Low Gas working pressure at Boiler

[Jimster]

I have a ferroli f30 combi boiler, I have 27mb of pressure at my meter, and the same at my boiler, but the working pressure at my boiler drops to around 17mb. Sometimes my boiler has problems lighting, and it keep going out, 1 second after lighting, I'm guessing this is because of the low pressure.

I belive the problem is becuase I have around 30 meters of 22mm pipes between my meter and boiler, with lots of 90 degree bends, do you think this is the case?

If so what do I do to fix it, could I run another run of 22mm pipe paralell to the current pipe, or should I replace with 28mm.

Or am I barking up the wrong tree.
Cheers
Jim

 

[ollski]

you have a dangerous installation. For a start you need to get in touch with transco who will sort out your high pressure, you can have 19 - 23mb at the meter anything above should cause the governor to lock out. The boiler instructions will tell you what pressure the boiler should be working at though 17mb may be possible it is the 10mb drop you need to worry about, the maximum pressure drop is 1mb!!

I should guess you need 28mm pipe but get a corgi round to work it out properly

 

[ChrisR]

I think you must mean that the pressure at the meter AND boiler is 27mbar when nothing is on. This means nothing! The working pressure at the meter should be in the range oilman said. It's true that 1mbar is the corgi stipulation, but half the nation's boilers have a bigger drop than that in the pipe to them.
I don't have the figure for the BURNER bressure for the F30, but if it's less than 14.5 mbar or so then 17mbar, working, inlet pressure at the boiler, will be enough for it to work OK.

I have to say that non-corgi shouldn't be dabbling with gas supplies. Would probably have no knowledge or kit to test for leaks.

 

[ollski]

sorry I misread working pressure at the boiler for inlet pressure. The working pressure is adjustable and will change as I think you have a modulating gas valve in there.

Fully agree with chrisR's last statement though.

conditions do not change though, if your system was installed with undersized pipework get on to the installer to put it right.

 

[Slogger]

can he piggy back a 15 or 22 mm pipe running alongside his old one if he had room to do it ( just a thought as 28 mm pipe is expensive)

 

[breezer]

how does he know what the gas pressure is, isn't it an "offence" to touch gas unless qaulified? but to know the pressure would that not mean to use a "gas pressure tester" which would mean touching the gas?

 

[croydoncorgi]

Ollski is (dangerously) confusing 'working pressure' with 'burner pressure'.

Working pressure is measured upstream of any modulation the gas valve does and is the actual pressure of the gas supply into the valve when the valve is open. The pressure when the valve is closed is known as 'standing pressure'. Burner pressure is the pressure output by the gas valve to the burner and / or measured in the burner manifold.

Given your description of the piperun, the pressure drop is no surprise. Also, the meter governor is obviously set too high or defective but if it is reset to the nominal 20mB, then you really will have a problem! The working pressure will probably drop from 17 to 12 or 13 mB. OK - excess pressure at the meter is wrong - but IF the boiler is the ONLY appliance in use, I suggest you get the pipework fixed before the meter. But if you have other appliances (eg. cooker) of the same supply, then you MUST get Transco to fix the meter urgently.

If the manufacturer says the boiler needs 20mB plus / minus 1 mB - then that's what it needs. Just possibly the F30 can tolerate 17mB - but I doubt it (I have no tech lit for this model).

 

[ollski]

Yes just read my second post......what am I talking about??
Standing pressure at meter.......don't worry
working pressure at meter .....19-23 mb on existing installation 20 - 22 0n new, above or below requires transco to adjust you regulator.
Working pressure at appliance full rate 18 - 23mb as long as it is a maximum 1 mb drop in pressure from the working pressure at the meter, measured at the gas valve inlet.
Burner pressure...whatever the appliance should be set to in the manufacturers instructions, normally adjustable by either potentiometers on the pcb or the gas valve governor.

Wheather the appliance is ncs to at risk if it is dropping over 1mb depends on if it is affecting the operation or not, with the boiler probably not, but with other appliances it probably will as croydon said.

 

[corgiman]

This is NOT a subject for a DIY forum

THIS IS CORGI LEAVE IT ALONE!!!!!!!

And at the risk of being ridiculed would everyone STOP advising this poster as it could lead to disastrous consequences.

Please Jimster unless you have undergone thorough training and have the relevant qualifications and registrations leave it alone and get a professional in to deal with this.

 

[Registered Gas Man]

27mb standing pressure is np it means nothing!!

17mb working pressure on a 30kw appliance (F30) is dangerous!!

If so what do I do to fix it, could I run another run of 22mm pipe paralell to the current pipe, or should I replace with 28mm.

This is ludicrous!!

can he piggy back a 15 or 22 mm pipe running alongside his old one if he had room to do it ( just a thought as 28 mm pipe is expensive)

I hope you are joking!! Death or a few quid??

30 meters of 22mm pipes between my meter and boiler, with lots of 90 degree bends, do you think this is the case?

This just says it all!! 30 METRES OMG!! There lies the problem!!

Oh and also the fact you have ignored probably page 1 of the F30 instruction manual, where it mentions competent person!!

I could solve the lighting problem by commisioning the thing, thats after id reinstalled it!!

 

[Slogger]

seems the corgi thing is overated i mean what is competent ? dont tell me u pay corgi therefore u r hmm they are as i said before toothless in these matters no wonder people do the diy gas themselves If u go down to B+Q on a bank holiday weekend ( or any weekend) and see how many GAS appliances are being sold to THE PUBLIC i was behind a guy who bought 2 gas fires BQ special offers £50 a piece in the sale coal effect jobs i said to him it will cost more to fit them and he laughed at me saying why pay someone when B+Q sell the fitting kits too >>> do the corgi lads lobby errr corgi about this ?? i bet not and if not why not come on lets stop joe publice getting his hands on WIDOWMAKERS they banned guns and these things are more dangerous or am i WRONG how hard would it be to make it law that u have to show your badge to buy anything to do with a GAS appliance ?

 

[krispy]

About as hard as it was to make the laws for taxing and insuring your motor vehicle and we all know every one in the UK sticks to that one

 

[ChrisR]

"seems the corgi thing is overated i mean what is competent ? "

Well if you were trained you'd know. Not being trained, you for example won't be able to test for leaks. It isn't remotely difficult but you have zero chance of doing it effectively by guessing the method. There are too many bits you have to know, to learn from a website. Even soldering the copper is not the same as for water pipes.

Only 50 or so people die each year from gas related incidents. 1500 die falling down stairs. So don't wait for legislation.

 

[corgiman]

HEAR HEAR ChrisR

 

[Slogger]

well i am very sorry to all you errr corgi ( gas fitters ) that paid your subs or whatever it is u pay to corgi but seems to me you where robbed
what is the point in a business made to oversee gas installations ( that is there job isnt it ) that has no law to back it up #
i say no LAW cos ( short for because) if u (short for u ) phone them up and actually tel them u r going to install your own GAS cooker and ask them if that is actually LAWFULL to do they will tell you yes it is ? then they will go on and say as long as you are competant and we all know where that leads to ( check diy disaters )
come on corgi fitters lobby your overseers ( masters ) and try to get this ILLEGAL to actually touch anything to do with GAS there isnt any room for grey areas here is there ?
or would that be takig too much cash from the likes of BQ /WICKES etc

as for the piggy backing of pipes ? why not ? 28 mm vs a run of 15 or 22 x2 surely if there was room what would be the problem if the job was done right and the correct working pressure was attained what would be the problem aside from the obvious huge holes all over

dont ridicule explain

no spell check was hurt in the making of this errr writing

no doubt one or two english teachers will hit me with my diction