C/Heating Pipework

[robsartain]

I have a boiler with 22mm out/return connections. Radiators are 15mm, do I want to run as much 22mm pipework to the rads as possible beofre I reduce down or doesn`t it matter ?

Obviousily being tight 15mm copper pipe costs less :-)

Any thoughts please.

P.S Its a standard 2 up 2 down terrace.

[robinhood21]

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

[dirkgently]

robsartain said:

I have a boiler with 22mm out/return connections. Radiators are 15mm, do I want to run as much 22mm pipework to the rads as possible beofre I reduce down or doesn`t it matter ?

Obviousily being tight 15mm copper pipe costs less :-)

Any thoughts please.

P.S Its a standard 2 up 2 down terrace.

Rule of thumb, 15mm pipe can supply 3kW of heat of find the kW output of your rads and go from there.

[B17NNS]

22mm from boiler (or tank), branch off flow and returns to rads in 15mm

Edited by B17NNS on Wednesday 28th October 19:57

[jonnyye]

robinhood21 said:

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

Oh dear , please dont post "advice " when you obviously have no idea whatsoever

[robinhood21]

jonnyye said:

robinhood21 said:

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

Oh dear , please dont post "advice " when you obviously have no idea whatsoever

?
Without having floor plans etc 'tis the best advice to give.

[Arthur Jackson]

jonnyye said:

robinhood21 said:

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

Oh dear , please dont post "advice " when you obviously have no idea whatsoever

Believe me, if stay here and keep reading 'heating' threads you'll feel like posting this response so often you'll just give up. I'm amazed dirk is still sane.....

[Simpo Two]

Problem is, it's sometimes hard to tell who's a professional plumber/CH bod and who is a DIYer.

If professional plumbers/CH bods could make us aware of their expertise by putting 'professional plumber/CH bod' etc in their profile then it would help readers know who to believe and who to ignore.

[dirkgently]

robinhood21 said:

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

Using small pipe sizes requires higher pump pressures.
Higher pump pressure causes more system noise.
In a domestic system 5Kg/sec is about the maximum flow rate you can achieve without undue system noise.
As calculating the pipe resistance heat-loss ect for every 2 bedroom semi would be time consuming and fairly pointless, 3kw per 15mm run is a good rule of thumb.
Hope that makes sense.

[King Herald]

jonnyye said:

robinhood21 said:

You really should keep the flow and return runs in 22mm, only branching off with 15mm to each rad. If you branch off into 15mm to supply more than one rad you will have problems with sufficient heat supplying both rads. Could also create problems with undue stress on the pump.

Oh dear , please dont post "advice " when you obviously have no idea whatsoever

I'm glad you have arrived jonnnnyyye, as now we obviously have a fully qualified plumber on the forum giving useful and expert advice. No more useless answers from people who obviously have no idea.....

[robsartain]

Thanks for the help guys.

Basically I have 4 rads all of 1000mm x 600mm that give out 3536 BTU which is 1036w. So 2 rads under the 3KW limit. So if I use 22mm pipework until I tee off for upstairs and downstairs then I should be fine.

I know there are a lot of heating questions but there are also a lot of electrical, roofing, etc.... why can`t there be some FAQ or how to guides which hopefully will eliminate the repeation and as further questions get asked these guides get added to ??

Personally I always do a search before posting to see if I can find a similar thread.

Also I like the idea of people putting there specialist trade down, so you can rate replies.

Thanks

[shirt]

i'm not a plumber but i do occasionally design piping feeds and fitted my own GCH [bar the boiler obv.]

keep it 22mm. larger bore = less losses in the system and less work for the pumpt to do. its also much more flexible for future upgrades. for some reason i also find 22mm easier to work with.

you'll get pro answers i'm sure, but to address your 'how to' idea maybe try a DIY forum! screwfix one is ok for this[good advice but some right knobheads giving it].