On 01/06/2012 13:56, David WE Roberts wrote:
One of the things we bought from Ikea :-)

Burners a
4kw
3kw
2kw * 2
1 kw

So in theory the maximium demand for the hob 15 minutes before a dinner
party and everything running late is 10Kw.
Is this likely to have a major impact on the size of the gas supply pipe
and will it suck gas backwards through the combi :-)

No, but you will need to make sure the pipework is sized correctly.

Seriously, will a 15mm supply be O.K.?

Depends on the (effective) length...

Looks like we will be running a seperate new feed to the combi.

Perhaps.

Do the sums, then you will know.

BS 6891 page 34 has a fully worked example and all the tables you need
(if you have a Elan library card you can probably download it from your
local library's web site), if not then doa web search for the copper
development association sizing guide (same info - repackaged), or drop
me an email and I can tell you where to find a copy of the BS.


--
Cheers,

John.

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"John Rumm" wrote in message
o.uk...
On 01/06/2012 13:56, David WE Roberts wrote:
One of the things we bought from Ikea :-)

Burners a
4kw
3kw
2kw * 2
1 kw

So in theory the maximium demand for the hob 15 minutes before a dinner
party and everything running late is 10Kw.
Is this likely to have a major impact on the size of the gas supply pipe
and will it suck gas backwards through the combi :-)

No, but you will need to make sure the pipework is sized correctly.

Seriously, will a 15mm supply be O.K.?

Depends on the (effective) length...

Looks like we will be running a seperate new feed to the combi.

Perhaps.

Do the sums, then you will know.

BS 6891 page 34 has a fully worked example and all the tables you need (if
you have a Elan library card you can probably download it from your local
library's web site), if not then doa web search for the copper development
association sizing guide (same info - repackaged), or drop me an email and
I can tell you where to find a copy of the BS.


Thanks - just to note that the seperate feed is not anything to do with pipe
sizing but to do with the proposed new boiler location.
Plan is to use the existing gas pipework (under suspended ground floor feeds
a gas fire in the lounge which will be removed and the current boiler in the
kitchen) to feed the new hob in the new kitchen.
A new supply will be run down the outside of the house and in under the
first floor to the airing cupboard where the new combi will be situated.
[Today's plan - may yet change again.]

Looking at BTU/kW conversions I read that to convert kW to BTU you multiple
by 3414.
That makes a 10kW stove at full chat equivalent to a 34140 BTU boiler if I
have got the numbers right.
Looking at the sticker inside out Stelrad Ideal W2000 R60 I see that it
pulls 23.4 kW (80,000 BTU) max so the current pipework should handle the gas
hob on its own.

So the only issue would be the total capacity of the meter - heating
engineer to check :-)

Original post was fairly lighthearted - prompted by the fact that the hob
was a lot bigger than average and had caused me to wonder if this would have
an impact.

Cheers

Dave R
--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

(\__/)
(='.'=)
(")_(")

On 02/06/2012 10:07, David WE Roberts wrote:

"John Rumm" wrote in message
o.uk...
On 01/06/2012 13:56, David WE Roberts wrote:
One of the things we bought from Ikea :-)

Burners a
4kw
3kw
2kw * 2
1 kw

So in theory the maximium demand for the hob 15 minutes before a dinner
party and everything running late is 10Kw.
Is this likely to have a major impact on the size of the gas supply pipe
and will it suck gas backwards through the combi :-)

No, but you will need to make sure the pipework is sized correctly.

Seriously, will a 15mm supply be O.K.?

Depends on the (effective) length...

Looks like we will be running a seperate new feed to the combi.

Perhaps.

Do the sums, then you will know.

BS 6891 page 34 has a fully worked example and all the tables you need
(if you have a Elan library card you can probably download it from
your local library's web site), if not then doa web search for the
copper development association sizing guide (same info - repackaged),
or drop me an email and I can tell you where to find a copy of the BS.


Thanks - just to note that the seperate feed is not anything to do with
pipe sizing but to do with the proposed new boiler location.
Plan is to use the existing gas pipework (under suspended ground floor
feeds a gas fire in the lounge which will be removed and the current
boiler in the kitchen) to feed the new hob in the new kitchen.
A new supply will be run down the outside of the house and in under the
first floor to the airing cupboard where the new combi will be situated.
[Today's plan - may yet change again.]

Looking at BTU/kW conversions I read that to convert kW to BTU you
multiple by 3414.
That makes a 10kW stove at full chat equivalent to a 34140 BTU boiler if
I have got the numbers right.
Looking at the sticker inside out Stelrad Ideal W2000 R60 I see that it
pulls 23.4 kW (80,000 BTU) max so the current pipework should handle the
gas hob on its own.

So the only issue would be the total capacity of the meter - heating
engineer to check :-)

A domestic U6 meter should do 6m^3 / hour or 64kW / 220 kBTUs

Original post was fairly lighthearted - prompted by the fact that the
hob was a lot bigger than average and had caused me to wonder if this
would have an impact.


Compared to a boiler its at the smaller end of what you could buy. So
swapping one for the other should be fine assuming the original
installation was to spec.

The time that big hobs etc may pose a problem is when attempting to
build a dribble style system with two combis and spare multipoint water
heater for the outside loo.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/