Viessmann vitodens 200 low modulation low run time high return temp

[JonathanM]

Oops forgot to put what it was!
The flue was set to balanced flue rather than single

Thanks for updating. Glad it's working properly now. It was behaving very strangely!

The two options for this model seem to be "Single connection" and "Multiple Connections". Single seems to be default, so it looks like your engineer chose to use multiple originally, which seems a bit odd.

■ Single connection Only one heat generator is connected to the flue system (factory setting). ■ Multiple connections Several heat generators are connected to the flue system.

 

[monkeysballs]

That was what I meant

 

[dormermike]

Last 3 hours of modulation attached.

I do think it's getting too hot as looking at my flow (supplied by the boiler rather from my sensors on the pipes also attached)

So what should I do to get it to run longer/modulate more?

Hi, @monkeyballs wanted to DM you but your profile is restricted. I'm wondering how you got these graphs showing modulation please? I've a viessmann 111 and want to see what it's doing in terms of return temps and modulation over time. Thanks