Gas cooker problem

[chadspad]

Can anyone help me please? I have a gas cooker (Ariston) that is run with bottled gas. It has been fab for over 3 years now all of a sudden the oven part is playing up. You ignite the burners with a push button - the burners on the top are all fine but the oven burners, although coming on and staying on as long as u have the knob pressed in, turns off immediately u take your hand off! Typically cant find the manual ANYWHERE and having searched the internet for the Ariston site, it appears they dont make cookers! So thought I'd ask you knowledgeable bunch before having to call someone in. Hubby has taken it apart and cleaned all of it, thats made no difference.
Please help!

[marshlander]

OH suggests it's the thermocouple on the gas valve that may have gone.

Pressing the button alows a small amount of gas through the pilot and the spark ignites it. The heat heat of this small flame heats up the thermocouple which opens the main gas valve and ignites the burners from the pilot flame.

Ariston are made by indesit.
Hope this helps

[chadspad]

Thats really helpful, thanks very much. We have some spare bits (somewhere!) will dig them out and try that. Love your avatar!
Thanks again!