Re: 22mm or 1" pipework to boiler. Help

Aug 29, 2003 6 Replies
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In article , snipped-for-privacy@hotmail.com writes



I've been given three different statements by Corgi fitters with
>regards to the length of pipework running from an old boiler to the
>mains in the flat my fiancé bought six months ago.
>Currently the run is an excessive one on 15mm pipe (over 30m all told
>with multiple 90 degree bends and a hob spurring off). As all three
>have commented, the boiler and hob should have gone bang by now. There
>are no other gas appliances.
>A: replace the run with a new shorter run of 22mm pipe from the point
>of entry to the house to the boiler. 15mm spur to hob. This gives a
>total run of 17m in the house, 4m to the mains outside, with 10x 90
>degree bends. He says anything under 30m in total, taking bends as >0.5m is acceptable.
>B: replace the lot from the mains into the house with 1" pipe most of
>the way (up to about 6m from the boiler).
>C: Move the boiler.
>What I can't get clear from them is what the safe/legal/most cost >effective option is.
>A would be the easiest option as the run from the mains to the house
>would be untouched (it steps down from 22mm to 15mm about two feet
>into the house) and this is an awkward section to re-fit. I've punched
>holes for the run of pipe already so it should be a fast job. But
>would it be safe/legal?
>B is really more than I can afford. The written quote isn't in yet,
>but verbally quoted 3 days work with one day just for replacing the
>22mm mains to the house section
>C is not an easy option. It's a basement flat so the only walls
>available to vent are front and back. It's a Listed building, so the
>front wall is no go. On the back wall I could fit a new boiler
>slightly nearer. The run would then be 13m with 6x 90 degree bends,
>plus 4m to the mains outside, and a 15mmm spur to the hob. Would this
>be possible on a 22mm run of pipe to the boiler?
>
>I don't know which of the fitters to believe, so any advice, links,
>recommendations or comments would be an enormous help.

Really good calculator here:

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Copper Tube Sizing , it's what I used for my installation. Should let you calculate the effect of your initial


15mm followed by a 22mm length.
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A

In order to work this out, the maximum ratings of both appliances are needed, as well as the meter position relative to this lot. Almost certainly, with typical appliances, one can say that 15mm tube over the distances mentioned are not enough.

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information and a worked example, so you can at least get an idea of what is involved.

The pipework should be designed so that the pressure drop between the outlet of the meter and the appliance does not exceed 1mbar at maximum flow conditions.

Option A *may* be adequate if the boiler is relatively small, but you would need to do the sums.

Same for Option B although again the calculations are required. This would likely be required for a larger or combi boiler, and I suspect the calaculations would show it to be belt and braces for a smaller boiler.

Option C seems similar to Option A.

Getting the pressures right is important both for operational and safety reasons.

From the perspective of doing any DIY work, the law requires you to be competent if you want to do your own fitting work, but does not define it. Professional fitters are required to be CORGI members.

There are a bunch of issues associated with installing a hob as well as installing a boiler that have to do with fitting arrangements, flues, ventilation and so on. The fact that the pipe sizing issue is probably wrong invites the question as to whether anything else is wrong.

There is more information in Ed Sirett's gas fitting FAQ Gas fitting FAQ

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.andy

To email, substitute .nospam with .gl

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M

Andy Hall wrote in news: snipped-for-privacy@4ax.com:

The fact that the pipe sizing issue is

Thanks so much for not saying "begs the question"

Do you think you could get hired to train BBC and other meejah folk in basic English?

mike r

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I

God help us if he did. He would be gob-smacked touching base all over the place.

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I

This "invites the question", could he do it with reverting to Little Middle Englandness?

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A

From one who is incapable of correct spelling or grammar, or even constructing something resembling a sentence, that remark is nothing short of amazing.

.andy

To email, substitute .nospam with .gl

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