Gas Main Question

[revjames]

I am in the process of getting a new boiler fitted. Its a Worcester Bosch 30i, The boiler is located in a utility room at the back of the house and the meter is at the front. So a long run (20 - 25m) of 22mm copper pipe. Other appliances include a dual fuel cooker of which only the rings are gas and a gas fire which is not used and currently disconnected. Anyone able to advise based on this info if my pipe is big enough?

Thanks

 

[kerching]

I have a worcester Bosch 30 CDi

13 m run from meter to utility rm

Probably 7 right angle bends

Main also feeds 1 BFO gas fire and a disconnected smaller gas fire

Main had to be increased to 28mm

Just saying

 

[Rob_the_rich]

Without doing the calcs, it does seem like you are on the edge of the capacity of a 22mm pipe, with bends.

You can connect up the boiler and test the inlet pressure. If ok, a good test is to have the hob on with the smallest ring on low, then fire up the boiler at full rate and look at the flame of the small burner to see if it goes lazy or extinguishes.

If a larger supply is needed, you can run a parallel pipe along another route, eg around the house, connected at both ends. Not a lot of people know that.

 

[revjames]

Thanks guys, just a thought, if it failed by a small amount, would increasing the pipe to 28mm for the first half of the run be an answer? I say that becauuse the pipe is under the wooden floor and quite easy to get to for the first half of the run.

 

[NozSpark]

If you could put 28mm up to the first tee then it would help

 

[Lurch]

Or you could, you know, actually do some calcs rather than half arsing it and guessing.

Pretty sure the answers would be diffferent if you asked how big your cable to the shed should be.

 

[Rob_the_rich]

It would probably work. also replacing 22mm elbows with drawn bends helps a bit. Your Gas Safe Installer will advise I am sure.

 

[revjames]

Or you could, you know, actually do some calcs rather than half arsing it and guessing.

Pretty sure the answers would be diffferent if you asked how big your cable to the shed should be.

we would be far more sarcastic and condescending (isnt that a type of boiler?) after all plumbing is only watertight conduit......

 

[Lurch]

What has plumbing got to do with it?

 

[Sidewinder]

Just remember that DIY gas work is not notifiable under Part P, and is legal!

 

[revjames]

What has plumbing got to do with it?

dunno, youre the one pretending to be clever and going on about calcs etc, 

 

[Andy™]

Or you could, you know, actually do some calcs rather than half arsing it and guessing.

Pretty sure the answers would be diffferent if you asked how big your cable to the shed should be.

get a cable size wrong and it could melt, cause a fire, not trip breaker in time etc.

get the pipe size wrong and worst case the boiler might take slightly longer to warm the house...

 

[Lurch]

dunno, youre the one pretending to be clever and going on about calcs etc,

By this point you would be told you are an idiot and not to even think about looking at wires.

get the pipe size wrong and worst case the boiler might take slightly longer to warm the house...burner may produce excessive amounts of CO2.

 

[Richard-the-Ninth]

get the pipe size wrong and worst case the boiler might take slightly longer to warm the house...burner may produce excessive amounts of CO2.

Andy never said that, and besides, it CO, NOT CO2

CO is carbon monoxide and is lethal in tiny amounts

CO2 is what makes fizzy drinks fizzy. (It is also lethal but not as bad as CO)

 

[Lurch]

Andy never said that,

Well he did, as you can plainly see. Or are you alluding to the fact that I edited the quote, which I clearly did to correct the quote, not to hide or obfuscate any previous comments (which are still posted for anyone to plainly see).

and besides, it CO, NOT CO2

CO is carbon monoxide and is lethal in tiny amounts

CO2 is what makes fizzy drinks fizzy. (It is also lethal but not as bad as CO)

Obviously a typo. Thankyou.

 

[revjames]

Thanks for al the constructive replies guys. Boiler will be with me tomorrow, as its the same heating output - 24kw, I am hoping it will just about be OK with existing pipework. The previous boiler was 24kw and the gas safe guy who comissioned it 10 years ago said it was only just passable. 

Gas safe guy will be coming to do his "calcs" connect gas pipe and commission next week so fingers crossed.

Shame some people come on with a bolshy attitude and try and turn every thread into an argument.

 

[Rob_the_rich]

get a cable size wrong and it could melt, cause a fire, not trip breaker in time etc.

get the pipe size wrong and worst case the boiler might take slightly longer to warm the house...

I agree to a point, with room sealed boilers nowadays any CO produced should get blown outside. But incomplete combustion can cause more frequent servicing and more costly strip downs due to sooting etc.  It would not be installed to MI, resulting in voided warranties etc and if an installer left an installation with low gas pressure, what else might they have ignored (case seals?)?

Main danger I see in this scenario is hob flame extinguishing (with no flame supervision devices fitted) when there is hot water demand. When hw demand ceases hob gas supply re-instates and could case an explosion. Also, a hob is flueless, and any incomplete combustion there, due to low gas pressure, may cause CO build up in the kitchen.

And if the gas fire was re-instated......

 

[Lurch]

Shame some people come on with a bolshy attitude and try and turn every thread into an argument.

You must be new h.....

nm

And if the gas fire was re-instated......

Hopefully not by being blindly teed into the nearest thing that looks like a gas pipe.

 

[Andy™]

incomplete combustion is lack of oxygen... if there is less gas going in then there will simply be less gas to burn so less heat created.

same as a gas cooker - turn down the gas and you get less heat, not co

Hopefully not by being blindly teed into the nearest thing that looks like a gas pipe.

well i have worked with plumbers who had water coming out of the cooker & gas meter a few times...

 

[Lurch]

incomplete combustion is lack of oxygen... if there is less gas going in then there will simply be less gas to burn so less heat created.

same as a gas cooker - turn down the gas and you get less heat, not co

I did read a decent article explaining this quite some time ago which I was going to reference but I can't find it. It is more to do with the gas valve/regulator/burner characteristics than simply reduced flow rate producing a smaller flame.

well i have worked with plumbers who had water coming out of the cooker & gas meter a few times...

Also seen shower wastes teed into extract vents.