Which new system boilers take 15mm pipe?

[Yad]

Hi all,
My 3-bed terrace in York has had a Glo-worm 85-100 system boiler, but after 20 years the water matrix has just rusted through. This boiler may not have been hyper-efficient, but it has served our heating needs perfectly.

Trying to get quotes for a straight replacement - or a condensing equivalent - but some chaps have told me vaguely that the 15mm gas supply is inadequate and would need upgrading to 22mm. If this is necessary, I'd like to be confident why. Plus the pipe is in a solid floor and I'd rather avoid running another along my wall (from meter at opposite end of house).

Could you name me any new system boilers that accept gas on a 15mm pipe? If there's a choice, I'm looking at maybe £1200-£1500 for a boiler, fitted, and system flush. Boiler can bolt to wall / stand on floor; no access problem; new flue (straight) would need bricking into old-style hole.
Cheers!

 

[ArtfulBodger]

Hi all,
My 3-bed terrace in York has had a Glo-worm 85-100 system boiler, but after 20 years the water matrix has just rusted through. This boiler may not have been hyper-efficient, but it has served our heating needs perfectly.

Trying to get quotes for a straight replacement - or a condensing equivalent - but some chaps have told me vaguely that the 15mm gas supply is inadequate and would need upgrading to 22mm. If this is necessary, I'd like to be confident why. Plus the pipe is in a solid floor and I'd rather avoid running another along my wall (from meter at opposite end of house).

Could you name me any new system boilers that accept gas on a 15mm pipe? If there's a choice, I'm looking at maybe £1200-£1500 for a boiler, fitted, and system flush. Boiler can bolt to wall / stand on floor; no access problem; new flue (straight) would need bricking into old-style hole.
Cheers!

The basic answer to your question is ...... all of them. I am afraid though you are asking the wrong question.

You should be saying something like this ....

I intend to fix an xxKW system/combi boiler in my house approximately xx yards/meters away from the gas meter. The pipe run is straight/crooked with x elbows and y tees. The gas pipe at the moment is currently in copper/steel starting at x size and finishing in y.

Then someone can answer you. I'm not being picky by the way - this is how it is.

 

[Yad]

ArtfulBodger, I see your point - but boiler is c.15 yards from the meter with all pipework under a concrete floor. I can see 22mm copper from meter to floor and 15mm copper from floor to boiler; but in-between I can only guess diameter/route (and assume 1 tee for spur to gas fire). So - best I can do is work from the observation that my existing boiler has worked satisfactorily under these conditions. I'll try to get KW spec, then question would instead be - what modern system boiler is a technical equivalent to mine? Ta.

 

[ArtfulBodger]

Glow-worm 85-100 is 29.3KW. All sounds OK to me. Take a look at www.sedbuk.com - there's more boilers than you can shake a gas pipe at there

 

[Bahco]

Whatever boiler you choose will have to comply with new regs regarding pipe sizing
My Corgi friends inform me that all new boiler installations need 15 mm pipe upgrading to 22mm.
You will have to dig a bit deeper into your pockets I'm afraid

 

[kevplumb]

according to ideal when fitting the isar condensing combi you can have 15mm pipework up to 20m i assume this is calculated lengh they dont say
so i would think the icos system boiler will be similar

 

[ArtfulBodger]

according to ideal when fitting the isar condensing combi you can have 15mm pipework up to 20m i assume this is calculated lengh they dont say
so i would think the icos system boiler will be similar

20m at 15mm? that sounds a bit odd, according to my figures that length of pipe can pass 0.95 cubic metres an hour, corresponding to about 10Kw - that's a bit of a weedy combi isn't it? mind you, it'll be cheap to run!

 

[kevplumb]

thought it sounded a bit light myself so i read thro it twice

installed one with 6 m of 15 worked fine you can read the instructions on ideal website

 

[ChrisR]

On idealboilers.com? I can't see any instructions there.

Looked my paper one which doesn't say anyting about the pipe length. But for an equivalent length of 20m and one of THOSE boilers I wouldn't dream of using less than 28mm. Anything less is asking for trouble - any ignition related problems, with anything less than 20mbar input, and Ideal will walk away.

I know 22mm should carry enough with just less than 1mbar drop in the pipe, but I always measure a much bigger pipework drop that the book says, whether mine or other people's.

 

[kevplumb]

try this
http://www.idealboilers.com/high_combi_page1.asp

 

[ChrisR]

That's odd, from the Home Page there are no links to that page on my screen! How did you find it?

The silly bit:
"Pipework from the meter to the boiler
MUST be of an adequate size, i.e. no longer than 20m and not
less than 15mm O.D."

Is plainly rubbish if they're trying to say you can use 15mm up to 20m - but it doesn't quite say that. But I don't get the length limitation - you can go as long as you like as far as I know if the pipe's big enough.

 

[kevplumb]

i hear what you are saying chris and i agree ive' installed one on 6m and it was fine but to me thats the limit

there is something in there about a 1:1 gas valve mabye it makes a difference

sorry cant remember how i found that page clicked about 5 links

but like the corgi get out if its in the mi s its written in stone