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spinola · Joined: 16 Mar 2008 Posts: 2 Location: warrington

Help need advice!

I have received two quotes to replace and convert my regular boiler to a combi looking at the worcester 28i. Both prices quoted are around the £2000 mark. My problem is the second plumber who came said it looks like the pipes are only 15mm and I need 22mm and this would mean taking floorboards up possibly in the bedrooms as it has to be run from the gas meter (which is on the other side of the house to the boiler!).

My question is can I have a combi on 15mm pipes and if not are there any high effiecency boilers that run on 15mm pipes rather than disrupting all the other rooms in the house? If so, can you please recommend a regular boiler to me. The house is 3 bedrooms with a 1 bathroom and downstairs toilet.

the first plumber didn't even mention 22mm pipe or look tried to look for the at the pipes...

Any advice would be greatly appreciated - not sure what to do or who to believe! Thank you

thescruff · Moderator Joined: 03 May 2003 Posts: 4348 Location: Bath

Many installers will forget the gas pipe until they get the job then try to squeeze another £4-5 hundred quid out of you.

Powerflushing is another trick they use, so make sure it is included.

The gas pipe is sized according to the output of all the appliance, and is a critical part of the job.

Its is unlikely from what you say that 15mm would be large enough even for an system boiler, 22mm and more than likely 28mm pipe is required.

If you can post all the details I could give you a better idea, I would need the length of the main run, to the boiler, plus the number of bends ish, and the length to each appliance and they're relation to where they tee off from the main run

straker1966 · Joined: 06 Jan 2008 Posts: 164 Location: cambridge

i always run 22mm from the meter to the combi, youll only get away with 15mm if the runs is short, say less than 10 feet with few elbows on the way and thats not taking account of cookers fires etc

if the joists run the right way he can run the pipe in there or have you thought about an external run at low level. the fella who didnt mention the 22mm was either ignorant of the fact or was hoping to sting you for extras!
# go with matey who spotted it straight away- hes on the ball...

spinola · Joined: 16 Mar 2008 Posts: 2 Location: warrington

Thanks for the quick replies, it's too technical for me! I'm just worried about the disruption to the bedrooms. The second plumber sort of implied I wouldn't need to change the pipes if I stuck with a regular boiler? Is this not the case then? If I understand both the replies correctly are you saying i need to change the pipes to 22mm whichever I get whether a regular or combi? Why is nothing ever straight forward!!!

Thanks again for your replies.

thescruff · Moderator Joined: 03 May 2003 Posts: 4348 Location: Bath

Lets just say you don't want to get ripped off, and you want to get it right first time without a bucket load of extras.

A rough measure from the meter to the boiler and estimate the number of bends and we can tell within reason.