Viessmann/Worcester/vaillant

[shaya88]

I have done a extensive research and watched hours of videos about all of them and looking for the most suitable boiler for our house.

The house is 5 bed, 4 bathrooms, 20 radiators and maybe in future underfloor heating, 5 people living here and very rarely we use more than one bathroom. Flow is a big thing for me as all showers have a huge rain shower which I have not been able to use as our current combi is small one with flow rate of no more than 12 L/M, so I am looking at a minimum of 18L/M

I know most of you would say I should go for system boiler however due to lack of space I am keen to stick with combi, however I thought maybe storage combi would be a good compromise even though it doesn't work like a system boiler.

Worcester Greenstar 8000 Style 50kW is on the other is very powerful and I was not sure if its power would be able to compensate for the lack of storage unit.

Valliant ecoTEC plus combination store 938 and viessmann 111-W and 222-F both have a storage however I am aware the work differently.

There is highflow 440cdi or 550cdi there as alternative option if you believe that is better.

I have been thinking of 222-F as it has around 100 litre storage, it seem to superior to 111-W however it is twice the price and I am not sure if the price justify its quality. I am aware after the storage depleted it takes about 10-20 min for the tank to heat up and the flow rate revert back to 14 L/M but thats still better than what I get now.

I have heard they are different models of 222-F, are there any model I have to avoid or look for?
Are they worth the price? Do you think 222-F is suitable for our house or should I go for one of the cheaper models? are they as reliable as their manufacture claims? are their customer service good if something does go wrong? is 222-F compatible with NEST, is it even needed as it has its own app?

I am also going to install magnaclean pro 2 and power flush the system and put cleaner and inhibitor products to make sure the warranty doesn't get voided.

Read more: Viessmann/Worcester/vaillant any information would be greatly appreciated! - https://www.diynot.com/diy/threads/viessmann-worcester-vaillant-any-information-would-be-greatly-appreciated.559803/#ixzz6hAMF5spS

 

[Scott_D]

A combi is totally wrong for the property

Have you tested incoming flow and pressure?
Have you found an installer you like?

 

[Ben-gee]

5 bed , 4 bath house with 20 radiators and you say there is no room for a boiler and a cylinder? Must be a poorly designed house?

 

[gmartine]

Wrong, wrong and more wrong...four bathrooms serviced by one combi? Absolutely ridiculous, spend 10k on semi commercial system as it will future proof your house for years to come.


Funny how the datum for this potentially expensive upgrade/renovation is the insistant use of monsoon shower heads. Dam advertising with that chick in the rainforest washing her hair. Change them, they are a complete and utter waste of water and energy and besides you haven't done the most basic research which is to see as Scott has mentioned if you have adequate incoming pressure and flow for any combi boiler upgrade let alone a 50kw combi which is frankly verging on the ridiculous. Find a good engineer, despite your research pouring over these forum pages you do not have the knowledge, most engineers will do exactly what you want and be wary of those that don't question your choices.

 

[Riley]

Cylinder all the way. Not at all what a combi is designed for

 

[cjg]

it also depends on how your hot water/cold is piped round the house, if its all on 15mm theres no chance of
running bath +shower with out drop, fit a tank and pos repipe to suit, would also do hw circulation,.

 

[king of pipes]

I'm afraid the chaps have got it right you will need a cylinder and seperate boiler system to supply a large family property, zoned heating and timing of hot water demand will determine boiler size but your looking at 35 kw + in the winter months , a decent mains cold water supply and pressure is needed i suggest you employ a local Gsi to advise you further , a large combi is not the way to go. Regards kop

 

[cjg]

as above, and i would look at Viessmann system boilers,

 

[Ric2013]

I am writing from Italy where storage combis are very common. They are better than a real combi, but still have limited flow, or at least my experience is that as flow increases, the temperature still starts to fall.

I like the idea of a combi. No stored heat losses and instant hot water. Would work well in my two bedroom terraced house (the slight trade off being not having 20l/m to fill my bath very quickly, but I can live with that).

In saying 'flow is a big thing for me', however, you are ruling out a combi. 6l/m is a perfectly respectable shower, but not if you have showerheads requiring 18l/m. FWIW, I have fitted power showers that only go up to 14, so 18 is a heck of a lot! A 100l storage combi may not be much smaller than a system boiler and separate cylinder (whether that be vented or unvented).

If you MUST have a combi, then you have answered your own question. If your house is underoccupied, have you considered a combi plus a cylinder? Then you can use the combi for one bathroom in day-to-day use, and feed the other bathrooms from the cylinder, only heating the cylinder when required.

Having looked at your DIYnot question, I wonder if you are aware that there are two issues here? One is the maximum flow to your house and through your combi. The other is the maximum flow thorough your combi at a useful temperature. You may find you get 20l/m through your combi but that the combi is unable to keep it at a useful temperature in winter. The rating is often stated as x l/m at a y°C temperature increase.

If a mains upgrade is truly expensive, another option is an old-fashioned cold water storage cistern and pumped flow from a vented cylinder. Sometimes the old ways are still valid. The cistern will refill as and when the mains flow minus competing uses allows (acting as a buffer) and you use the water at the maximum rate your internal plumbing (pipework, showers and pumps) is capable of.