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Gas Works

Fitting new boiler, only have a 15mm gas pipe

Anonymous user 09/03/2024 - 3.16 PM

Hi everyone Hoping someone can kindly advise me on this. I live in a top floor apartment, counting the basement flat, I'm on the 4th floor. I have an old boiler that generally works ok, the heating is fine, the water gets hot, but never really hot, but it's started to leak and the pump also went recently and the gas engineer who repaired it said it's time to think about a new one. However he said I only have a 15mm gas pipe supply to my current boiler which makes it tricky as I need a 22mm (I think he said). The problem is with being the top floor flat, to replace the pipe, I would have to go through the flats beneath me as the gas meter is actually at ground level in a meter cupboard outside the property. The engineer who came said that the supply from the gas meter on the ground floor is actually 22mm which is of some help. My question is are there any boilers that still work off a 15 mm supply and if so are they legal to fit? The engineer said there are some boilers that still do and looking on line, I can see Vaillant may still make boilers on a 15mm supply? I'd be very grateful if someone could advise whether: A) It's ok still to use a 15mm supply B) There are definitely new boilers out that will fit on a 15mm pipe/supply Thanks in anticipation.

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3 Answers

Hatty's Heating Co.

Rating: 5 out of 5

Bexhill On Sea

Hi Colin, It is not so much about whether a boiler will fit onto the 15mm supply. The issue is that a pipe that is 15mm will supply less gas and the new boiler could potentially not have enough gas to run correctly which would make it unsafe. If it possible to calculate how much 15mm & 22mm pipe there is, work out the amount of fittings and the type of fittings they are (eg elbows, tees) it would then be possible to do a pipe sizing calculation to ensure you have the correct amount of gas for the KW of boiler that your engineer intends to fit (if different to the one you currently have) If you intend to replace your old one with a new one that is the same KW, then there are checks that can be done on your current one to ensure it has sufficient gas even if some of the supply is in 15mm. Your gas engineer should be able to carry out these checks and advise you further. There are so many variables here that it is not possible to give you a definitive answer without actually being able to see the job and carry out these checks. I hope this helps Kind regards Hatty

Answered23 October 2020

jt property services

Rating: 5 out of 5

Newcastle Upon Tyne

It's all about the manufacturers min working gas pressure at full rate with all other gas appliances on like cooker, hob etc. If when tested with all appliances on and the boiler working pressure does not meet the min manufacturer's guidelines you'll have to upsize the gas pipe until it reaches min working pressure with all other gas appliances on. If min working pressure is not met, the boiler will not burn correctly and is dangerous. Get the gas pipe upsized first is my advice

Answered23 October 2020

Martin Sankey

Rating: 4.9 out of 5

Northampton

Pipe sizing calculations need to be done this will tell the engineer how much of what size pipe is needed.

Answered18 November 2020