problems with Smeg P75 72cm Gas Hob

[ifoto]

Hi,

Been a lurker here for a while and found some good solutions...after a quick search I couldnt find anything covering my current problem.

I have a 5 ring gas hob (Smeg P75 72cm)... the problem is a number of the rings light eventually (after 3 or 4 goes) and keep burning. However as soon as a pan is placed over the heat the burner turns off.

The ignition points are clean as are the things that check the temperature...so im at a loss, why would they turn off as soon as a pan is placed over the heat?

Hoping someone can offer some insight!

Ian

Untitled

• ifoto
• 20 Apr 2011
• 1

 

[ifoto]

Not sure why Ive been moved to this section but lets see what happens!!

 

[carlsquires]

when the flame goes out can you still hear gas coming out (if only for a short time)?

 

[ifoto]

No there is a definite click from the control knob then it all goes off. From what I understand this is the safely cut off but I have no idea why this would happen only when pan is placed on the ring. If i dont put a pan on it will burn away quite happy.

 

[carlsquires]

"the thing that checks the temperature" is the thermocouple, the flame needs to touch this in order to keep the valve open. When you put the pan on does the flame still touch on the thermocouple?

 

[ifoto]

I'd have to do some testing but I've no reason to believe it isn't. The pan is placed on the pan stand which does some few millimetres above the thermocouple, can't see why the flame would be disturbed by this.

I will look into it tomorrow and see.

 

[expertgasman]

Is the flame burning nice ad blue. The obvious problem that springs to mind is vitiation, i.e. lack of oxygen.

 

[mickyg]

it needs cleaning. Get something thin to clean out the ports in the burner.

 

[ifoto]

it needs cleaning. Get something thin to clean out the ports in the burner.

All the holes in the gas spreader ring are clean and clear. The flame is strong, blue and touches the thermocouple when on.

As per the photo i admit the caps are dirty but then they have been a nightmare to keep clean from the start.

Going back to my original post, as the burner takes 3-4 goes before it will stay lit could this be an indication that the thermocouple is on the way out? and if so how tough are they to swap out?

Very much appreciate the suggestions and advice so far!

 

[peejaydoubleu]

There are four burners on our SMEG hob, one small, two medium and one large that we call Big Bertha - don't really know why!

The Big Bertha has been the root of much frustration over the years. She lights most times - but not always. Then she goes out. Not at a time that isn't important, ALWAYS when you're just finishing the rolling boil needed for jam, or flash frying some Chinese leaves. We ususally (and I know this is sad) finish the job by me pressing the knob just the right amount to let the gas out without activating the click-click-click piezzo-electric ingition. This usually works but I always think about the £1,000 price tag for this piece of...

I am an engineer but a lazy one. I have often thought about removing the thermocouple (which is clearly the offending component) but I always forget the thought just when I tuck into the chinese meal my wife has just prepared with me crouched beside her making up for Smeg's lamentable design and quality control.

Anyway... long story short - if you have found an answer to your problem please let us know, otherwise I might one day soon, tackle the thermocouple problem.

What happened to all the people that used to care about product design, useability and longeivity? Did they all move to Japan? Not to Toyota it appears...

 

[Agile]

I always thought the Smeg were pretty good.

The stainless steel seems good too.

Like everything else the T/C could fail and need replacing after a few years.

I have never had a call to go and repair one.

Tony

 

[mrfixitwithabighammer]

I have had exactly the same thing with my Smeg A1 concerto, (amongst many others) The cooker has proved to be the most unreliable piece of S**** that £2500 grand could buy. Never again. Internal fans fallen apart terrible wiring, has burnt out a couple of times and melted plastic connector blocks inside. Clock failed. the list goes on.. and this problem has plagued us for years. I am going to change the Thermocouples and see how i get on! wish me luck.

 

[ifoto]

Ok so its been a while since this issue has bugged me enough to look into it again but that I have.

I picked up a burner key from the espares or someone like that, removed the pan stands and using the key removed the part of the gas spreader that is mounted above the base of the unit.

This exposed the internal void of the unit without having to remove it from the work surface and disconnecting the gas etc. It also exposed the spark and the thermocouple cables. Regrettably these disappear off deeper into the unit and if needed to be replaced would require said disconnection etc.

So with no real chance of doing anything that might really effect the problem I gave the top of the spark and bit of a wire brush and cleaned the newly exposed surfaces where the two parts screw together before reassembling and feeling like id basically not achieved anything.

However to my surprise the burner that would not light would now fire up and stay lit with no encouragement or prolonged holding down of the spark or knob.

I believe I scared it into thinking I was going to take it apart so it thought it better behave or else.

Seriously though, other than a very light clean of the surfaces I had done nothing that should have effected the operation of the thermocouple or the gas cut off yet it solved the problem.

Since then I have had occasion to wave the burner key in anger a couple of times and each time it seems to solve the issue at least for a little while. I can only assume that the issue is something to do with very minor alignment corrections and crap build up. Me poking the spark and couple with a wire brush seems to do something even though there seems to be little or no crap brushed off before I put it back together.

Hope this helps someone in the future.