Older Baxi Solo condensing boiler - optimum temperature setting?

[Koko88]

I have an older Baxi Solo 18 HE condensing boiler which is working fine. It’s very basic with a boiler temperature control.

The boiler temperature control knob is very basic setting displaying low to high, turn clockwise to increase, anti clockwise to decrease temperature.

What is the optimum to set the temperature control knob for best temperature and efficiency?

The instructions doesn’t actually have any information on optimum setting.

I have uploaded a diagram of the boiler temperature control knob

 

[ShaunCorbs]

Need a temp guage on the flow you want it around the 65 dc mark

 

[Koko88]

H

Need a temp guage on the flow you want it around the 65 dc mark

 

[Koko88]

Need a temp guage on the flow you want it around the 65 dc mark

 

[Koko88]

A temperature gauge on the flow, is that on the flow pipe, I presume?

If not, please explain

Thanks

 

[ShaunCorbs]

Yes spot on eg the hottest pipe out the top of the boiler