When boiler fires hob flames go down
Seri
am desperately worried that I've made an error somewhere. As is the
way, I thought I'd gone by the book, but it appears I may have over
looked something. If it was anything other than gas then I wouldn't be
'too' concerned, but...
I very recently replaced the gas hob that was in this house when we
purchased it. At the same time I removed some of the old gas piping
(had very small leaks behind the oven and was way out of spec). The old
gas pipe didn't have an isolation valve and had a very small leak.
In the new system I fitted an isolation valve, replaced the hose
connection with a soldered joint and removed about 5 straight through
connectors and elbows to replace with a nice clean straight run.
The problem now is that when the combi boiler fires for water or
heating the hob flames get smaller. On individual rings it's not really
noticeable, but on the large centre ring it's quite significant.
I've checked the isolation valves on the boiler and hob and they're
both open full, I've also checked the valve on the gas meter and that
too is fully open. There aren't any other gas appliances in this house.
Have I done something wrong? and what can I do to rectify this?
Thanks as ever for any and all advice.
Seri
Derek Doormer
fitter, but presume you knew that. I must admit we do notice a slight
decrease in flam on the gas cooker when the boiler comes on but think its
due to the fact the boiler has a greater requirement for gas and is comes
before the hob in the pipe work.
Don't think its anything to worry about, unless your hob goes out everytime
your boiler starts but that's only my opinion.
"Seri" <saln...@gmail.com> wrote in message
news:1103136837.4...@f14g2000cwb.googlegroups.com...
Tony Bryer
<1103136837.4...@f14g2000cwb.googlegroups.com>, Seri
wrote:
> The problem now is that when the combi boiler fires for water
> or heating the hob flames get smaller. On individual rings
> it's not really noticeable, but on the large centre ring it's
> quite significant.
It sounds like the pipe supplying the hob and combi is
inadequate. The real danger would be if you set the hob to a
gentle simmer and the flame goes out when the combi cuts in.
--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm
Seri
then turned the heating up full and left the upstairs and downstairs
hot taps running (perhaps a tad over kill, but why take chances).
I then went around each burner turning it down to the smallest possible
flame (with the rest still on full), I left each burner on the lowest
setting for about a 1 minute each and tried blowing over them (hey, not
scientific, but still better than nothing).
Anyway, no burner went out, so I'm assuming this is no great shakes.
Correct?
Thanks again
Seri
Tony Bryer
<1103140231.2...@z14g2000cwz.googlegroups.com>, Seri
wrote:
Not quite the right test IMO: you need to have the hob burners on
the lowest possible setting *before* you fire the boiler. The risk
is that the combi firing up drops the pressure at the hob to below
what is required to sustain a flame.
Seri
extinguish before turning the individual burners down, then let it fire
again. I also tried turning all the boilers down to minimum and firing
the boiler.
No flames extinguished, but when all 4 burners and the central fish
kettle/griddle burner were on full the boiler firing had quite a
noticeable effect on the flame size.
The gas piping from the meter to the boiler is 22mm copper and to the
hob is 15mm copper. I'm speculating that the piping to the hob needs to
be replaced with 22mm the same as the boiler.
Thanks again for all your help, it's really appreciated.
Seri
Andy
http://www.ukcopperboard.co.uk/public/howcanwehelp/inst_tips3_contents_list.
shtml and click on pipe sizing. What you should aim to achieve is a 1 mb or
less drop in pressure from the meter to the appliance, any more than that
and you are asking for problems, the main one being incomplete combustion,
which creates carbon monoxide.
Andy
"Seri" <saln...@gmail.com> wrote in message
news:1103141751....@z14g2000cwz.googlegroups.com...
Lurch
together this:
>The gas piping from the meter to the boiler is 22mm copper and to the
>hob is 15mm copper. I'm speculating that the piping to the hob needs to
>be replaced with 22mm the same as the boiler.
>Thanks again for all your help, it's really appreciated.
>
Although there are plenty of others here who will be able to advise
you better, I haven't actually seen a hob that needs 22mm.
I think if anything you need to upgrade the run from the meter to the
hob tee off up to 28mm. I would advise you to call in a CORGI
registered installer at this point.
--
SJW
Please reply to group or use 'usenet' in email subject
Seri
using a manometer (0 mbar) but after reading some of the PDF's on that
extremely informative site (thanks Andy) I've realised that I never
tested the dynamic pressure drop. Am going to get the manometer out now
and test the dynamic pressure drop to see if it's more than 1.25mbar.
Thanks again for all the advice
Seri
Mike
"Derek Doormer" <Der...@yahoo.co.uk> wrote in message
news:cpq1m8$ktr$1...@news8.svr.pol.co.uk...
> Firstly if its a fixed hob this should be fitted by a registered CORGI
> fitter, but presume you knew that.
Not true. It is quite legal to replace a gas appliance in your own premises
provided you do it competently.
Seri
I just ran through some tests at the meter test point using a
manometer.
The standing pressure with the boiler and hob isolation valves closed
is 24.8mbar
The standing pressure with the boiler and hob isolation valves open is
24.8mbar
When the boiler fires the pressure drops to 9mbar, and whilst the
boiler is heating this stays at 9mbar. When the boiler stops the
pressure returns.
Am I right in assuming that this means there is a problem with meter
govenor and I need to call transco out?
Thanks again for all this advice.
Seri
Ed Sirett
I take it that you've read the FAQ. ?
It might be that the old cooker was more tolerant of pressure variations.
You need to find out where the big changes of pressure are coming from. It
even be that the main governor is failing.
It is also just as possible that you have inadequate installation
pipework.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Ed Sirett
> Okay, after my testing I'm now more flummoxed and concerned than ever.
>
> I just ran through some tests at the meter test point using a
> manometer.
>
> The standing pressure with the boiler and hob isolation valves closed
> is 24.8mbar
>
> The standing pressure with the boiler and hob isolation valves open is
> 24.8mbar
That just shows there is a reasonable supply of gas before the main
governor.
> When the boiler fires the pressure drops to 9mbar, and whilst the
> boiler is heating this stays at 9mbar. When the boiler stops the
> pressure returns.
And that was at the meter outlet. There is something very wrong
with the meter, governor or service pipe. Time to call TRANSCO 0800 111999
IMM
Take the hob supply right back to the meter.
IMM
> Firstly if its a fixed hob this should be fitted by a registered CORGI
> fitter, but presume you knew that.
It doesn't!! He has to "competent".
IMM
If the hob pipe goes right back to the meter, then either:
1. Check the supply pipe size to the hob. If undersized then replace a
part of it with 22mm.
2. Get Transco in. Sounds as if the regulator/supply is suspect.
Seri
I just had Transco in and they've confirmed there's a problem with the
supply, they changed the regulator but that's not the problem. It seems
that when they replaced all the pipes in this street about a month
back, they may have put a kink or some slight blockage in our supply by
accident.
Either way, our gas is now capped off, and Transco are supposed to be
out to dig up out street again in a little while.
So, once again, a huge thank you to everyone on the group for helping
me troubleshoot this and find a solution.
Thanks again
Seri
IMM
"Ed Sirett" <e...@makewrite.demon.co.uk> wrote in message
news:pan.2004.12.16...@makewrite.demon.co.uk...
> On Wed, 15 Dec 2004 13:47:13 -0800, Seri wrote:
>
> > Okay, after my testing I'm now more flummoxed and concerned than ever.
> >
> > I just ran through some tests at the meter test point using a
> > manometer.
> >
> > The standing pressure with the boiler and hob isolation valves closed
> > is 24.8mbar
> >
> > The standing pressure with the boiler and hob isolation valves open is
> > 24.8mbar
>
> That just shows there is a reasonable supply of gas before the main
> governor.
A reasonable "pressure". The supply is the flow, which is not there.
Amanda
Ananda
--
For full context, visit https://www.homeownershub.com/uk-diy/when-boiler-fires-hob-flames-go-down-133952-.htm
chop
<6d628c52a7f7a97b...@example.com> wrote:
> We have the opposite problem our gas hob won't light until the heating
> kicks in
Peeler
senile geezer Rodent Speed, wrote:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
Xeno to senile Rodent:
"You're a sad old man Rod, truly sad."
MID: <id04c3...@mid.individual.net>
Andrew
> We have the opposite problem our gas hob won't light until the heating
> kicks in
> Ananda
>
Brian Gaff
house that jack built type web forums was cut.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"chop" <cho...@gmail.com> wrote in message
news:op.1xc59...@pvr2.lan...
John Rumm
> kicks in
--
Cheers,
John.
/=================================================================\
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\=================================================================/
Rod Speed
> Yes well, its about time those in charge of allowing access to usenet
Peeler
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
"Surely you can find an Australian group to pollute rather than posting
your unwanted guff here."
MID: <c1pqvgte5ldlo1rn3...@4ax.com>
Loose Cannon
Peeler
married gay neo-nazitard, whined again:
cretin for what you are, Loose Sphincter! Just like your anti-virus provider
exposed you for the "neo-Nazi scum" that you are. LOL
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Animal
> We have the opposite problem our gas hob won't light until the heating kicks in
> Ananda
Andrew Gabriel
> kicks in
holes/groves. If they're partially blocked, gas velocity will be
incorrect which often causes lighting problems, and flame lift-off.
If that doesn't fix it, you need a gas engineer to check the gas
pressure, and pressure drop under load, and maybe adjust the hob burner
rates. One appliance significantly affecting the pressure at another
appliance might suggest undersized pipework, gas regulator not working
correctly, or insufficient gas supply.
Andrew