15MM central heating pipes

[Barter78]

I’ve been taking a few more quotes in and ther overall consensus is pretty much 50/50 from the tradesman that have come…

I’m going to install the boiler and rads and take it from there, if I need to change pipes I’ll do it after seeing how it runs…

The main concern seems to be balancing….

Fingers crossed

 

[Barter78]

Ok… just an update - the trades person installing everything has agreed to do a ‘part’ 22mm pipe upgrade just so it reduces the pressure on the boiler and pump…

So the ground floor and first floor (not the loft) will get 22mm pipes upgrade, not all the way but at least halfway di water can be fed a little more efficiently….

 

[Barter78]

Work will start soon - any further feedback?

 

[johnny2007]

I have a very similar setup in my house over 3 floors.
Previous system was all 15mm and loft radiators never got very hot despite balancing the system.
When I refurbished the lot, I run 22mm pipe to loft and centre manifold for first floor.
Downstairs radiators were left to be fed by 15mm.
Now all radiators heat up nicely and balancing was very easy and never adjusted since.
Go for the 22mm backbone.

 

[Barter78]

I have a very similar setup in my house over 3 floors.
Previous system was all 15mm and loft radiators never got very hot despite balancing the system.
When I refurbished the lot, I run 22mm pipe to loft and centre manifold for first floor.
Downstairs radiators were left to be fed by 15mm.
Now all radiators heat up nicely and balancing was very easy and never adjusted since.
Go for the 22mm backbone.

The loft is very difficult to upgrade but will be having 22mm pipes through part way on the first floor and will be extending the downstairs pipes as well….

I’ve got 4 vertical and 3 horizontal designer column rads with two towel rads over 3 three floors…

What was your setup in terms of rads and boiler before and after please?

 

[Madrab]

As suggested - All that's needed is 22mm to a centralised location, which seems to be what's going to be done - the key is then running 15mm out from that location to the rads. Especially if the plans are to use larger vertical rads - 10mm pipe will always be slow to supply larger rads and given the fact that these new designer rads are really bad at warming up properly when the flow rate isn't sufficient, then the rads further out on the system may struggle.

Giving an example - my system used to use 10mm feeds and one rad in particular (600x1400 K2) would never warm up properly no matter how specifically the system was balanced - this was primarily down to the fact that the 10mm feeds couldn't deliver enough flow to supply the rads output when the rest of the system was calling.

 

[johnny2007]

The loft is very difficult to upgrade but will be having 22mm pipes through part way on the first floor and will be extending the downstairs pipes as well….

I’ve got 4 vertical and 3 horizontal designer column rads with two towel rads over 3 three floors…

What was your setup in terms of rads and boiler before and after please?

Before I had 2 standard rads in loft, 2 standard rads + 1 towel rail 1st floor, 3 standard rads + 1 towel rail and small rads at entrance hall on ground floor .

Now I have all designer rads: 2 horizontal in loft, 2 vertical + towel rail 1st floor, 2 vertical + 1 horizontal + 1 towel rail + 1 small standard rad on ground floor.

All working perfectly (maybe a bit too well if you ask me, but my wife feels always cold).
Boiler is a compact bosch 32kw.

 

[Barter78]

Before I had 2 standard rads in loft, 2 standard rads + 1 towel rail 1st floor, 3 standard rads + 1 towel rail and small rads at entrance hall on ground floor .

Now I have all designer rads: 2 horizontal in loft, 2 vertical + towel rail 1st floor, 2 vertical + 1 horizontal + 1 towel rail + 1 small standard rad on ground floor.

All working perfectly (maybe a bit too well if you ask me, but my wife feels always cold).
Boiler is a compact bosch 32kw.

That’s very similar to me to be honest…

Hopefully the part upgrade to 22mm will do the trick with a 30 kw boiler…

Thanks again

 

[Madrab]

with a 30 kw boiler…

Don't need to worry about the boiler output really, with the system that will be in place then an 18Kw HO/SYS boiler would do the job quite happily. The key to any system working properly is down to adequate flow and circulation at a suitable velocity at every end point, that's when a 22mm backbone with 15mm feeds is ideal.

 

[Barter78]

Don't need to worry about the boiler output really, with the system that will be in place then an 18Kw HO/SYS boiler would do the job quite happily. The key to any system working properly is down to adequate flow and circulation at a suitable velocity at every end point, that's when a 22mm backbone with 15mm feeds is ideal.

Gotcha!

Might be a silly question but how long can the feeds be from the 22mm pipe to the radiator?

 

[martygturner]

FYI we have a 4m run of 22mm then manifolds down to 10mm all our rads a scorching and they are all flat panel 6ft jobs without any balancing, all are wide open on a worcester 1000 30kw....

 

[Barter78]

FYI we have a 4m run of 22mm then manifolds down to 10mm all our rads a scorching and they are all flat panel 6ft jobs without any balancing, all are wide open on a worcester 1000 30kw....

What the….

Fair play - that’s contrary to what has generally been discussed - but I’m glad it works for you and I guess gives me a little hope….(although I’m still updating some pipes to 22mm)

 

[Madrab]

There is nothing wrong with having 10mm pipework from 22mm manifolds - especially where all the runs are 10mm. If all the runs are like that and similar lengths then the system can self balance as all the resistances/flows etc are similar. The problem comes when the runs are uneven, over extended or old and furred up or a mix of different sizes on a large system. That's when the system becomes unbalanced (different resistances to flow etc) and needs fine tuning, which can be difficult for a non specialist.

10mm pipework is fine when it's squeaky clean and kept that way, not so much when it's old and all furred up.

I'm at a job just now in a bungalow where the boiler is in the converted loft, 2-3m of 22mm out from the back of the boiler then 10mm plastic runs branched off the 22mm and out to the rads everywhere, it's like spaghetti junction. All the runs are massively different in length from 3m to 25m with some on the same upper level the rest on drops to the ground floor and they now have the problem where 5 (out of 12) of the old round top rads have stopped working. Every rad that is not working has no flow from either the flow or return (2 both) to the rads. Everything is behind the walls etc so no access without ripping stuff out, it's going to be a nightmare to sort out. If it had been 15mm runs then it would probably have been much harder for it to block up and it would be much easier to clean it out. As it's 10mm it won't be and it's going to be a long job.

 

[Barter78]

Interesting - very interesting