should provide one. It allows it to run on and shed residual heat. It’s often the case that the boiler controls the pump.

wateroakley

@Peasmold If your boiler requires an external bypass, the heating design should provide a bypass. That may be a radiator without a TRV or an automatic bypass valve on the pipework. Modern boilers will usually control the pump over-run function. The over-run will dissipate excess heat from the boiler through the bypass. Without a bypass … when all the TRVs turn OFF, the boiler may go into an error mode and/or shut down.

Peasmold

Thanks both - that makes sense as it's the boiler that controls the pump on my system.