Viessman Vitodens 111 35kw

[Steph83]

Hi guys, I've recently had a loft conversion and decided to get a new bolier installed at the same time.

My plumber decided to remove our tanked system in airing cupboard (this is where the stairs are now located) and to install a viessman Vitodens 111 35w combi up in the loft conversion.

Prior to installiation we queried the combi (several occasions) as we wanted to make sure the bolier was suitable for our now 4 bathrooms 3 bed house (2 ensuites, main bathroom and downstairs loo) but I was guaranteed it would to sufficient.

Boiler has since been installed and we do not have the pressure in our ensuite in loft conversion if the water is running downstairs. For example my daughter was running the bath downstairs and the water would trickle out in our ensuite in loft.

Our plumber came back and advised our water softer maybe causing issues so we got a new one installed which is the best on the market to improve pressure, annoyingly this didn't help! (water is however very soft). He then fitted restrictors to taps and baths excuding loft ensuite and this also hasn't helped. We also have good mains pressure as our property is only 12 years old.

My question is can anything be done / fitted to help the pressure? Secondly would any of you choose this bolier ahead of a unvented tanked system?

Amy advice would be appreciated

 

[ShaunCorbs]

What’s your mains flow rate and pressure standing and with one outlet running ?

 

[WC1]

Bump this as I've a customer set his heart on a 111 for a 4 bed house with 3 small bathrooms. I understand that pressure and flow can limit the performance of the 111 and this is likely to be op's problem as Shaun suggests.
(In his helpful question which the op has not yet answered)
My customer does have epic pressure and flow.
If go ahead, as I'm not entirely convinced ill make sure its recorded that I'm fitting it per customers instruction.
But more to the point, will it work with eg 2 showers running ??

 

[ShaunCorbs]

Will leave this here

 

[WC1]

I've seen that, is it real?

 

[ShaunCorbs]

I've seen that, is it real?

yep I can confirm as I’ve had two running and it didn’t slow water mains is key

 

[Gasmk1]

Fitted 4 of these on one we had all 3 showers running and a kitchen tap no problem

 

[gmartine]

...and what do you realistically need in terms of flow rate and pressure for simultaneous two shower use?

This model is really a game changer then?

 

[ShaunCorbs]

I would say around 4.5 bar and 30lpm

 

[Scott_D]

What manufacturers warranty do these come with for a non Viessmann installer?

 

[Gasmk1]

5 years I think, but pretty sure you can extend anyway as you pay to extend. Domestic gas boiler warranty registration - https://www.viessmann.co.uk/support/boiler-warranty-registration