Considering Viessmann 111-w

[dormermike]

Hello

Would anyone be kind enough to help me decipher the specs below on that picture for an incoming flow rate of 16-18lpm please?

It's for a vitodens 111 wall mounted storage combi, to replace a stored vented system.

l Had wanted a unvented cylinder but don't really have space nor the flow.

Looking at the specification, I think between the 32kw and the 25kw I may as well get the 32 as the modulation drops it down to 3.2kw, but the overall flow is slightly higher, and both are higher than i'd need anyway but presumably the 32 will replenish the stored HW faster?

Also does 35C temp rise at 17l/min (for 25) mean it would struggle to heat the DHW at the taps in the dead of winter in the UK if we had another beast from the east?

Any help with these numbers and what they mean would be appreciated. I don't have a huge DHW demand but would be nice to have a shower and hot taps on at same time and this boiler seems to fit the bill.

Thanks

 

[dormermike]

From reading around, storage combi's seem not to be favoured, or perhaps i'm asking a silly question, but in any case, any opinions welcome.

 

[muggles]

You say you've not got the flow rate for an unvented cylinder. Do you know what your incoming flow rate actually is?

The 111-W is like having a washing machine hung on your wall. It's enormous. Personally I'd go for a Navien NCB700 42 or 54kW if you can get the gas supply over to it. You get up to 22l/min continuous flow rate at 35ºC temperature rise, modulation down to 3.4kW, stainless heat exchanger, 12 year warranty, and it's half the physical size.

 

[dormermike]

Yes my flow is 16-18lpm, sorry, thought I'd included that on the OP but hadn't.

Thanks for the suggestion I'll take a look. I'm not too worry about the size of the 111w tbh, as it's still less space than a unvented cylinder plus boiler so it actually frees up space (man maths). The existing setup is boiler, and tanks. I need the tanks gone, as need that space back.

A viessmann installer told me the 111w is fabulous bit of kit and I'll never run out of hot water ever, even running showers and hot taps at same time. Is that true of storage combi boilers?

 

[muggles]

All combi boilers provide a continuous supply of hot water. You can't get out more than you put in though, so if your incoming mains is only around 17l/min you're only ever going to get 17l/min out. I think the Navien would be perfect for you https://navien.co.uk/product/ncb-700-gas-condensing-combi-boiler/