Condensing boiler - which dial?

[StephenStephen]

Different engineers have been clear that only one of these two dials on our boiler does something, and the other one doesn't.

Can you remind me which it will be?
Many thanks, Stephen

I'm looking to reduce the temp to maximise efficiency, whilst still having the heating and hot water hot enough.

Worcester 35 CDi Classic System ErP About 6 or 7

years old

 

[Jurassicspark]

The left one is for your radiators and the one on the right is for your hot water.

 

[StephenStephen]

The left one is for your radiators and the one on the right is for your hot water.

Thanks for your reply - apparently in the setup here one does nothing and the other does something....

 

[Jurassicspark]

It might say so in the boilers manual. Have you checked it out yet?

 

[StephenStephen]

Thanks - I'll have a look in the manual - didn't think of that!
Here's a photo of the pipework underneath:

 

[Jurassicspark]

Is it a system boiler?

The second image shows how to adjust the heating temperature, ideally you want it to be set around 4 to allow the boiler to condense.

 

[StephenStephen]

View attachment 364521View attachment 364524

Is it a system boiler?

The second image shows how to adjust the heating temperature, ideally you want it to be set around 4 to allow the boiler to condense.

Yes it's a system boiler - thanks for the images - it's now resurfaced in my memory - we don't have the optional diverter valve so it's just the left hand heating dial that controls the boiler temp.
Very grateful for your help on this, cheers, Stephen