Thursday, 21 March 2013

The Tyranny of Gas (2)

As I write, the temperature's dropping and the heating's dead. It's really all my fault. My 12 year old range cooker was feeling it's age but still soldiering on, until an oven element went. A new one was £26 and I could have fitted it by removing the oven door and removing a panel. Instead I stupidly opted to replace it with a new cooker. Oh, regrets. You see, not wanting to risk the validity of insurance policies or anything else I called in a Gas Safe bod to make the mechanical gas connection - a simple 1/2" BSP fitting - and you can guess the rest. At the testing stage, he found a minor drop in pressure at the boiler (within acceptable limits), started poking about with the boiler and found something else - an incorrectly routed pressure relief valve. Formal caution issued for boiler. Then re-testing pressure drop, he found a 1/2 millibar pressure drop on the pipework from the meter. You're allowed a 4 millibar drop with appliances connected - but zero with appliances capped. Another caution, meter capped off. So I now have to put my hands in my pocket for a horrid new condensing boiler and a replacement supply pipe. 

Words cannot describe my frustration. So, reader, if anything goes wrong with your gas cooker rebuild it in-situ, every single part if necessary, except the one single gas connection that must be preserved intact at all costs to keep the installation valid. The entire gas related industry is just one huge mutually beneficial con, a scam that even I have fallen victim to.

13 comments:

Anonymous said...

Gas Safe = Rent seeking Guild.

BTW: pressure drop implies flow. If the appliances are capped off there is no flow (unless you have a leak). 1/2 milibar is 5mm H2O and about 2.5% of the 21mBar supply pressure.

I suspect either measurement error or a deliberate rip-off.

Fausty said...

Are those "acceptable limits" reasonable safety limits, or do they derive from regulations?

If the latter, then I'd wager that the government is forcing people to purchase unnecessary items to benefit its cronies / donors in the industry. Mafia-like.

The same is true of insurances. Americans are just finding out about the iniquitous mandatory purchases with Obamacare.

Anonymous said...

Pressure drop is caused by having an insufficient diameter supply pipe against the devices that use gas. Most of the older (say 25 year+ age) supply pipes are too small in diameter. But hey! The good news is that it's not your problem. I had mine replaced by Transco or the Grid, or whatever they call them selves these days and it was all done for free.

Coney Island

strawbrick said...

We have had a somewhat similar experience. Late on a Saturday afternoon - smell of gas in the kitchen, identified as small leak from one of the gas taps. Turned off gas tap and called BG. Gas man confirmed source of leak as the hob gas tap. However he did not have the spare part needed and so he "had" to shut down the gas supply at the meter "in case we turned the hob back on ...". So, no gas until mid-day Monday and no heat! But them's the rules, and imagine what would have happened to him if we had turned the hob back on and it had gone bang!!

Weekend Yachtsman said...

@anon 1825: R is talking about a pressure drop with no flow, so pipe diameter doesn't come into it. It really was a leak, albeit a vanishingly small one.

If there's a pressure loss with appliances capped off, it has to be the pipework. So why not find and fix it? Have these people never heard of a wash-bottle with dilute Fairy Liquid in it?

Well they have, of course, and it would be easy to fix it, but then he wouldn't get his commission on the new over-complicated over-electronic'ed short-life boiler that you'll be replacing again in about five years when its control systems fail and its "Oooh, (sharp intake of breath) you can't get the parts for these old things any more..." etc etc.

The whole thing is an unutterably disgraceful producer-led scam.

Not for the first time, I thank my lucky stars that there's no mains gas where I live. My oil boiler is fifteen years old and probably good for another twenty at least.

And Agas last for ever, of course.

My commiserations, Mr. R.

G. Tingey said...

ONLY JUST NOTICED HAVE WE?

Just as bad is the "Electricity safety" scam.

I have an MSc in Engineering - gu because I don't have the appropriate sub-"O"level so-called "qualification" in house electrics, I'm not allowed to do my own wiring - or MUST have it checked by a "qualified" moron.

VERY fortunateky, I re-wired the whole house just before these loopy regs came in - not because I saw it coming, but because the original wiring (from about 1908) was getting a bit dodgy ....

Weekend Yachtsman said...

Greg, how would they know?

formertory said...

@WY - "they" wouldn't know, of course. But if your house burns down because of a wiring problem and there's an evidently new installation, you'll be asked for the electrician's certificate. No cert, no insurance.

Same if you sell the house, except then no cert means the transaction will likely come to a halt while you get an electrician to test and certify the installation on "let's sting the smart-arse" hourly rates.

Raedwald said...

Update: New boiler and dedicated 22mm gas feed in. He left the old 15mm feed exactly as it was for the cooker - no detectable leak at all on it. Spivs.

The only consolation was being in the 'trade' got me £700 off the boiler installed price and I only paid £8 a metre for the new 22mm.

Joe Public said...

Hi Raedwald.

It's good to learn your major issue has been solved.

"Then re-testing pressure drop, he found a 1/2 millibar pressure drop on the pipework from the meter. You're allowed a 4 millibar drop with appliances connected - but zero with appliances capped. Another caution, meter capped off."

There are two issues here. The first is the dynamic pressure drop allowed when an appliance is functioning. As gas flows through the pipe, it meets resistance, so appliances are designed to work at a lower pressure than is at the outlet of the meter.

However, if the appliance is turned off and the slug of gas left in the pipework then loses pressure, you have a leak. That leaking outlet pipework is yours & your responsibility.

The gas engineer had no alternative but to make the installation safe, by turning it off. For your, your family's & neighbours sake. Why? Because this could have been the result:-

https://www.youtube.com/watch?v=FcP5XH7EieU

Also, remember Ronan Point, :-

http://en.wikipedia.org/wiki/Ronan_Point


Some of the Armchair Diagnostics leave a little to be desired. Particularly Anon, 21 March 2013 18:25.

"....Most of the older (say 25 year+ age) supply pipes are too small in diameter. " They were sized for the demand expected from them. Age is irrelevant. If extra appliances were added since the original pipe was sized, then that's a different matter.


"The good news is that it's not your problem." If the fault is in the pipework downstream of the gas meter, then it is entirely the responsibility of the owner.

"I had mine replaced by Transco or the Grid, or whatever they call them selves these days and it was all done for free." Transco or the Grid are responsible for the pipework upstream of the meter.

As formertory correctly responds to WY's posting, everything's fine until there's a problem. Meddling with that 'leccy stuff is relatively innocuous. Usually it's the meddler who gets the shock.

Meddle with gas and get it wrong, and it can blow your entire neighbourhood.

Raedwald said...

Joe Public - the fact is there *wasn't* a 0.5 millibar pressure drop at all; when the new fitter physically cut the supply pipe to the old boiler and capped it off with a proper stop-end the pressure drop was zero. So the first fitter, who relied on closing the old boiler's gas shut-off cock, had clearly made a mistake. The fault was with the shut-off cock not the pipe run.

OK, same result - a caution - but a repaired / renewed shut-off cock is a damn sight different to a new boiler.

The point is these guy have a cavalier attitude that brooks no contradiction - maybe the first guy took a dislike to me, maybe he's just the type that enjoys screwing customers - and he was wrong anyway under the regs to 'caution' the installation for a 0.5 drop; the regs state this only applies IF the customer smells gas, which I stated most emphatically I had never done.

The answer as usual is to learn the regs in full yourself.

Joe Public said...

Ah. My previous reply was based around the presumption that there was a leaking pipe.

Weekend Yachtsman said...

"Meddle with gas and get it wrong, and it can blow your entire neighbourhood."

Exactly.

When did you ever hear of a house being demolished because of an oil leak?

I say again, I am so glad I don't have any bloody gas.