View Full Version : Fixing a gas hob burner

2nd Apr 2014, 13:33
Knowing that there are many smart technical chaps on this forum can anybody guide me in this one.

I have a Smeg hob with a wok burner in the middle. When I press in the tap to light it the spark device works and lights the gas, but when I release it the flame goes out again. It doesn't matter how long I leave the tap pressed in, when I release it, it goes out.

On a previous hob, non Smeg I adjusted the flame with the small brass screw that is visible when you take the knob off which usually worked, but trying this on the Smeg does not make a blind bit of difference.

Before I take a mortgage out to call in the gas man (and the subsequent five verses as Flanders and Swan sang) is there an easy way of adjusting the burner unit?

Many thanks

2nd Apr 2014, 13:41
No, but say 'Hello' for me when you pass the parachutist on the way up. ;)

2nd Apr 2014, 13:49
Could be a faulty thermocouple.

Manufacturers developed and installed a safety valve called a flame failure device for gas hobs and ovens. The safety valve depends on a thermocouple that sends a signal to the valve to stay open. If a draft blows out the flame or it goes out due to loss of gas pressure, the thermocouple cools and signals the valve to close, shutting off the gas supply.

2nd Apr 2014, 13:49
Clean it all very carefully, and if that doesn't make any difference, then call the smegman (lest your insurance be invalidated if your domestic world should happen to goeth WOOMPH).

I suspect the gasman is cheaper than the firefighters.

Is it the continued sparking that keeps it burning or just the depression of the knob? If you turn off the electric power and light with a match does it do the same?

2nd Apr 2014, 13:53
I have a Smeg hob

So do we.

Step One: make friends with everyone else with a Smeg of the same type.
Step Two: when they lose patience with their Smegs and throw them on the scrapheap*, spend a happy afternoon first removing the burners, sensors, pipes, wiring loom and clock from their machines.
Step Three: store all this "junk" in your garage. You will need it.
Step Four: make friends with the cute little girl in your local Smeg maintenance man's parts store, the one who can operate the microfishe machine. (Ours is called Maria, she's b--- good at finding parts).
Step Five: get her to copy all the fiches contaning parts, and give you the address of Smeg in Italy. You will need ALL the Smeg fiches as Smeg can't be bothered putting a number on any of their products and you will have to guess. Is it a cooker ? Is it a plane ? Is it superman ? Who knows.
Step Six: make frequent donations to the Vatican.

Now. You have a faulty sensor on your hob, it screws up from underneath and pokes out alongside the burner. It needs replacing. If you haven't followed Steps One to Six above - or even if you have - call out your local repairman. Let him cut himself on all the sharp unfinished edges inside (and sometimes outside) your Smeg. And find all the different screws with excitingly odd heads and threads, when they fall down inside your Smeg. What's the difference between flight MH370 and a Smeg cooker ? You are happy when a Smeg cooker vanishes.....

* Usually about three years from purchase. However it can take as long as twenty years (us) and as little as five minutes.

old,not bold
2nd Apr 2014, 14:10
Fit a new thermocouple flame sensor. Yours is bugg....broken.

Ah, wait one, that's what OFSO said.

I think.

2nd Apr 2014, 14:17
Another Smeg sufferer here. Great bit of kit when it works, but after 9 years we're on our fourth fan oven element. :*

Solid Rust Twotter
2nd Apr 2014, 15:08
Nothing in the name to give you a clue, was there?:}


Lon More
2nd Apr 2014, 15:48
It all makes work for the working man to do ...

Flanders and Swann - The Gas Man Cometh - YouTube

tony draper
2nd Apr 2014, 15:55
Gas is Chemistry,Electronics is Physics they should never be mixed.:uhoh:

2nd Apr 2014, 16:01
Was often said that a chemist was a decent cook with ambitions to be a physicist.

Although I really shouldn't have told T'Lad, when he was young, about the definition of a mathematician ('a physicist without opposable thumbs') since he then mentioned it to his Maths teacher. Who, apparently, wasn't over impressed.

tony draper
2nd Apr 2014, 16:35
Bro Draper bought a new gas fire a few years back that has a electronic ignition system,you press a button it beeps at you for ten second the a long beep then the pilot light ignites then another beep and if your lucky the fire lights,if it doesn't you have to wait thirty seconds before trying again,it has had about six new motherboards todate? a feckin gas fire with a motherboard? bloody lunacy.
If you cant light a gas fire with a match your buggad.
Asked the first engineer that appeared to fettle it (the first of many)what the hell all the beeping achieved,he told me with a hurt voice it was for blind folk,I would have though the feeling of warmth of the face would tell you the fire has lit.
Over engineered stupidity.

Lightning Mate
2nd Apr 2014, 17:02
Agreed Mister d.

My Mercedes doesn't even have a dipstick.

2nd Apr 2014, 18:56
Thank you for the varied replies. I think I shall follow the OFSO line when I have stopped smiling and call in a licensed bandit with a pipe wrench.

Yes the thing is over engineered, due to the "Regs" being so restrictive on what must be put into a gas stove these days. I remember my dad and I stripping down the gas stove of the house I grew up in, early sixties and we had the whole thing back together in the hour, and it worked. Nothing more than a clean of the jets as to quote "Albert" of Albert and the Lion fame "Touch hole were bunged up wi' rustů"

Thanks again all.

2nd Apr 2014, 22:33
Gas is Chemistry,Electronics is Physics they should never be mixed:p

Biology ?

tony draper
2nd Apr 2014, 22:38
That's what goes in the pan on top of the gas.:rolleyes:

3rd Apr 2014, 00:09
If you do not treat the flat plate burners with devoted care and unknown high temperature metal preservative, you will find yourself with the very difficult task of finding expensive replacement parts.

The oven did hold up -- except that a ring around a knob came unhooked from the inner retaining ring.

Expect to spend an entire day getting to that:uhoh:

3rd Apr 2014, 08:57
My Mercedes doesn't even have a dipstick.

Anyone else want to pick up this particular hostage to fortune? :p

Lon More
3rd Apr 2014, 11:51
My Mercedes doesn't even have a dipstick

They all do. It can be found behind the steering wheel

Hadn't seen Magnus' post

cockney steve
3rd Apr 2014, 13:38
Anyone with basic plumbing , engineering and electrical skills, is capable of fixing/fettling gas appliances....granted, lack of a sense of smell can make things a bit more laborious :}

Given that leaks are legislated INTO the regulations, trade-protectionism,closed-shop and CYA spring to mind.
Mr Crun's pic. is a typical demonstration of the results obtainable bya Darwin Candidate.

You'd smell, to the point of nausea, any concentration that is high enough to cause problems. Basic commonsense techniques as applicable to any fluids, gases and compressed-air,will see a sound installation......I am able to go to the bottled-gas distributor and get a bottle of dissolved Acetylene......under certain circumstances, this stuff can spontaneously combust ,just by giving the cylinder a sharp shock-blow.....yet, there are no mandatory handling, usage or understanding assessments....A single cylinder going off ,would make Henry's pic look like a twopenny banger on Guy Fawkes night...

I have found spares freely available from trade-counters ,on-line and major retailers like B&Q....Perfectly legal to sell or buy gas fittings and appliances from/to unqualified persons.


WRT Motherboards, there are specialist reworkers/repairers....even the eprom chips can often be copied, despite the OE manufacturer coating everything with black varnish or grinding the surface off the chips to remove the ID. They try hard to be as obstructive as possible and make you pay through the nose when often a 5 pence component is at fault -or even just a poor solder joint!

Restrictive trade practices are thriving, despite their supposed outlawing.
It's for your own good, Dontcha know?

3rd Apr 2014, 14:06
My Mercedes doesn't even have a dipstick.

Thread drift. Only three possibilities here:

- It fell out.
- It wasn't replaced by the last person to measure the oil level.
- It broke off flush with the hole it fits in.

Even dry sump cars (in my experience) have a measuring device in the oil tank.

Lightning Mate
3rd Apr 2014, 14:13
None of the above.

One has to select "check engine oil" from the computer menu providing the engine has not run for ten minutes. I you try it in less than that time it tells you to wait.