Why size of gas pipe?

[Dotty]

Ask the manufacturer!

 

[Nostrum]

The only point I was making was that if boilers needed at least a 22mm supply, why did they have a 15mm connector!

Because for natural gas yes 22mm is standard, but LPG may only require a 15mm supply, and seeing the boiler boiler is the same for both fuels, either way someone has to use a reducer so you can't win.

There are many cases where a 22mm supply may not suffice, so you would still need a 22mm - 28mm reducer, should they bring out a boiler with a 28mm inlet as well just to save using a reducer?

Most boiler manufacturers do not state a minimum supply size, all they mention is that is should be installed in compliance with regulation and state a minimum inlet pressure.

Worcester, as far as I am aware are the only ones stupid enough to to put statements like this into the manual (amonst others for example the minimum inlet pressure on LPG must be 37mb, even though you are allowed a 2.5mb drop across pipework on LPG) which should be adhered to according to regulations) and is yet another reason why I would rather burn my own testicles with cigarette butts than sell their products.

 

[GrahamM]

The only point I was making was that if boilers needed at least a 22mm supply, why did they have a 15mm connector!

You are not getting this!
It is all about the volume of gas that pipework supplies.
If the gas meter is no more than a few meters away and no other gas appliances, more than likely a 15mm supply will suffice, so why fit a slightly more expensive and more hassle 22mm run. If further away or multiple appliances the engineer will be able to calculate the size of pipework required to supply the volume of gas required for the particular installation.
I have been to many boilers supplied by a 15mm supply that is 100% sufficient for that particular installation. I have also been to many serviced by 22mm supply, that due to the distance from the meter etc. the 22mm supply was insufficient and boiler under-gassed.

 

[peteheat]

You are not getting this!
It is all about the volume of gas that pipework supplies.
If the gas meter is no more than a few meters away and no other gas appliances, more than likely a 15mm supply will suffice, so why fit a slightly more expensive and more hassle 22mm run. If further away or multiple appliances the engineer will be able to calculate the size of pipework required to supply the volume of gas required for the particular installation.
I have been to many boilers supplied by a 15mm supply that is 100% sufficient for that particular installation. I have also been to many serviced by 22mm supply, that due to the distance from the meter etc. the 22mm supply was insufficient and boiler under-gassed.

And further away you may have to start with 28mm (1") and reduce down to as you go, for the last 2 metres 15mm may be sufficient.

To the O.P.,

It is what you are paying your heating engineer / plumber the big money for, his knowledge and skills.

 

[Koogatubac]

Guys why are you all explaining this to a guy who clearly doesnt have a clue? He needs to seek advice from a heating engineer that he gets. For all we know he could be attempting the gas installation him self with all this knowledge thats been spread all over this topic

 

[GrahamM]

Any layman with a bit of basic knowledge can fit a bit of pipework.
If he is silly enough to use his 2 brain cells to attempt this with gas then he is going to do it regardless.
The info here gives no encouragement or direct help in this, it is just discussing the size of a gas supply.

 

[Mike Jackson]

My hope is that he will leave the poor bar steward that is working for him in peace to do the job.

 

[Koogatubac]

Lol i really dont know how anybody could even risk touching stuff thats as dangerous as gas since they havnt been trained to work on.

Just for the sake of money! Even people doing their own plumbing! My grandad is a prime example. He used to do his own plumbing and he plumbed the kitchen sink up, i had a look at the waste and instead of having a fall it was perfectly level :|

 

[Bernie2]

Hmm! As said the resistance of the pipe route decides size of pipework. But there is always a tendency I suppose to say 22mm because that is the size normally used. It does no harm to oversize a gas pipe but could cause problems if it is undersized, so on balance fit a 22mm pipe.


The boiler may not require a 22mm supply so the manufacture makes it 15mm. And even 15mm would work if the boiler is not very far away from the meter. But on balance most guys probably feel using 15mm it may or may not get enough gas but usually 22mm makes sure it does. And as they do not want customers complaining they fit 22mm.

 

[stevetheplumber]

the bottom line is they fit a 15mm connector as its the cheapest they can get

 

[Howsie]

the bottom line is they fit a 15mm connector as its the cheapest they can get

Spot on. The accounts rules the roost!

 

[Nostrum]

and the internal pipework within the boiler is usually around the 15mm size

 

[snowhead]

If boilers only need a 15mm supply then surely they could uses 15mm pipe all the way back to the North Sea,:hurray:

 

[kirkgas]

The only point I was making was that if boilers needed at least a 22mm supply, why did they have a 15mm connector!

are you going to keep asking this till someone says you are right, listen to the advice you are being given, you aint gonna get much better advice than you get here, if the gas meter is right under the boiler 15mm pipe will be fine, so the boiler is capable of being connected to 15mm pipe and will work, however customers dont always like their boiler outside or under the sink so you then need an expert to design the pipe from the meter to the boiler then reduce it to make the final connection

 

[Rickster123]

are you going to keep asking this till someone says you are right, listen to the advice you are being given, you aint gonna get much better advice than you get here, if the gas meter is right under the boiler 15mm pipe will be fine, so the boiler is capable of being connected to 15mm pipe and will work, however customers dont always like their boiler outside or under the sink so you then need an expert to design the pipe from the meter to the boiler then reduce it to make the final connection

amen!

 

[Barry98]

Can't teach common sense am afraid , what every industry , trade etc someone will always want to cut corners to reduce costs. The consequences of there actions are secondary . Thank fully where I live all 3 of our neighbours ask me to do there work.

 

[mountainman]

So your garden maintenance business is picking up then Bod. Lol

 

[Barry98]

So your garden maintenance business is picking up then Bod. Lol

Had a bit of a heat wave on , so I've been cleaning windows

 

[scorps]

[ My grandad is a prime example. He used to do his own plumbing and he plumbed the kitchen sink up, i had a look at the waste and instead of having a fall it was perfectly level :|[/QUOTE]

:whatchutalkingabout
if that's all you could pull on his work he did'nt do that bad a job :smile5:

 

[Barry98]

[ My grandad is a prime example. He used to do his own plumbing and he plumbed the kitchen sink up, i had a look at the waste and instead of having a fall it was perfectly level :|

[/QUOTE]

Should of gone to specsavers

 

[kay-jay]

Can't teach common sense am afraid , what every industry , trade etc someone will always want to cut corners to reduce costs. The consequences of there actions are secondary . Thank fully where I live all 3 of our neighbours ask me to do there work.

3 neighbours??
One to the left, one to the right and the gypsies in the garden??


Or are you the gypsy in the garden

Sent from my GT-I9100 using Tapatalk 2

 

[REDSAW]

the bottom line is they fit a 15mm connector as its the cheapest they can get

why dont they do it in 8mm then?.
that way installation will be quicker with the routing of pipes

 

[CES]

why dont they do it in 8mm then?.
that way installation will be quicker with the routing of pipes

Have you seen the cost of 8mm fittings???

 

[Dotty]

why dont they do it in 8mm then?.
that way installation will be quicker with the routing of pipes

Naaaa. There would be tiger loops being installed left right and center. And we all know how much bother they give on a gas installation.

 

[stratobuddy]

Thanks for all the sensible answers lol.

BTW some years ago a qualified plumber/gas fitter put in a replacement high level toliet cistern in my Dad's house.

He then found the overflow outlet was on the wrong side, so could not go directly out of the wall like the previous pipe.

So he did some very neat pipework out of the other side of the cistern, upwards to clear the top of the tank, horizontally along the top of the tank, back down the other side then horizontally out through the original hole in the wall.

I spotted this wonderful plumbing when I was standing there one day using the facilities.

What prize shall I give for anyone who can spot what was wrong?

PS I feel it is a good job I didn't ask why he didn't do the whole gas pipe run in flexi to make the job even easier!