Viessmann 200 Modulation range

[andyman22]

Hi,

I've been speaking with my plumber and also with Viessmann and appear to be getting different answers, so wondered if anyone had any thoughts.

Looking at the Viessmann 200 system range, the modulation range for the 26kw and the 35kw appear quite different, with them both going down to the same lowest level (spec attached):
5.2 - 26 kW
5.2 - 35 kW

The plumber says this is a mistake, and Viessmann say the tech details are correct. I've looked at the various sites for different regions and it follows in all.

There's a negligible difference in cost, so if I were to go for a 26kw, is there any reason not to spec the slightly higher for the 35kW and presumably get a slightly faster DHW heat up time?
Thanks.

 

[muggles]

You're determined to have a Viessmann aren't you? At least you're going for the 200-series... If Viessmann say their details are correct, they're probably correct. No reason not to spec for the higher one at all if that's true, although it does seem odd that they make both models if they both do essentially the same thing. Your PDF is sideways and trying to read it is giving me a headache, so I'm just taking your word for it! You won't get a faster DHW heat-up time from the bigger boiler though, unless you go for a twin-coil cylinder, as the coil will only be rated to about 26kW

 

[andyman22]

Haha, thanks. Not so much, just that's what the plumber had originally talked about it. Will rotate the pdf now and re-upload.
Excellent point on the coil rating, so I'm guessing unless I need to heat the house with all the windows open, it'll probably never be utilised!

 

[muggles]

Don't worry, found it on the Viessmann website, and you do appear to be correct as far as I can tell; it does seem that both models are the same at the lower end of their modulation, in which case save yourself some pennies and get the smaller one

 

[andyman22]

Cheers, appreciate the help.