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Mar 10, 2018
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Scotland
Member Type
DIY or Homeowner
Hi,

I recently purchased a cottage type bungalow and currently there is no central heating in the house only electric storage heaters.
I am in the process of removing all the storage heaters and installing the new central heating.
All the floors in the house are cement and all the exterior and internal walls are full of king span or glass wool insulation. Making it a real headache to get pipes to the radiators.

My plan at the moment is to run 22mm flow and return from the boiler into the loft space to 22 x 10mm manifolds and drop feed the radiators down behind the walls and then behind skirting boards and up to the Rads. Most of the Rads will be underneath windows. All runs of 10mm pipe will be +/- 5m flow and 5m return back to the manifold. The largest radiator in the house will be 1100 x 600 double, 8 x Rads in total.

I also plan to fit an indirect unvented cylinder in the loft space and pipe the coil in 15mm.
Central heating boiler is a Firebird enviromax outdoor oil boiler.

I know a lot of people don’t like to use 10mm for central heating but seems to be my only option without channelling the cement floors.

I have recently read that a lot of new build houses central heating systems are done a similar type way. Do you guys think what I have described will work OK with the length of runs of the 10mm pipe?


Thanks in Advance
 
As above, for the safety of yourself, your family & your neighbours, please get someone who is G3 qualified to fit the unvented cylinder.

With regards to the piping, if I was in your position I would go for 15mm and channel the floor if need be. Seems a shame to go to all this effort only to stand an increased risk of blockages and issues further down the line that will be expensive & disruptive to fix.

Also as a general rule of thumb, anything that is common practice in new builds is almost certainly not best practice.
 
Appreciate the reply's.
For sure I will have qualified Plumber to fit the boiler and cylinder.
My plan to reduce cost was to rough in all the pipework and have a plumber do the final install.

Agreed 15mm would be much better than 10mm.
But do you think it is possible from what I described for the system to work OK if well maintained and plenty inhibitor?

Thanks
 
It will work if executed properly alot of new builds are done that way the boiler and unvented cylinder are notifiable so will need fitted by a registered installer , any work you carry out yourself will need checking and pressure testing . Kop
 
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Appreciate the reply's.
For sure I will have qualified Plumber to fit the boiler and cylinder.
My plan to reduce cost was to rough in all the pipework and have a plumber do the final install.

Agreed 15mm would be much better than 10mm.
But do you think it is possible from what I described for the system to work OK if well maintained and plenty inhibitor?

Thanks
No matter how much you ask us Mr1981 ...you will get the same general reply ...22mm main supply and 15mm to the rads. Plus the visual effect of microbore to the rads and anywhere seen ...immediately
says old, amateur , skin flint
cheap etc. if you will want to extend or sell on your plans for
microbore are plain wrong.
centralheatking
 
Don't forget to forget to run you 15mm Hep2o or Speedfit in conduit to protect it in the floors & then have a 90 degree fitting & bring it up in 15mm copper.

Looks a lot better than other options.

Andy
 
Why not just use plastic coated copper in the floor. Denso tape all the joints, will last forever.
Make sure you make up your rads and measure from centre to centre of your valves for your first fix otherwise will look carp

Or better to have the rads screwed to walls first and pipe to them, if possible
 
I always make/purchase a conduit box for any joint in floor as putting joints into concrete is bonkers, will always bite you on the arse later on
 
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Thanks for the feedback.
Will take onboard and may go with channeling floors for 15mm, also good to know that the 10mm systems can work.

Cheers
Why not using 12mm coiled copper (internal diameter 10mm) you can run it easily behind the skirting board, maybe a bit hard but not impossible to find it.
I used even 15mm behind skirting board and soldered just under the radiators 30-35 cm of 10mm und run it all in one piece trough chased wall to the valve as you can see in the pic

radiator .JPG
 
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Why not using 12mm coiled copper (internal diameter 10mm) you can run it easily behind the skirting board, maybe a bit hard but not impossible to find it.
I used even 15mm behind skirting board and soldered just under the radiators 30-35 cm of 10mm und run it all in one piece trough chased wall to the valve as you can see in the pic

View attachment 37763

Looks good.

Cheers
 
I've got a house with 10mm radiator feeds. Have had blockages in the past, and change the corrosion inhibitor regularly. If I was building from scratch I would follow everyone's advice here and go 15mm. Think about what you want down the line, in 10, 20 years time.
 
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Used 10mm a lot, never had problems. Our house is 8mm, 20 years plus, (remember Servowarm?) works a treat.
oohh Servowarm ...gasinspect,
thats a blast from the past...
for the younger ones on here
it was a well promoted Ng central heating system in the 70's. about 15kw no mains connection just a top,up bottle
and the ...Master Radiator ..which was in fact the boiler which fed the rest of the system
but looked just like a radiator and was hinged to allow access to the boiler...yes my dad had one instalked in about 1968
remeber it well
centralheatking
 
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Reactions: Pickwickpick
oohh Servowarm ...gasinspect,
thats a blast from the past...
for the younger ones on here
it was a well promoted Ng central heating system in the 70's. about 15kw no mains connection just a top,up bottle
and the ...Master Radiator ..which was in fact the boiler which fed the rest of the system
but looked just like a radiator and was hinged to allow access to the boiler...yes my dad had one instalked in about 1968
remeber it well
centralheatking
Good: Doesn't allow fluids to mix.

Bad: Forces and empty gap between pipes.

Solution: Automatically use Flow Control's directed pipes to keep pipes pointed away even when next to each other.
 
Nothing wrong with 10mm to rads......as long as the runs ain't really long and the rad isn't a massive double! Do tonnes of system with 10mm. Although 15mm is better....a well protected and flushed 10mm system is perfectly fine.
 
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Nothing wrong with 10mm to rads....as long as the runs ain't really long and the rad isn't a massive double! Do tonnes of system with 10mm. Although 15mm is better....a well protected and flushed 10mm system is perfectly fine.


Thanks for reply.
If I decided to go with 10mm pipe what would you recommend for max pipe runs? At the moment would be about 5m flow and return (10m total) to manifold 3 x double rads are 2.2Kw the other 5 x rads are all small.

Thanks
 
He is dropping pipes inside walls,so take it to outlet behind radiator and sweep down into chrome 10mm push fit elbows (screwfix] ,no joints in walls, very neat, hardly see any pipe at all, and clear floor for easy cleaning.
 
Thanks for reply.
If I decided to go with 10mm pipe what would you recommend for max pipe runs? At the moment would be about 5m flow and return (10m total) to manifold 3 x double rads are 2.2Kw the other 5 x rads are all small.

Thanks


What size are your double rads?
 
He is dropping pipes inside walls,so take it to outlet behind radiator and sweep down into chrome 10mm push fit elbows (screwfix] ,no joints in walls, very neat, hardly see any pipe at all, and clear floor for easy cleaning.

This is the best method, very tidy, plus stops the missus from bashing the pipe with the hoover. It’s what I’ve had for the last 15 years, as long as it’s fit right and flushed right then dosed with the right amount of inhibitor.... happy days.
 

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