DIYbanter - View Single Post - 50+ year-old gas cooker with stiff gas taps

Fred

wrote:
On Feb 22, 6:30 pm, cynic wrote:
On 22 Feb, 18:08, wrote:

The New World seventy-six cooker I have needs the taps / knobs
lubricating - I saw something on a previous post suggesting gss cock
grease. Is this the stuff, and is it straightforward to dismantle
and re-grease them? A gas engineer I spoke to muttered darkly about
carbon monoxide and said any engineer would charge £100 to come out
and then slap a condemned label on it to cover himself. I like the
cooker but like life more - should I think of scrapping it for
safety? The flame on one burner was a little yellow, to I closed
what I took to be an air inlet screw on the cast iron pipe leading
to it - this improved it but even fully tightened the flame is
still a little yellow. Would re- greasing the taps help this - and
should I be in there at all? Thanks for advice.
Peter

Greasing gas taps is relatively simple, do not use excessive amounts
of grease or you may clog the injector and bypass ports. As with all
such jobs you really ought to have the facility to check the cock is
closing of correctly and does not leak around the barrel on
completion (a little leak detector spray might be a reassurance
here) With respect to the yellow flame, a thorough clean out of the
air inlet, burner mixing tube and the burner head may work wonders.
Your screw adjustment needs a bit more clarification. Is it a screw
which projects into the mixing tube? If so the effect of screwing it
in is to create a resistance to the flow of gas and air from the
injector jet to the burner and would tend to soften the flame by
reducing the airflow. Less air, same amount of gas will tend to
cause yellowing of the flame not reduce it. On an old burner scaling
and corrosion may be causing a restriction within the casting. Try a
stiff baby bottle brush or similar

Thanks for all that. I will see if I can get hold of some gas cock
grease and give it a go...What I described as 'adjusting screws' are
located on the top of the mixing tubes, just behind the taps. I'd
assumed they were to adjust the gas / air mix, but from what you are
saying that is not really correct. I am wondering what their purpose
is? I will start with a thorough clean as you suggest and go from
there.

My biggest concern is the yellow flame. It is indicative of a incorrect
air/gas mixture. If you've opened the air inlet screw wide open, the next
thing you can look at is the burner. I guess it's made of cast iron in
which case you'll probably find rust has closed the gaps to restrict the
flow of mixture leaving the burner. The offending burners should be removed
and the slots cleared. You might also find the slots are coated with dried
household cleaners.

I'm sure some here would frown, but generally if you have a blue flame,
you've got complete combustion with little or no carbon monoxide being
generated.