Gas pressure at boiler 1/4millibars below min. What to do?

KTF

OK, Transco confirms that its 21 at the meter so its down to the internal pipework.

Bother

moneysavingplumber

If this is a new boiler installation as you have described, I'm interested to know if the installer was Corgi registered. Whenever surveying any proposed boiler change, one of the first things any competent person will do is check the size of the gas supply. On a combi installation of a 24KW boiler there will always be a requirement of 22mm pipe to within one metre equivalent-length (i.e. allowing 1m add-on length for any elbows) of the boiler. It is the commissioning engineer's responsibility to ensure that the correct standing and working gas pressure are available at the appliance. If the installer has connected to a 15mm supply then they are responsible for the problem and it should not be left up to you to investigate via Transco/Fulcrum or whatever they are called now.

It sounds as though the fitter has (foolishly in my opinion) chanced an arm on the existing supply being adequate, and is now trying to re-negotiate the terms by trying to lay the responsibility of it at your door. I presume you are referring to the installer when you say he says he won't sign it off until he has the adequate pressure.

I'm surprised that a competent person would not consider the size of the supply until commissioning. I would check their registration details at http://www.corgi-gas-safety.com/section_gas_law/about_installer_check_installer.asp and if that is all well and good I would suggest negotiating an agreement with them whereby they agree to upsize the pipework taking at least some of the responsibility for the error, although I personally think it is entirely their responsibility if they have misquoted and then tried to add it as an extra later on.

oldagetraveller

I had a Glow-Worm 18Hxi boiler fitted as a replacement three months ago. Just about the first thing all three of the CORGI installers who quoted for the job checked was the size and length of the supply pipe. In my case it was 15mm and totally inadequate for both the existing(50000Btu) and the new boiler.Two said they would carry out the work but not be able to "sign it off", the other insisted on a new supply. I went with him eventually.
When tested, after insallation, the pressure at the meter was low at 17mbar and even less at the boiler! Transco had to come and fit a new regulator/governor to the meter.
I would therefore suspect you had a "not up to scratch" installer. Did you obtain any other quotes and if so was the supply checked by them at the time?

moneysavingplumber

oldagetraveller wrote:

Just about the first thing all three of the CORGI installers who quoted for the job checked was the size and length of the supply pipe. In my case it was 15mm and totally inadequate for both the existing(50000Btu) and the new boiler.

Thankfully you believed them, alot of people have a fantasy that all plumbers are out to deliberately add more work to a job, most of us barely have time to do the work we already have and there is nothing nicer than an easy boiler change that doesn't require upgrade work, it's a chore explaining it and I am aware that I have lost jobs as a result of a competitor not quoting to uprate the pipe sizing.

catkins

You need a minimum pipe diameter of 22mm to within 1 metre of your boiler. Any competent plumber should know this and a CORGI plumber MUST know this. If he saw the pipes before starting and connected to them he should shoulder the blame and put it right.