22mm pipe to all rads .... OVERKILL??

[Vladimir]

Hi

Working on a house that has only 6 rads that are relatively close together.

There is 22mm pipe running everywhere to all the rads with the tee reducing to 15mm at each rad - feed and return. Is this needed? I thought 15mm for all the rad runs would be enough?

Whadya think - OVERKILL?

V

 

[breezer]

probably is, but if it aint broke, dont fix it

 

[Vladimir]

probably is, but if it aint broke, dont fix it

Well it kinda is broke and Im replacing the pipes ... so do I replace with 22 or will 15 do?

PS Vladimir is a little-heard-of Welsh name indeed!

V

 

[Slugbabydotcom]

Now you just can't beat a bit of MOTORHEAD

About the system tho. It could have been designed as a gravity system which is fairly unusual. Tell us more about the system!

Either that or someone got a cheap job lot of 22 pipe off the back of a wagon.

I'm a member of the if it ain't broke dont fix it brigade too . How is it kinda broke? it either works or it doesnt!

You will need some 22 if you are replacing all of the pipes

 

[Vladimir]

Okey Doke Diddley Dokily

Ermm...

Am replacing pipework cos its all old and stuff with corroded scary looking old compression fittings

About the system:
Its a pressure system (red pressure vessel above boiler). One Indirect cylinder and six rads. Boiler is about 50000 BTU I think.

I have a load of 15mm piping you see and loadsa 15mm fittings but I fear there is some unknown reason that the existing pipe is 22mm.

Continued thanks etc

V

 

[kevplumb]

depends on the size of the rads

 

[DP]

Now this post looks like a wind up. Surley if the fitting is scary looking corroded type, why not undo it, clean it and remake? To repipe (because you have 15mm pipe) would suggest you are trying to create work for yourself.

Not the first time I have gone to an installation that was plumbed in 15 to find some rads did not heat up. One I went to some time ago had an Excell 20Kw on the wall and 15mm connected to isolating valves, then 15mm tee to two branches (upstairs and downstairs). 5 rads on ground floor with one (on long line and a biggie) refused to heat the room.

 

[Slugbabydotcom]

Do you plan on laying a laminate floor over a wooden floor which has pipes underneath?
Are you mysteriously losing pressure?

Common practice is to run 22 pipes from boiler to tee pieces which splits both of these into two lots 15 pipes each pair feeding 3 rads. You could split it 2-4 rads or even 1-5 but dont let much more than about 30000 btu worth [9 kw] of rads run on 15 mm pipe.
There are calculations and stuff you could look up but for only 6 rads it's really not worth the chew.
Using copper? dont forget to clean the flux off after soldering, do not allow the copper any contact with concrete or disimilar metals and remember to insulate pipes.

 

[PEDANTICVINDICTIVEMAN]

Sounds to me like a one pipe system, if it is and you are replacing it with a two pipe system, start from boiler in 22mm and then reduce down to 15mm for last four rads, if the boiler is sized correctly for the property at 50,000btu it will be fine.