Smeg gas hobs ignite immediately but flame goes out when i let go of the igniter. I have to hold it down for a very long time befor it stays alight. this is time consuming and not right. What is the cause Thank you

I'd have a look at the thermostat. It controls the operation of the igniter. and the gas valve.

Sometimes when we clean the burners we get some debris or gunk into the gas outlets. I always take a toothpick and clean out the gas openings. Be very careful that you don't break the toothpick off in the opening. Once you've done this, use a lighter at the burner and turn on the gas. You should have a flame. Let the flame burn for about 5 minutes to burn off any more "gunk" that may be in there. Also, if your burners have covers, make sure they are in place before you light the burner.
Depending on the age of your range, you might need to clean around the igniter. Some are concealed and you can't reach them. Those that are not concealed can be cleaned by wiping with a soft, dry cloth.
I hope these suggestions help you get your range working again. If they do, please come back to Fixya and rate my advice!

Hi,

You may even see the orange "glow plug" (called a hot surface igniter) glowing orange and so assume that it's OK. Not necessarily!! You have to measure the current/amp drawn by the igniter and compare it to this repair sheet before you can say it's OK or not. The gas valve has a bi-metal that open when a certain amount of current flows through it to heat it up. The igniter is wired in series with the gas valve. As the igniter gets older or weaker, it's resistance increases to the point where not enough current is flowing to the gas valve bimetal to open it up. As a result, the gas valve never opens up. BTW, a common symptom of the early stages of this problem is erratic temperature control in the oven due to delayed firing of the bake burner while cooking.

The hot surface igniter will not come on - check igniter with a ohm meter, you should have continuity through the glow bar, the glow bar can also crack = new igniter time. The glow bar comes on but the main burner will not light - you should have an amp probe to check properly, but often this is a hot surface igniter problem. The hot surface igniter often looses it's ability to get hot enough to open the gas safety valve. The safety valve can fail, but most times it is just a bad hot surface igniter. The hot surface igniter can also quit part way through cooking , in other words the oven may cycle a couple of times and then it just sits there with the red glow from the igniter. See this service sheet for the proper way and amp readings for the hot surface igniter system. Hot surface igniters do weaken and will eventually generate less heat than they normally could. When this happens they can still allow marginally correct current to flow to the oven gas valve for it to open but not get quite hot enough to ignite the gas burner immediately. When this happens, gas released into the oven can sometimes build up to the point where when finally ignited, the amount of gas lit can cause a small explosion inside the oven or cause an odor of gas with out the oven working. Yes, your glow bar igniter can glow orange-red and still be bad!! How a common gas valve works - click here.

Let me know,if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

I would call a gas installation engineer as to me the pressure sound incorrect.
Safety is paramount with gas.

No, the igniter continues to glow. Current has to flow through the igniter to allow the main valve to open and allow the gas to flow. So the igniter will be on all the time while the broiler is operating.

Remember doing this years ago, take each gas burner on the hob apart and clean them and put them back on.

Hi, your thermocouple is faulty, it is the little probe like thingy that sticks up into the pilot flame. It is there for safety purposes, detects flame and holds a valve open magnetically to allow the gas to pass through. Try giving it a clean with a scourer, sometimes works, or your pilot flame is not big enough, could be low on gas or unit needs a service Kristian KJ Tech

Have to adjust the piolot lights for the amount of gas coming out. U have too much gas coming out(yellow flame). On older gas ranges, there was a small screw between the piolot light & burners that had to be adjusted. (if this is a older model) have to turn the screw just a little at a time, till ur flame returns to blue on ur burners. Hope this helps.

What happens in this style ignition system is that the thermostat or electronic control switches power to the oven ignitor and gas valve circuit which are connected in series (one after the other). As power flows through the ignitor it heats and draws current (measured in amperage). Once the oven ignitor draws a specific amount of current the oven valve opens to allow gas to flow to the oven burner where the glowing hot ignitor (glow bar) ignites it. Power must continually flow through the ignitor and oven gas valve for gas to be released into the oven burner to create a flame. Once the set temperature is achieved the control stops all power to the ignition circuit which causes the ignitor to dim and the oven gas valve to close, stopping any burner flame. Cycling on and off continues to maintain the specific temperature the control is set for.

A generic troubleshooting response would be...... if the burner won't stay on, either the igniter or the ignition module (or both) are bad. If the burner ignites and stays on but the spark module keeps trying to ignite, the module must be bad.