Huge house, 4 bath, Vitodens 222-F storage combi or other

[DrTooth]

ok so I am building my house.

I have decided to install a viessmann boiler, I have 4 bathrooms and 600m2 of under floor heating.

I was planning to install a 222-F storage combi but after talking to ********************* (They sounded really really knowledgeable) they have now started to swing my opinion towards a normal system boiler with a cylinder.

I want to be able to run at least 2 or 3 showers without running out of water, we plan to have rain showers in each bathroom.

I would like to hear peoples thoughts on this.

 

[ALEC1]

Your problem is going to be getting the flow in to the house...

I would calculate the flow rate you need and work back wards..

a 35 kw boiler will reheat at about 12 litters/minute plus you have a store of 130 litres with the 222

at the end of the day this type of thing is a mathematical task, not a plumbing issue...

 

[SpecialK]

You should just install whatever ***************** suggest as they are indeed really knowledgeable about Viessmann systems.

 

[dcawkwell]

System boiler (possibly two small ones in cascade)
Unvented cylinder (possibly two smaller ones spread through house near
to demand)
Depending on flow into house. Cold accumulator tank

Where is the house?

 

[holty]

one way to get more usage out of your hot water would be to use a whole house tmv. off the 222. and this was advised by viessmann by the way. good boiler fast recovery time. yet i would still go with cylinder and 200w setup.
but must admit dcawkwell idea is a good setup. end of the day your asking people who cant see the job. it should be the company you employ to tell you what is best for your property. by the way look at the rinnai twinflow. excellent piece of kit. and probably my first choice.

 

[Corgigrouch]

Combis have their place and their uses and in my opinion they should never be seen in large homes with multiple bathrooms, irrespective of how clever the combi set up is. To this end I too agree with dcawkwell

 

[snb]

to supply 4 showers you will definately need an accumulator and at least a 300lt cylinder or maybe better with 2 smaller cylinders.

You are unlikely to have a mains cold supply that can deliver 60 to 80 lt/min which is what you need for all 4 showers to work at once.

Most mains supplies even the best only achieve 35 lt/min

Before you go any further i would just ask what flow rate checks they have done.

Without the an accumulator you are unlikely to be able to run more than 2 showers without a flow rate reduction.

 

[Norcon]

600m2 of under floor heating will need careful thought.
A commercial style controller with all the trimmings hooked up to two mixing valves split between upstairs and downstairs or between living and bedroom areas would be a start.
With a few manifold actuaters holding off certain rooms on a timer.
60kw boiler/s minimum.

 

[transam]

We got involved with a similar set up recently 2x baths + showers
1x bath &

2 x showers with body jets & a rain shower head size of a dustbin lid hans grohe thing , capable of 35 + ?? litres a minute ?? give or take ?

6 x shower/bathrooms in total.

Only problem with it , is the waste on the shower tray can only cope with 20 litres a min shallow depth one as well

( we never speced any of the kit ) all un - vented

 

[Agile]

Sounds like yet another "promote ****************** thread!

He has a nice web site and is qualified to work on several different gas categories including LPG and some commercial.


With a larger property its always a good idea to be very careful to ensure the design is correct as its impossible/expensive if under floor heating does not work properly.

Its also important to decide how many bathrooms you want to operate at the same time. If its all four then you will need a large water storage tank and pressurisation pump.

 

[ChrisR]

3 rain showers, 35 l/min each, say 10 minutes. No problem. That's a tonne of water so support the 4 unvented cylinders it'll need quite well, as well as the couple of tonnes of cold in break tanks, and the couple of inverter driven multistage pumps.
100kW of boiler should have it all hot again in about half an hour - as long as the heating's off

 

[doitall]

I think Chris was being a bit tongue in cheek.

The project needs designing by an expert.

What Tony said about being spam for ************** is the best answer, and I agree with him.

************ sounded really knowledgeable

then the OP feels the need to ask advice on a DIY forum

 

[Agile]

You should just install whatever ********************* suggest as they are indeed really knowledgeable about Viessmann systems.

Its odd though that ************* posting also supports the supposition that its a ************spam!

*************is run by a ******* !

Perhaps "*********** is really the same ********************* ?

 

[DrTooth]

Thanks for all the info.

we have a 34mm cold water supply coming into the apartment (its not a house but a flat on one floor).

I have asked my plumber to look into it some more. He is going to see if the Viessmann rep will come and have a look around and suggest if he thinks its a good idea to use the Comb but the more I think about it he more I think we will just go with a cylinder system.

My understanding is that he plans to use a 4 pipe system, run a secondary supply and 28mm pipes to each manifold in the bathrooms.

Ideally I would like to be able to run 3 showers at the same time.

With regards to the P K Plumbing comment, I am not connected to them at all, they will not be installing my system because I am located in in the midlands and PK are in Reading. I just called them for a price on the boiler and the guy was nice enough to spend 20 min on the phone with me giving me some advice and suggestions.

We are using this company ********************* as we had originally planned to use air source heat pumps. They have been incredibly helpful and when it comes to renewable energy he REALLY knows his stuff.

 

[doitall]

Ok benefit of the doubt.

One boiler is stupid for a large property, as is any combi boiler.

If you can't get more than 50Ltrs/min out of the mains at peak times, you'll need a break tank and pump set (can be in an out building/plant room with a large unvented cylinder and the boilers.)

If you have a large open area, ground source heat pump would be much more energy efficient.