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John Rumm John Rumm is offline
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Default Fitting a gas hob and oven

On 25/03/2014 23:21, Fredxxx wrote:
On 25/03/2014 15:28, John Rumm wrote:
On 25/03/2014 00:49, Fredxxx wrote:
On 25/03/2014 00:05, John Rumm wrote:
On 24/03/2014 17:50, Fredxxx wrote:
These are to be fitted in a work surface and a kitchen unit.

I want to do the job right such that if inspected there won't be any
issues later.

I've read:
http://wiki.diyfaq.org.uk/index.php?...as_fitting_FAQ
but its a bit quiet in certain areas though gives a good indication of
determining leak-rate.

Where possible I was going to use end-feed fittings, though the only
demountable fittings I can get are of the compression variety. In the
past I have been able to source gas union joints. Is this OK to use
compression joints if at the back of the units and under the work
surface? Will they be deemed as accessible?

You can use compression joints or solder. Do you particularly need them
to be demountable?

Many ovens will use a flexible hose for the final connection with a
normal bayonet connector.

Hobs (contrary to popular belief) can also use flexible hoses, or
can be
rigid piped. The final connection the hob usually being a gas union
nut,
such that it can be disconnected there.

I understand there ought to be a means of isolating the hob and
oven. Is
it acceptable for this to be a single valve for both appliances. There

Yes, I believe so.

are "Fan Key Gas Cock"s and "Isolating Gas Ball Valve. Which should I
use? I can get the Fan Key Gas Cock in a capillary form, but of
course
that will require dismantling and reassembly with new grease. I don't
have the proper grease at hand, will alternatives be OK?

A lever ball valve is the most commonly used IME.

I'd appreciate any guidance.

(I am not a professional gas fitter - so seek confirmation of the
above)

Many thanks.

I was aware that flexible pipe can be used, but presumed that a bayonet
fitting behind or underneath kitchen unit would be against form!


As long as you can get to it to make or break the connection then its
quite normal. In the case of an oven they will often have a bayonet
fitting in the back of the unit that you can only get to when the oven
is pulled out.


Thanks, that would be the easiest option.

I also
thought it was forbidden where a hob is above an oven?


Hobs are more traditionally plumbed in 15mm copper anyway in cases where
you can get to the underside of it once its fitted. (even if that means
the oven needs to go in second).


With the oven removed I could connect underneath as you say, but it
would result in a compression elbow, or possibly coupler.

Gas Union Nuts seem to be rather rare beasts and not sold by the likes
of Screwfix and not mentioned on some of the more tradition plumbers'
merchants websites?


They are typically just BSP female threaded sockets. Sometimes normal
compression fittings. They hob will often come with the fitting anyway.


The hob has a male 1/2" BSP.


Is it a taper fitting (probably)? If so a parallel BSP female to 15mm
compression would be fine. If its a parallel male then a taper BSP
female. Make the joint with gas grade PTFE or suitable jointing compound.

http://wiki.diyfaq.org.uk/index.php?...rappingGas.png

Then you can put the BSP adaptor on the hob, test fit it and pipe up the
rigid pipe. Then all you need do on final fitting is make the last
compression joint between pipe and adaptor, and test.

The isolation valve can go elsewhere where it will be more accessible.
Although there is no requirement for one on the bayonet fitting for the
oven, its unlikely to hurt in a domestic environment if it also isolates
that.

I think you may be overcomplicating things... bayonet socket on the back
wall behind the oven cabinet, then 15mm copper piping round to the right
place for the hob inlet with a 15mm leaver ball valve inline.


Sounds a good plan. I note the bayonet socket should be pointing down to
stop crud entering, but it would also result in a gentle U behind the oven.


The down pointing bit is of most importance with free standing cookers,
but its the normal approach. A gentle U is ideal since it does not
stress the hose or connections.


--
Cheers,

John.

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