I've been out to a leak today, the leak had ruined the ceiling and they'd pulled the ceiling down to expose the leak and asked me to fettle the leak, so i did, it was on the heating circs a compression tee so i took it out put a soldered tee in filled up tested and all done in 1 hour, so i noticed the gas pipe was in lead up to 10 feet from the baxi 105 combi, whoever had fitted it ( 5 years ago) according to the owner, had tee'd into a gas 1/2" pipe, the pipe came off the meter in 1/2" lead then there's a nasty kink where it goes behind the plaster then travels up the wall then under the floor boards for about 30 feet where the installer cut the lead pipe sweated in 15mm copper, increased that to 22mm and put 10 feet of 22mm copper to the boiler, According to gas regs and pipe calcs this boiler can't work, BUT IT DOES, the hot water is steaming hot, so out of curiouity I measured the pressure with my manometer and it is getting enough gas, must be enough stored in the 10 feet of 22mm pipe to work the boiler, So my conclusion is, ALL those fancy figures they teach you for pipe sizes are pure tosh, they've reinvented the' bumble bee can't fly' ploy, to extract money from you, http://www.straightdope.com/columns/read/1076/is-it-aerodynamically-impossible-for-bumblebees-to-fly
So there was me, carefully measuring up the distance betwixt meter and boiler, working out the number of bends and how sharp they'd be, adding the draw of the kitchen hob wot would have to come off the same pipe, calculated that 22mm would be well fine for it all, used tool-bent sweeping bends instead of the sharp elbow fittings so's as to reduce friction further, and still the f'n hob flame wobbles every time the boiler kicks in...
Ah you see those old fitters knew what they were doing it must be that greasy surface on the lead reducing the friction As a lot of old lead was compo is it still actually legal to use/connect to I wonder?
yea its legal to connect to as long as its passes the tightness test, there are miles of lead gas pipe in houses yet, but they tell us that a combi MUST have 22mm right back to the meter,
"I measured the pressure with my manometer and it is getting enough gas" If the pipe runs are too long, theoretically it cannot work (re 1mb pressure drop etc). But if the gas rate is ok at the boiler then the only way it can possibly work is if the regulator at the meter is shot. If its bashing out 30mb or something the the boiler will get enough gas to work fine. Problem will come when someone replaces the regulator. Did you measure the pressures at the meter Tom? (Don't answer that!)
no I did't GIF, but if the regulator's knackt like yo're thinking it would have blew my manometer water out, my theory is- the 22mm lenght of copper is holding enough to keep the boiler working while the 1/2" lead is topping it up enough to keep the pressure up, If i'd have though about it better, I'd have gas rated from the meter, but it was just a curiosity thing, i was only there to fix a leak, the owner had no probs with the boiler at all, and i was't about to open a can of worms, 'last man in' or not.
All fittings/pipe work must be to bs6891 GSIUR this is not to current standard, remove & rectify with owners permission only
What is kW of boiler, this is hw rating, run hot tap with gauge on meter, working pressure at meter must be 21mbar +/- 2, then do working pressure at boiler, no more than 1mbar diff, if less do gas rate, 2 min burn, reading if metric g4 or new u6, reading x 30 x 10.72 divide by 1.11 for net, if combi do this on hw mode or heat only boiler needs to be cold for modulation reasons
G&W is correct Lead is now no longer to current standards, all lead straps on meters should be removed and replaced in copper. So Tom you should have issued a warning notice to advise you customer of the current standards as you were the last one to look at the system you take responsibility for it.
Dave, you should know me by now, i don't go by the book, I went in there to fix a leak (non gas related) as a wet plumber, all these labels and stickers are for the 'play it by the book to make money' monsters who justify it by quoting regs and promoting safety, I know you guys pay a lot to suits who issue you with badges for your polo shirts and vans ( I've done it myself) till I woke up and smelled the muck they're shovelling, the boilers running and running well, and brings to mind an old saying the proof of the pie is in the heating,
the problem wont be with the boiler, it will be with any appliances fitted that do not have a ffd/fsd. If they are lucky the flame on the cooker under the slow cook stew wont go out when they are upstairs running a bath, and they wont come back down stairs after said bath and turn the kitchen light on. its all if's and but's, if only they had not switched the light on, but why didnt they fit the boiler properly.
There are no ifs or buts, the supply pipe work must prove satisfactory, if supply pipe work does not provide the gas rate required it is "at risk" & the last person to "work" on the installation is where the finger points