what size pipe for central heating ?

[rulo]

Hi there can any one advise me on the size of copper pipe to use for a new central heating (rads and boiler)system. Im aware that 22ml needs to be used from the boiler (combi) and someone said then it could all be in 15ml (to all rads.) But i have read it should be flow and return in 22ml branching off to the rads in 15ml . Obviously the first option would be cheeper to do and easier ( i am a first attempter) But i do want it to work properly. Also i havnt bought a boiler yet so would the first option need a larger output btu to compensate ? thanks for any advice.

 

[Simon F]

if the complete system is not properly sized, you will probably have issues with some radiators being to hot others to cold. some parts of the house could be to hot other areas not hot enough etc. If the boiler is not sized correctly it will not be working to the best efficiency. depending on the boiler and system type there may well be safety issues that are overlooked.
the size of pipes will depend on the amount of heat that you need to supply to the radiators feeding of the pipes. if you try to cut costs at this stage you likely will pay more in the long run.
there is no simple answer, other than to get someone in who can legally do the work and give you the advise specific to you property.

 

[PlumbBobBob]

in all honesty if you haven't done anything like this before you will struggle to do it correctly. i would get the gas engineer who will be installing your boiler to do the whole thing.

that's always you will be getting an engineer and not doing it yourself which is illegal.

 

[AWheating]

http://www.worcester-bosch.co.uk/cache/file/17/pipework-sizing-guide.pdf

 

[Simon F]

not to forget also are the new zoning requirements, which depends on the shape of the house and route the pipes will take, quite likely will affect the way pipe runs need to be designed to comply with the new regulations.

 

[rulo]

Thanks for your response.. i have found a web page to help calculate the sizing. I intend to do the reverse return plumbing method as this is a self -balancing system and have done all the other calculations . I just couldnt find any info on pipe sizing .I'im not going to do any illegal work ,(as a few seem to be worried about) just doing as much as i can then getting it checked and connected to gas by an engineer.

 

[tamz]

Bit over kill doing a reverse return on a domestic house but whatever floats your boat.

 

[rulo]

Hi im trying to get some help here, thats why im on a forrum, just trying to read up on what to do ,if its over kill ill think again .

 

[dontknowitall]

Generally it's a 22mm pipe forming a flow from the boiler to create a heating circuit and returning to return in the boiler.

Off this you'll have 15mm (preferably) or 10mm. One pipe attaches to flow and goes to trv and other pipe comes from lockshield to return.

Bear in mind that there are a multitude of variances on this theme and I'm blown if I'm going to go through them all!!

 

[Howsie]

How bigs the house and how many rads and what size?

 

[plumman]

This site is Madness, im going now to make a rocket to fly to the moon bye!

 

[tamz]

Never heard this one for years thanks
[video=youtube;SOJSM46nWwo]http://www.youtube.com/watch?v=SOJSM46nWwo&feature=related[/video]

 

[rulo]

The house is a terrace with 3 beds (one being in the attic/ new conversion) there are 9 rads (and only 1 bathroom with seperate shower) I have calculated the total wattage to be 17 (14 for rads +10% + 2-3 for dhw) though im understanding that this doesnt relate to a combi boiler ?????? .as the houses next door have both 24kw and 30kw combis. (this is a renovation project so im starting from scratch no boiler/pipework at all). My queery on th pipe work was sizing , i am doing the flow and return in 22ml.. and off that to the rads in 15 ml ; its just the length of some of the 15ml pipe take offs are up to 5m long does this sound ok or do i need to lengthen the 22ml circuit ?(though the rads are relitavely small ones)all will have lockshields and trvs bar 1 .cheers

 

[Gray0689]

5m is fine no problem at all

 

[SimonG]

I'd be running 22 to manifolds and 10 to the rads. With two sets of manifolds, one for bedrooms and one for living areas.

 

[Gray0689]

I'd be running 22 to manifolds and 10 to the rads. With two sets of manifolds, one for bedrooms and one for living areas.

Yes that's the way if doing it with manifolds ( but I still use 15mm to rads with manifolds but that's just me)

 

[AWheating]

if rads are more than 5m away from manifolds then 15mm would be a good idea.

 

[rulo]

thanks im getting there!