Heating circuit outlet pipe diameter?

[boomcox]

Hello,

I am preparing the installation of a gas boiler (Atlantic Naema 35kw) with a wood boiler (solo innova 30 + 2000l tank with DHW). But I have a question about the diameter of the pipes: the current start is in copper 28mm ext then 1"1/4 in iron, the gas boiler has a 20/27 pipe, smaller than the current installation.

I won't have flow problems?

Thank you for your opinion.

Have a good day!

[Christophe]

No, who can do more can do less, the less pressure drop there is in a heating circuit, the better.

If the circulator of the new boiler is electronic it will adapt automatically and this will save you electricity.

If it is still an old circulator with 3 speeds (it would surprise me if the boiler is new), you will put on the smallest one.

You can look at this topic about electronic circulators I installed one a few months ago: chauffage-isolation/biral-mx12-1-bloque-remplace-par-circulateur-electronique-biral-ax-25-4-180-red-t17021.html

On the other hand, remember to insulate as much as possible the large 1 1/4 iron pipes... large pipes are good for pressure drops but it causes more heat loss.

[boomcox]

Ok, that will do it… but I have to insulate the pipes!!

Thank you for the answer,
Have a good day

[phil59]

Distrust of iron pipes ....

My mother-in-law had iron pipes on a 60s installation.

A first leak around 2011, which has been repaired.

at the end of 2012, a second leak ....

The iron pipes were beginning to be "rotten", corroded inside.

I redid his installation in PER ....

The radiators follow one by one, cast iron radiator. I changed it again last summer....

[Christophe]

An iron circuit only corrodes if there is an oxygen supply...and except in the first underfloor heating without BAO (my case), there is no oxygen supply in a heating circuit except leaks.

My plumber advised me to put hydrazyne in my circuit without BAO.

I also put an anti-leak because I had pressure drops regularly.

It worked very well!

[phil59]

I'm not talking about a small leak, but 10-20 cm2 of pipes which "detaches", as if it were exploding .... greatly exaggerating of course!

[Christophe]

It can corrode from the outside actually...

[dede2002]

Distrust of iron pipes ....

My mother-in-law had iron pipes on a 60s installation.

A first leak around 2011, which has been repaired.

at the end of 2012, a second leak ....

The iron pipes were beginning to be "rotten", corroded inside.

I redid his installation in PER ....

The radiators follow one by one, cast iron radiator. I changed it again last summer....

At home, it's all steel and cast iron, the installation dates from 1897... and nothing moves!

[Macro]

Ditto... Good at home it's only 50 years old for the cast iron part and 20 for the floor which is copper steel...

I had inserted a cast aluminum radiator that was giving me the hell (gas in the pipes) since it was removed, no more worries...