Combi-boiler gas connection

meerkit · 28 Feb 2007

Hi

We are currently getting our boiler replaced - the previous system had a large gas feed pipe reduced and then fed to the boiler. Possibly 22mm down to 15 mm.

On the new replacement system requires a 22mm feed - i just happened to notice in passing. So the plumber has put a second reducer onto the pipe so now we have gas main comes into house - reduces to 15 mm under the floor boards- runs for 2-3 metres then enlarges to 22mm again about 1m before entering the boiler.

Is this right? Surely this is the epitome of a bottleneck? Is this acceptable?

Thanks for any advice anyone can offer!

Agile · 28 Feb 2007

All modern boilers need a 22 mm gas pipe and possibly larged depending on the distance and route to the meter.

The pressure loss must not exceed 1 mB between the meter and the gas valve on the boiler.

If your installer is CORGI registered then if the installation does not meet this standard, if you complain to CORGI they will force him to upsize the pipe at his cost!

If he is not CORGI then I think the expression is that you will "whistle in the wind"! That means CORGI registered to work for YOU and not just that he is employed by British Gas because he is not registered if moonlighting.

Tony

gas4you · 28 Feb 2007

If a 28/30Kw combi then I never run more than 12/15m of 22mm copper (equivalent length), more than that it should go to 28mm and reduce to 22mm for the last 12m.

He definitely should have had the boards up and replaced the 15mm at least. If you have any other appliances coming off this gas supply matters will be even worse.

Did you see him even test pressures either end.

One way or the other get him back to do a correct job. if he is not CORGI report him.

Tony, when will the public ever be totally safe and not ripped off

meerkit · 28 Feb 2007

Hi There

Thanks for help - plumber is currently working - due to finish this evening. He is corgi registered and it is a 28kw/hr boiler.

Gas supplies our oven/hob also.

Thanks

namsag · 28 Feb 2007

Then why not mention it to him just now

gas4you · 28 Feb 2007

Make sure he actually calculates gas flow & pipe size need rather than just change all to 22mm

corgiman · 28 Feb 2007

gas4you said:
Make sure he actually calculates gas flow & pipe size need rather than just change all to 22mm

unless like WB the manufacturers INSIST on 22m minimum to boiler then that is how is has to be, or no warrantee

OP the CORGI chap in your house is wrong if he reduces it to 15mm the back up to 22mm he may as well lay it in 15 all the way

have a word

gas4you · 1 Mar 2007

corgiman said:
unless like WB the manufacturers INSIST on 22m minimum to boiler then that is how is has to be, or no warrantee

I agree with you corgiman but I was really meaning that it should be calculated any way and if necessary go to 28mm. I didn't make myself clear.

meerkit · 2 Mar 2007

Job finished and lifted hatches to see he didnt change pipe despite me pointing it out.

Also he has used compression fittings on some of the central heating pipes - is this adequate or should these be soldered?

Agile · 2 Mar 2007

Has he completed the Benchmark Certificate and notified CORGI ?

If you lived close to me then I would come free and measure the gas pressure loss on the supply for you. But thats not something you can do yourself.

And powerflushing and putting inhibitor?

Compression fittings are fine except on gas in inaccessable places. Unless it was in a difficult to solder place that would be unusual though as they are more expensive.

Tony

pannierstan · 2 Mar 2007

A little off subject but why do vaillant still inssist on putting a 15mm isolation on the gas inlet even on the 35kw Ecomax!!
It means you have to put a No3 in then a street elbow to get the pipe down the wall in a standoff clip.

Very annoying when Worcester provide a 22mm compression connection.

Stan

namsag · 2 Mar 2007

Yep still fifteen mm

gas4you · 2 Mar 2007

pannierstan said:
A little off subject but why do vaillant still inssist on putting a 15mm isolation on the gas inlet even on the 35kw Ecomax!!
Stan

Ecomax are now obsolete and only those left on shelf available for purchase. New Ecotec Plus 837 or 637 has at last got a 22mm gas connection

gas4you · 2 Mar 2007

meerkit, you still have not got a proper gas installation at your property. Insist that he comes back and corrects it

chaps · 2 Mar 2007

a gas main/pipe shouldn't be reduced and then up'ed again and on the subject of vaillants the ecotec pro 28 currently has 15mm gas connection!!!

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Combi-boiler gas connection

namsag

namsag

Similar threads