DIY Forum

 

Ultimate Handyman Ultimate Handyman Ultimate Handyman Ultimate HandymanUltimate Handyman on Pinterest

 

DIY Forum/Home improvement advice forum

 

 

A-Z CONTENTS | DISCLAIMER | DIY VIDEO | HOME | SAFETY FIRST | FORUM RULES

It is currently Tue Oct 17, 2017 1:04 am
Visit Thermo worx


Time zone: Europe/London [ DST ]




 

 


Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Sun Sep 10, 2017 5:35 pm 
Offline
Newly registered Member

Joined: Sun Sep 10, 2017 5:24 pm
Posts: 2
Has thanked: 0 times
Been thanked: 0 times
Hello!
I am getting conflicting information so would like someone in the no to point me in the right direction!

I have a Bosch 25kw external oil boiler. The central heating in my house is all 15mm pipe (reduced from 22 about a meter from boiler).
I have built a 2 story extension which i habe roughly calculated will need 7kws worth of rads. Current system is 11kw.
Now.....i understand that the CH should be 22mm flow and return with 15mm coming off to the rads. Whoever installed my system hasnt done that!
Can i use 15mm in extension and connect to existing?
Should i use 22mm in extension? Will this cause flow/balancing issues when connecting to existing?
Do i need to change current set up to 22mm (worst case as ceilings down in current house!).

Or are there any other options?

Thanks.


Share on FacebookShare on TwitterShare on DiggShare on DeliciousShare on Google+
Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 10, 2017 9:08 pm 
Offline
Senior Member

Joined: Mon Apr 13, 2009 8:03 pm
Posts: 6223
Has thanked: 695 times
Been thanked: 718 times
In a perfect world the existing pipe work would be changed to 22mm.

15mm will carry around 4kw of heat adequately, whilst 22mm is rated around 18Kw.

_________________
Dave

www.drlgas.co.uk


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 10, 2017 9:18 pm 
Offline
Newly registered Member

Joined: Sun Sep 10, 2017 5:24 pm
Posts: 2
Has thanked: 0 times
Been thanked: 0 times
Dave

Thanks for your reply. When you say about the kw capacity of both 15 and 22mm is that for a certain length? Or in general? The only reason i ask is that the current house system is completely 15mm and my rads total 11kw (calculated using sizes).

Sorry if i have misunderstood

Thanks again.


Top
 Profile  
Reply with quote  
PostPosted: Sun Sep 10, 2017 10:16 pm 
Offline
Senior Member

Joined: Mon Apr 13, 2009 8:03 pm
Posts: 6223
Has thanked: 695 times
Been thanked: 718 times
If you had really long pipe runs then I suppose technically you would go up a size, I am not that clever to work these type of things out, but in your average domestic set up the length of the pipe runs wouldn't really come in to it.

Undersized pipes may well still let the rads get hot, but may take a lot longer to do so.

If one is to be technical, then the temperature difference between flow and return back at the boiler would also be a factor in working pipe sizing out as well. e.g. whether it is a condensing boiler (20c) or standard boiler (11c)

_________________
Dave

www.drlgas.co.uk


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 


Similar topics
   

Time zone: Europe/London [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Visit Hilti


 

 

 

News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list
ultimatehandyman privacy policy

Contact

 

Powered by phpBB® Forum Software © phpBB Group

phpBB SEO