Different flow temperature for CH and HW

[SgtFoley]

Hi

My setup: S plan, Unvented cylinder, Vaillant EcoTec 418 (all works fine).

The boiler has 2 knobs to set the flow temperature (for heating and water), but one of them seems to do nothing. i.e. the flow temperature target is what I set for the central heating independently of what the system is calling for.

Is this a standard limitation of an S plan system? Or is there a smarter way to do the wiring so the flow can be set separately?
I'm not sure what would happen if both CH and HW are called at the same time, but I can live with either outcome.

The reason for asking is that I would like a relatively low CH flow (55C) in Autumn... but this is too low for the water (legionella?). So I guess I'm currently forced to run my rads at 65C.

thank you!

 

[Dan Robinson]

s this a standard limitation of an S plan system

Yes

Or is there a smarter way to do the wiring so the flow can be set separately

Yes. Depending

I'm not sure what would happen if both CH and HW are called at the same time

Heating will run at a much higher temperature. There are ways of prioritising though.