DIY Doctor UK DIY Forums

Hi Everyone,

I am in the process of getting a new boiler fitted and the installation guy says that my 15mm gas pipe is not up to the job and I need to have new 22mm gas pipe fitted.

I understand that the 22mm will provide more gas making the boiler run to full capacity. and the fact that most new boilers require this. I have a few issues with this:

- would I need to have all gas pipe work changed from 15mm to 22mm?
as the gas cooker also has a 15mm gas pipe, and even though he is a registered with CORGI is this leagal to change the pipe work, and is it safe to have a gas pipe running outside the house?

any suggestions??

new condensing boilers require a larger flow of gas to work at all, basically if they cannot pull in the correct volume of gas they will not burn efficiently, correctly, or even not light at all, and depending on the length of pipe run sometimes even 22mm is not sufficient.

if the rest of the pipework is correctly sized the 15mm to the cooker should be sufficient even when the boiler is running full tilt, but obviously you will have to trust your installer on this - no definative answers on this one unfortunately.

also although your engineer is corgi registered you should also check that they have the correct qualifications for the type of work they are being employed for:
you can ask to see their corgi card for verification or phone corgi

cheers