tips for radiators

d o'c

I'll soon be connecting my new radiators, I'm planning going with plastic piping. The pipes will go under screed, be chased up the wall just above skirting level, then out to the rad valves

So I'm thinking I'll have to switch to copper just before the pipe comes through the wall. I'm hoping to hide the joint behind the skirting board,so if i ever have a leak i can acess it without ripping up the screed.

Whats the most common joint to use for the changeover, push-fit or compression?

appreciate any pointers, thanks.

Pete67

Personally I would use compression fittings with the correct insert in the pipe.

My tips - watch the minimum bend radius with Qualpex or other plastic pipes, I have seen more than one kinked so badly due to bending too tightly that it cuts off all flow to the radiator. While it might appear OK when cold, the material softens when heated and can collapse then. Also use barrier pipe for CH systems to prevent oxygenation of the CH water which can lead to corroded radiators.

d o'c

Pete67 wrote: »

Personally I would use compression fittings with the correct insert in the pipe.

My tips - watch the minimum bend radius with Qualpex or other plastic pipes, I have seen more than one kinked so badly due to bending too tightly that it cuts off all flow to the radiator. While it might appear OK when cold, the material softens when heated and can collapse then. Also use barrier pipe for CH systems to prevent oxygenation of the CH water which can lead to corroded radiators.

thanks for the tips, appreciated:)

Joey the lips

Make sure if your using pex under the concrete that its shielded. Concrete eats through it.

Micky Dolenz

I'd be up for using compression fittings too, I just don't trust most push on fittings any more.

Pete is absolutely correct, plastic pipe "waves" and bends when hot so be aware of this.

glenkeo

Hi d o'c
My plumber used chrome fitting between rad and pipe in the wall with some kind of compressed fitting on the end. They look a lot better than the copper pipe and I but a plastic chrome ring around any coming out through tiles in the bathrooms.

d o'c

I'm thinking now of going with pex in conduit.
the expansion rate of pex i think is around 1%, so a 6m pipe will move 6mm
and I'll probably run rads off manifolds.

would it be wise to have a non rigid fixing for the manifolds to allow movement?

Carlow52

d o'c wrote: »

I'm thinking now of going with pex in conduit.
the expansion rate of pex i think is around 1%, so a 6m pipe will move 6mm
and I'll probably run rads off manifolds.

would it be wise to have a non rigid fixing for the manifolds to allow movement?

6m = 6000 mm => 1% = 60 mm

better let the plex move rather than fooloing around with flexible connections

I'll soon be connecting my new radiators, I'm planning going with plastic piping. The pipes will go under screed, be chased up the wall just above skirting level, then out to the rad valves

So I'm thinking I'll have to switch to copper just before the pipe comes through the wall. I'm hoping to hide the joint behind the skirting board,so if i ever have a leak i can acess it without ripping up the screed.

Whats the most common joint to use for the changeover, push-fit or compression?

appreciate any pointers, thanks.

the plex wont take a short radius 90 degree bend like u propose here as explained by the earlier posts so u will have 2 joints

heinbloed

D o'c wrote:

the expansion rate of pex i think is around 1%, so a 6m pipe will move 6mm

Well, my UFH circuits would have separated from the groups a long time ago....

Check the manufacturer's data sheet again. Calculate the expansion for the real DeltaTK, the real difference between minimum and maximum thermal exposure.

Plastic is - as it's name says - plastic. It moves in all directions with changing temperatures. So a strain or push due to temperature changes will be made-up by side movements - if installed between two fixed points.

d o'c

Carlow52 wrote: »

6m = 6000 mm => 1% = 60 mm

Yes I missed a decimal place there:)

1% is recommended for pipe installed at 20C that may go to 82c
60mm seems a lot over 6metre length.

will obviously be less for lower temp UFH.


I thinking the pex in conduit will more prone to pulling pushing compared to pex direct in cement where the cement would clamp it better?

heinbloed

I thinking the pex in conduit will more prone to pulling pushing compared to pex direct in cement where the cement would clamp it better?

Indeed.
With dry UFH systems one can hear the PEX moving when the heat is turned on or off. Not so if packed into conrete.