Viessmann vitodens 200 low modulation low run time high return temp

[monkeysballs]

This is what the book says

 

[Johntheo5]

So, at 5% now, meter reading will reveal all.

 

[monkeysballs]

Ok so 3-4 1.56kw burnt 11minute burn time or 8.5kwh

 

[Johntheo5]

So, 1.56kwh burned in 11 minutes = boiler putput of 8.5kw, or 26.6% output (modulation), is this correct?

 

[monkeysballs]

Looks right for what it's saying it's modulation was

 

[Johntheo5]

But you have range rated it to 5% which means its output should only be ~ 1.7kw? So why is it outputting 8.5kw?. Did you take the meter readings?

 

[monkeysballs]

The readings are from my smart meter I could go sit out side and wit for it to burn but will do that when it's not raining and windy

 

[monkeysballs]

So major update it now works! Error by the engineer when installing the system.

so ive gone from 8 minutes burns to so far a max of 80 minutes! flow temps are also varying more and not overheating and single figure modulation! (but the rate has been varying unlike before) also the pump now turns off at times!

 

[monkeysballs]

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

 

[Johntheo5]

Why is it still cycling a little, assuming demand is still there, demand must be less than than ~ 2kw and if so the flowtemp would have to exceed the setpoint by 5C to trip the burner.

 

[monkeysballs]

I'd imagine it's because it can't really go any lower

 

[Johntheo5]

Are you happy now that the boiler can modulate now to < 2kw?.

 

[monkeysballs]

Yep more so the longer burn time as it evens the heat out just wish it was right for the last 2 months

 

[JackK]

Are you happy with the boiler? Is it complicated to use and very fiddly or are you pleased? Wanted to go for a 200 but thought it was way too complex and so settled for a 100 - Am I mistaken and should i reconsider a 200?

 

[monkeysballs]

It's very simple really once you get the curve and level set it's just fit and forget really