I have a pretty standard heating system, indirect cylinder, motorised valve to switch between rads, HW or both, etc.
A few rads upstairs have TRVs, downstairs the main rads have normal valves which are always open.

My question is where should I set my manual bypass valve? Should it be set differenlty in summer when no CH is on?

When it's fully closed, the rads perform the best. But I noticed this morning, it was quite mild, so the rads had not come on. The HW was on only, and I could hear a little gurgling in the HW tank. The valve was closed, but opening it a half turn or so stopped this.

During the winter, the HW window is only on when the CH is on as well.

Any advice appreciated.

If you have a 3-way motorised valve then 1 port is always open to the boiler and no bypass is needed and if one is fitted/opened then you are wasting gas.

Mog

Thanks.