Gas pipe run
 

Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)

I need to know fairly quickly this time. Boiler power 30-40 whatnots

thank you,
NT

No
It would not be acceptable for an older boiler


wrote in message
oups.com...
Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)

I need to know fairly quickly this time. Boiler power 30-40 whatnots

thank you,
NT

On 8 Sep 2005 06:38:21 -0700, wrote:

Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)


I need to know fairly quickly this time. Boiler power 30-40 whatnots

Kilowatts? If so, then almost certainly no.



thank you,
NT

--

..andy

To email, substitute .nospam with .gl

wrote:
Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric

Doubt it. My boiler's about 18 whatnots and the manufacturers specify
22mm pipe to within about 12 or 18" of the boiler. There might be
something similarly specified in the installation manual for your
boiler. You can't calculate the pressure drop (which is usually the
criteria) without details of all the other appliances, pipe lengths,
tees, etc..

Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)

I need to know fairly quickly this time. Boiler power 30-40 whatnots

No, if you mean kW. It might be OK for kBTus (an ancient unit), but
calculations might be in order even then.

Christian.

wrote in message
oups.com...
Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)

I need to know fairly quickly this time. Boiler power 30-40 whatnots

thank you,
NT


If you have a look here http://www.cda.org.uk/megab2/build/pub124/sec3.htm
you should be able to work out just what size you'll need (note the
additions for 90 degree elbows etc.) and also how much extra capacity the
pipe will have, should you wish to add any extra appliances at a later date.

Alex

Christian McArdle wrote:
Is a 25' run of 15mm supply pipe acceptable for a new boiler? Thats gas
supply, not electric :)

I need to know fairly quickly this time. Boiler power 30-40 whatnots

No, if you mean kW. It might be OK for kBTus (an ancient unit), but
calculations might be in order even then.

Christian.


Thanks to everyone :) I am pretty ignorant on this, but assumed its
kbtus. Its probably 30 odd years old. The 15mm supply has never been a
problem in any way, but thats bureaucracy for you.

So I guess I'll have to run a 2nd pipe in parallel to lower the
resistance. I've got an old hose reel somewhere...


NT

Thanks to everyone :) I am pretty ignorant on this, but assumed its
kbtus. Its probably 30 odd years old. The 15mm supply has never been a
problem in any way, but thats bureaucracy for you.

If it has worked perfectly for 30 years, then leave it, unless it has failed
an inspection. Without doing the calcs, and assuming few elbows, the run is
probably just below spec. Perhaps someone will be kind enough to do the
calcs for you!

Christian.

Christian McArdle wrote:
Thanks to everyone :) I am pretty ignorant on this, but assumed its
kbtus. Its probably 30 odd years old. The 15mm supply has never been a
problem in any way, but thats bureaucracy for you.

If it has worked perfectly for 30 years, then leave it, unless it has failed
an inspection. Without doing the calcs, and assuming few elbows, the run is
probably just below spec. Perhaps someone will be kind enough to do the
calcs for you!

Christian.


Yep, its failed. A new run it is - wont be hard to do. Its the new
boiler I'm unhappy about.

Oh, yes there was another appliance run off that section of pipe too. I
guess I had modulation and didnt know it :)


cheers, NT

Yep, its failed. A new run it is - wont be hard to do. Its the new
boiler I'm unhappy about.

Oh, yes there was another appliance run off that section of pipe too. I
guess I had modulation and didnt know it :)

Ah. Another appliance will drop it much lower!

If the other appliance is greedy, you might even need 28mm to the split and
22mm after. There's no point in underspeccing the new run. Your next boiler
might be a 40kW monster.

Christian.

Christian McArdle wrote:

If it has worked perfectly for 30 years, then leave it, unless it has failed
an inspection. Without doing the calcs, and assuming few elbows, the run is
probably just below spec. Perhaps someone will be kind enough to do the
calcs for you!

Well if you take a m^3 of gas as 37MJ, assume the boiler is 40k BTU
(11kW ish) that gives you 11000*3600 J / hour, or about 40MJ. So that is
a gas rate of approx 1.1 m^3 / hour.

Lets call the pipe run 9m to allow for some bends etc.

According to:

http://www.cda.org.uk/megab2/build/p...0Tube%20Sizing

9m of 15mm will be good for a gas rate of up to 1.5 m^3 / hour

So you look ok right up until the bit where you mention there is another
appliance on the pipe! ;-)



--
Cheers,

John.

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