New boiler new system

[Davidalexjeffs]

Hi all,

Ive got a 40kw Ideal Vogue combination boiler going into a new 4 floor Georgia terrace, with big ceiling heights and subsequent flow and return runs.

The boiler is being installed at basement level so I want to understand the heating requirements and pipe sizing for the flow and returns.

I plan to run 22mm f/r’s up all x4 floors where we will branch off in 22mm to serve rads on each floor. Given the size of runs to the rads, how much 22mm should be run up to the radiators? Can I get away with 15mm piping to the radiators say 6-8m away from the 22mm f/r feeds?
Or would you pipe the rads all the way up the last tee and a small 15mm tail to the rad?

Im worried about pump performace and getting heat to the very top floor. Which is around 12-14m height from the basement boiler.

Or do I run 22mm to the very top floor up to the rads and then on the floors below, have longer 15mm runs?

Do I need to fit an AAV on the top flow/return pipe?

Or am I overthinking the whole thing?

 

[Riley]

Are you the installer?
Have the correct Heatloss calculations been carried out?
Why no mention of zoning??

 

[Rob Foster]

I have experience if Georgian homes , both fitting in and living in when I lived in Bath for 2o years. Beware the heat loss calculations generaly will result in inadequate heat all round the house. If its listed then leaky sash windows wont help. if you want advice over leaky windows I can help.
Generally its 22mm most of the way, even 28 off boiler for the vertical runs to 1st maybe 2nd floor. then 22mm then 15 mm for each pair if rads maybe 3 if they are little ones...never try more than 3 or 4 kw off 15mm
Zoning is essential , be carefull where you stick the boiler the flue might attract criticism or look ugly on your nice georgian facade. Ceiling heights are also an issue regarding heat calculations. Get someone like british gas to do you a quotation and design, but dont waste an honest outfits time its not fair. Let us know hiw you get on. Rob Foster aka centralheatking

 

[Davidalexjeffs]

Heat loss calulations complete for correct radiator sizing

Zoning of system through digital TRVs Drayton Wiser
Customer did not want 2 ports?!

Thanks for your reply-28mm f/r piping is a good shout and 22mm most of the way to the rads.

Any other things to take into account?

 

[Scott_D]

How many rads?
Is the pump up to it?
Additional expansion?

 

[Riley]

Secondary heating pump
Expansion
How many bathrooms?

 

[Rob Foster]

Riley is dead right the volume of water might be too much for the expansion so bung another on somewhere convenient, more the one bathroom and ensuite you will not get enought hot water and if a big bath the heating will divert to hotwater for ages ....let us know much more or you might be designing yourself into a big cold dessert
Rob Foster aka centralheatking
also remember geogian buildings dont have cavity walls but solid stone on the front and crappy back fill behind if your lucky, some are just 6 inch limestone and thats it

Secondary heating pump
Expansion
How many bathrooms?

 

[Davidalexjeffs]

We have x10 rads and only one bath and one electric shower.
We tried to convince the customer to go unvented with zones but he wasnt keen!

So we dont have too many rads on the system. They require 60,000 BTUs so only 17.6kw needed from boiler heating output
I dont think an added expansion vessel or pump would be needed given its only x10 average sized rads (750x1200 K2)

 

[Rob Foster]

17 kw ...how many rooms ? !
christ my gaff is three floors 3 bathrooms 5 bedrooms and a big open vaulted extension roof (not heated in winter itsca summervroom but has 6 kw for xmas ) the house is fully insulated and I throw 30kw at it at peak ...we are nice and toasty when it is chilly and guess what I can always turn it down Rob Foster aka centralheatking

 

[Aire]

17 kw ...how many rooms ? !
christ my gaff is three floors 3 bathrooms 5 bedrooms and a big open vaulted extension roof (not heated in winter itsca summervroom but has 6 kw for xmas ) the house is fully insulated and I throw 30kw at it at peak ...we are nice and toasty when it is chilly and guess what I can always turn it down Rob Foster aka centralheatking

That's great Rob, but the size of your house has no relevance to op's question so I fail to see why you felt the need to mention it

 

[Rob Foster]

That's great Rob, but the size of your house has no relevance to op's question so I fail to see why you felt the need to mention it

it seemed to me that they were similar 4 floors high ceilings
and op is not putting enough beans into the place ..in my opinion ..thats why ..why not give my opinion chking I think he is making a mistake and dont want to see him battered anyway lets see what the collective wisdom is...we have done loads of these types of props. but I cannot remember the kw stuff always for each of these jobs over 30 + years x 2o fellas would you ? all I know we got it right
most of the time

 

[Jones82]

Additional expansion vessel will be necessary due to the head / pressure pushing onto the boiler in the basement, 14m of head = 1.5 bar of pressure before you even turn the heating on!

 

[king of pipes]

My advice for what it's worth is it not the right boiler for the property ? but if I was doing it I would install a low loss header off the boiler and zone each floor, use the combination hot water side for the low floor hot outlets , and install a pressurised hot water cylinder central to the property for the rest , 28mm heating pipework flow and return with 22mm branches for each floor with zone valve for each and you will need a good size pump to push the heating up to the top floor the Vogue will struggle have my doubts it will even do it and you will definitely need a additional expansion vessel , time for a rethink bud . Cheers Kop