I have an all-gas cooker with six hobs and one large oven. However, it
can't cope with having all of these on at once - even three hobs sees
the flames on each reduced dramatically from their one-at-a-time sizes.
I guess this could be a restriction either inside the cooker itself, or
in the supply. In the former case, no problem, as I've just forked out
for a new cooker to be delivered in ten days or so (the current one is a
bit crap). However, there is the possbility that the fault is in the
house piping, or a deficiency in the actual supply.

The pipe is hidden behind the cooker, which I don't really want to pull
out just yet. However, I can see into the space from one side, and it
looks like there are two sizes of pipe in there. It emerges at a larger
diameter (maybe 3/4") but for the last foot or so before the connection
to the cooker, it's reduced to a smaller size more like radiator pipes
(sorry about the vagueness of the sizes, but it's a little while since I
last squinted through that gap. I guess there aren't that many sizes of
gas pipe in use anyway.) Is this normal? Likely to be a problem? I would
have thought that the tubing inside a cooker is pretty small anyway.

Any advice welcome.

Pete

Pete Verdon wrote:
I have an all-gas cooker with six hobs and one large oven. However, it
can't cope with having all of these on at once - even three hobs sees
the flames on each reduced dramatically from their one-at-a-time sizes.
I guess this could be a restriction either inside the cooker itself, or
in the supply. In the former case, no problem, as I've just forked out
for a new cooker to be delivered in ten days or so (the current one is a
bit crap). However, there is the possbility that the fault is in the
house piping, or a deficiency in the actual supply.

The pipe is hidden behind the cooker, which I don't really want to pull
out just yet. However, I can see into the space from one side, and it
looks like there are two sizes of pipe in there. It emerges at a larger
diameter (maybe 3/4") but for the last foot or so before the connection
to the cooker, it's reduced to a smaller size more like radiator pipes
(sorry about the vagueness of the sizes, but it's a little while since I
last squinted through that gap. I guess there aren't that many sizes of
gas pipe in use anyway.) Is this normal? Likely to be a problem? I would
have thought that the tubing inside a cooker is pretty small anyway.

From the info given I'd say the most likely culprit is the piping in
your house. It sounds like it's done mostly in 15mm tubining (that's
the next size down from the 22mm or 3/4" which you can see). What
happens at the gas meter end of the tube, by the way - presumably you
can see the tube diameter there?

Although there will be very small tubing withing the oven, yes - it's
all about the overall length of the narrow tubing which the gas flows
through as that's what determines the resistance to the flow. If
there's only a very short distance between the incoming pipe at the gas
meter and your oven - and there's nothing else fed with gas eg a boiler
or fire - you'd probably get away with a 15mm pipe.

I've seen a rule-of-thumb pipe size calculator posted here before but
can't find it - hopefully someone else will know?

David

Lobster wrote:
Pete Verdon wrote:
I have an all-gas cooker with six hobs and one large oven. However,
it can't cope with having all of these on at once - even three hobs
sees the flames on each reduced dramatically from their
one-at-a-time sizes. I guess this could be a restriction either
inside the cooker itself, or in the supply. In the former case, no
problem, as I've just forked out for a new cooker to be delivered
in ten days or so (the current one is a bit crap). However, there
is the possbility that the fault is in the house piping, or a
deficiency in the actual supply. The pipe is hidden behind the cooker,
which I don't really want to
pull out just yet. However, I can see into the space from one side,
and it looks like there are two sizes of pipe in there. It emerges
at a larger diameter (maybe 3/4") but for the last foot or so
before the connection to the cooker, it's reduced to a smaller size
more like radiator pipes (sorry about the vagueness of the sizes,
but it's a little while since I last squinted through that gap. I
guess there aren't that many sizes of gas pipe in use anyway.) Is
this normal? Likely to be a problem? I would have thought that the
tubing inside a cooker is pretty small anyway.

From the info given I'd say the most likely culprit is the piping in
your house. It sounds like it's done mostly in 15mm tubining (that's
the next size down from the 22mm or 3/4" which you can see). What
happens at the gas meter end of the tube, by the way - presumably you
can see the tube diameter there?

?? From what the OP's said, it sounds like 22mm up to the last foot when
it's reduced to 15mm. Seems unlikely then that the system from the meter
goes from 22mm to 15mm and back to 22mm before reducing to 15mm at the very
end.

Tim

"Tim Downie" wrote

?? From what the OP's said, it sounds like 22mm up to the last foot when
it's reduced to 15mm. Seems unlikely then that the system from the meter
goes from 22mm to 15mm and back to 22mm before reducing to 15mm at the
very end.

Tim

Would be useful to know:
The pipe route/length and number of elbows from the meter
Was there another heavy user on line when the tests were carried out?
Have there been performance issues with other users eg boiler?


Phil

Tim Downie wrote:
Lobster wrote:
Pete Verdon wrote:
I have an all-gas cooker with six hobs and one large oven. However,
it can't cope with having all of these on at once - even three hobs
sees the flames on each reduced dramatically from their
one-at-a-time sizes. I guess this could be a restriction either
inside the cooker itself, or in the supply. In the former case, no
problem, as I've just forked out for a new cooker to be delivered
in ten days or so (the current one is a bit crap). However, there
is the possbility that the fault is in the house piping, or a
deficiency in the actual supply. The pipe is hidden behind the cooker,
which I don't really want to
pull out just yet. However, I can see into the space from one side,
and it looks like there are two sizes of pipe in there. It emerges
at a larger diameter (maybe 3/4") but for the last foot or so
before the connection to the cooker, it's reduced to a smaller size
more like radiator pipes (sorry about the vagueness of the sizes,
but it's a little while since I last squinted through that gap. I
guess there aren't that many sizes of gas pipe in use anyway.) Is
this normal? Likely to be a problem? I would have thought that the
tubing inside a cooker is pretty small anyway.
From the info given I'd say the most likely culprit is the piping in
your house. It sounds like it's done mostly in 15mm tubining (that's
the next size down from the 22mm or 3/4" which you can see). What
happens at the gas meter end of the tube, by the way - presumably you
can see the tube diameter there?

?? From what the OP's said, it sounds like 22mm up to the last foot when
it's reduced to 15mm. Seems unlikely then that the system from the meter
goes from 22mm to 15mm and back to 22mm before reducing to 15mm at the very
end.

Yep - true enough. Sorry, misread the OP!

David

TheScullster wrote:

Would be useful to know:
The pipe route/length and number of elbows from the meter

Don't know, unfortunately. As the crow flies it's maybe 20, 25 feet, but
I have no idea of the route. I suspect it's buried in the concrete
floor, but there has been an extension between the meter and the cooker
(though those are both in original parts of the house) so anything could
have happened.

Was there another heavy user on line when the tests were carried out?
Have there been performance issues with other users eg boiler?

The only other gas appliances are a living room fire (which I never use)
and a smallish combi-boiler. I haven't noticed any issues with the boiler.

I haven't specifically tested the cooker with the boiler off, but it's
likely that it would have been off at least some of the times that I've
used the cooker, and I haven't noticed any significant variation.
Interesting idea though - I guess if I turn the cooker on when the
boiler is on, then go and turn the boiler off, I could compare the flame
size on the cooker. If it doesn't change, then that suggests that the
incoming supply is unlikely to be the bottleneck.

Pete

"Pete Verdon" d wrote in
message ...
TheScullster wrote:

Would be useful to know:
The pipe route/length and number of elbows from the meter

Don't know, unfortunately. As the crow flies it's maybe 20, 25 feet, but I
have no idea of the route. I suspect it's buried in the concrete floor,
but there has been an extension between the meter and the cooker (though
those are both in original parts of the house) so anything could have
happened.

Was there another heavy user on line when the tests were carried out?
Have there been performance issues with other users eg boiler?

The only other gas appliances are a living room fire (which I never use)
and a smallish combi-boiler. I haven't noticed any issues with the boiler.

I haven't specifically tested the cooker with the boiler off, but it's
likely that it would have been off at least some of the times that I've
used the cooker, and I haven't noticed any significant variation.
Interesting idea though - I guess if I turn the cooker on when the boiler
is on, then go and turn the boiler off, I could compare the flame size on
the cooker. If it doesn't change, then that suggests that the incoming
supply is unlikely to be the bottleneck.

Pete

have you had a new gas pipe to the meter as done by transco? our area has
and all they do is line the old pipes with new plastic making it a smaller
supply line to the house.

Dave

dave wrote:

have you had a new gas pipe to the meter as done by transco? our area has
and all they do is line the old pipes with new plastic making it a smaller
supply line to the house.

Not while I've had the house, but that's only six months. However, the
house is 1990s, so I wouldn't have thought the pipes would have needed
replacing yet.

Pete

Hi
Had a similar problem 2yrs ago with a range cooker ended up having to repipe
in 28mm to solve problem.
IIR gas needs volume not pressure to work so the piping change restricts the
flow.
Most instalations leave the meter in either 28 or 22mm copper then reduce to
15mm for the cooker outlet but continue in 22mm to the CH boiler if it
further away.

HTH

CJ

On Sun, 10 Feb 2008 23:53:51 +0000, Pete Verdon wrote:

I have an all-gas cooker with six hobs and one large oven. However, it
can't cope with having all of these on at once - even three hobs sees
the flames on each reduced dramatically from their one-at-a-time sizes.
I guess this could be a restriction either inside the cooker itself, or
in the supply. In the former case, no problem, as I've just forked out
for a new cooker to be delivered in ten days or so (the current one is a
bit crap). However, there is the possbility that the fault is in the
house piping, or a deficiency in the actual supply.

The pipe is hidden behind the cooker, which I don't really want to pull
out just yet. However, I can see into the space from one side, and it
looks like there are two sizes of pipe in there. It emerges at a larger
diameter (maybe 3/4") but for the last foot or so before the connection
to the cooker, it's reduced to a smaller size more like radiator pipes
(sorry about the vagueness of the sizes, but it's a little while since I
last squinted through that gap. I guess there aren't that many sizes of
gas pipe in use anyway.) Is this normal? Likely to be a problem? I would
have thought that the tubing inside a cooker is pretty small anyway.

Any advice welcome.

Pete

What's happening at the outlet of the gas meter? with a bit of luck the
governor's shot and the whole problem is NG Transco's.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

cj wrote:

Had a similar problem 2yrs ago with a range cooker ended up having to repipe
in 28mm to solve problem.

Sounds ominous. The new cooker, though a range type, has electric ovens
and grill (I hated the gas ones in the old cooker - seemed so
primitive). Hopefully no major replumbing will be necessary to get five
rings working properly.

Treading on slightly sensitive ground, is cutting off the 15mm extension
and fitting a (presumably bayonet) connector to the 22mm something
that's DIYable? If this were water I'd be at it without a second
thought, but are there any special considerations for gas? What type of
fittings are used (solder, compression, etc)? I realise there's an
argument that says that if I have to ask such questions I shouldn't be
doing it, but one has to start somewhere.

Pete

Pete Verdon wrote:
cj wrote:

Had a similar problem 2yrs ago with a range cooker ended up having
to repipe in 28mm to solve problem.

Sounds ominous. The new cooker, though a range type, has electric
ovens and grill (I hated the gas ones in the old cooker - seemed so
primitive). Hopefully no major replumbing will be necessary to get
five rings working properly.

I would have thought that if it's only 5 rings *no* replumbing should be
necessary. Surely it must have worked properly when installed (although I
appreciate that you don't know this)?

Makes me think that the pressure regulator by your meter isn't doing its job
properly.

Tim

Ed Sirett wrote:

What's happening at the outlet of the gas meter? with a bit of luck the
governor's shot and the whole problem is NG Transco's.

I didn't see anything of note when I read the meter the other day. What
should I be looking for?

Pete

Pete Verdon wrote:
Ed Sirett wrote:

What's happening at the outlet of the gas meter? with a bit of luck
the governor's shot and the whole problem is NG Transco's.

I didn't see anything of note when I read the meter the other day.
What should I be looking for?

You won't see anything at all on the meter. It's the pressure that seems to
be lacking in your pipework and that'll have to be tested with a suitable
gauge.

From what you've said it's clear that not enough gas is getting to your 5
ring hob. Also, from your desription of the pipework, that doesn't sound
like it the source of the problem either.

That leaves either a problem with your hob (possible sticking shut off valve
if it has a closing lid) or a lack of supply pressure. If your cooker has a
lid I'd try working it open & closed a few times to see if that frees
anything up. If it doesn't have a shut off valve, I'd suspect that your
pressure regulator by the meter is faulty which, as Ed says, is Transco's
problem to sort out.

Tim

Tim Downie wrote:

From what you've said it's clear that not enough gas is getting to your 5
ring hob. Also, from your desription of the pipework, that doesn't sound
like it the source of the problem either.

That leaves either a problem with your hob (possible sticking shut off valve
if it has a closing lid) or a lack of supply pressure. If your cooker has a
lid I'd try working it open & closed a few times to see if that frees
anything up. If it doesn't have a shut off valve, I'd suspect that your
pressure regulator by the meter is faulty which, as Ed says, is Transco's
problem to sort out.

Thanks - a useful summary. There's no lid valve on the cooker as it's a
range type appliance. It's being replaced anyway. I reckon the thing to
do is take a manometer reading while I'm disconnecting it, hoping that
that's good and it's the cooker that's faulty. If it's not, I can
connect up the new cooker anyway, and then call Transco to sort out the
regulator.

Pete

On Tue, 12 Feb 2008 12:40:57 +0000, Pete Verdon wrote:

Ed Sirett wrote:

What's happening at the outlet of the gas meter? with a bit of luck the
governor's shot and the whole problem is NG Transco's.

I didn't see anything of note when I read the meter the other day. What
should I be looking for?

Pete

Read the gas fitting faq. There's more to gas meters than the reading 8-)


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On Tue, 12 Feb 2008 17:13:03 +0000, Pete Verdon wrote:

Tim Downie wrote:

From what you've said it's clear that not enough gas is getting to your
5 ring hob. Also, from your desription of the pipework, that doesn't
sound like it the source of the problem either.

That leaves either a problem with your hob (possible sticking shut off
valve if it has a closing lid) or a lack of supply pressure. If your
cooker has a lid I'd try working it open & closed a few times to see if
that frees anything up. If it doesn't have a shut off valve, I'd
suspect that your pressure regulator by the meter is faulty which, as
Ed says, is Transco's problem to sort out.

Thanks - a useful summary. There's no lid valve on the cooker as it's a
range type appliance. It's being replaced anyway. I reckon the thing to
do is take a manometer reading while I'm disconnecting it, hoping that
that's good and it's the cooker that's faulty. If it's not, I can
connect up the new cooker anyway, and then call Transco to sort out the
regulator.

If the boiler is working OK, and specifically if the boiler coming on
does not noticeably affect the hob flames the the problem is with the
range-cooker. One possibility is that the bayonet connector is only half
in, enough to seal but not enough to latch and more importantly depress
the button inside the connector. As a result you not got a good enough
gas supply to the range cooker.

You really need to attach a manometer (around £20 or make yourself if you
have /lot/ more time than money) to the gas meter outlet test point.
Then record the pressure as you go from 1 to 6 rings alight and/or boiler
You should find that the pressure will drop a bit but should stay in the
range 19-23 mbar whatever the flow rate.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Ed Sirett wrote:
One possibility is that the bayonet connector is only
half in, enough to seal but not enough to latch and more importantly
depress the button inside the connector. As a result you not got a
good enough gas supply to the range cooker.

Ah, I hadn't thought of that one. Good one to remember.

Tim

Hi
agree with later repies 5 rings should be fine on 15mm my cooker had 8 plus
2 ovens so really ate the gas.

You say house is 90's? so lead gas piping is out.
As sugested suspect regulator or (if the meter is under the stairs or
obstructed) check the gas valve is fully on.(I know this seems basic but had
a case when kids pushed cases under stairs catching gas valve turning it
off)
Or look for damage to the piping ,has it been crushed?

As has been said the easiest way is to use a manometer at the cooker .
As for your other question gas fitters solder connections and also use
compression fittings.Normally compression is only used where accessable but
have heard of a pushfit used on propane (don't know if its legal or safe
though)
HTH

CJ