Xenon 2 leisure gas cooker After igniting the oven and small flames are seen as usual, when you shut the oven door the flames don't increase to high anymore..even though the gas knob is on full

Gas ovens / stovetop that use gas and not electricity. These work by igniting gas and use actual flame on the the stovetop.

Newest cook top styles, such as the induction or halogen cook tops combine the same style to produce more even heating. Some of these ovens feature thermal limiters or thermostats that regulate the burner system.

GAS OVENS
The spark igniter tip is dirty (can clean it with either a little wire brush or a piece of fine sandpaper).
2) The Pilot flame is too low, and the tip of the igniter is not in the flame good enough. (the flame acts as a circuit when it touches the tip & completes the circuit).
3) The spark module is no good and needs to be replaced.(But 1 & 2 are your best bet).
spark module does not sense the flame when it's on. The spark igniter is also the flame sensor which provides feedback to the spark module.

Make sure the igniter is properly aligned with the burner lighting holes and it is clean. All lighting holes must be clean too. You can enlarge them using a drill bit one size bigger.

If it would not fix the problem, replace the bake burner and the igniter.
There is a small chance for the spark module itself to be bad as well.

The oven safety valve
(also called the gas valve) is the part that ensures that gas is not released until the igniter has reached the correct temperature needed to ignite the gas. While this part can fail, it is uncommon. If the hot surface igniter does not glow you should first verify that you have voltage to the circuit. This is a live voltage check and should be performed by a qualified person. If voltage is lost at the valve terminals then you should verify the continuity of the bi-metal in the valve using a multi-meter.

when this happens it is usually because of a faulty flame/gas safety valve.

For anyone experiencing this issue, grill won't stay alight or it does but goes out after few seconds or minutes and won't stay running. this item is so overlooked however check the FSD is actually in the flame and getting hot, check your flame is consistent the same size burn across all the burner and if you changed the FSD and checked its all in order then its the grill door micro switch. yes there is a small microswitch that cuts off the circuit to the FSD and shuts gas off if the door is closed. This microswitch goes bad from the heat and causes the issue.

It could be the flame failure device our Cannon had the same problem

Most gas ovens that aren't electronic ignition usually have a pilot light.
Usually one in the oven area and one for each burner. (Sometimes shared between two burners.)
These pilot lights must lit at all times...otherwise it won't light up and you'll smell gas.
Usually the pilot light is in the very back of the oven and can be seen with the broiler drawer opened.

There is a small set screw located at the pilot light assembly in the oven and also at every burner.
This allows you to adjust pilot light up or down, thereby letting you set pilot light flame to a level that doesn't get blown out by a draft...or you can turn it off completely.

If you use that set screw to turn off the pilot light gas, you'd need to strike a match to light the oven or burners everytime you needed them.

I had a similar problem when my new Leisure cooker was installed last December. The burners would light when I held the knobs in but when I let go the flame would go out. The engineer took off each of the burner knobs and stuck a small wad of aluminium foil between the inside of the knob and the contact on the front of the cooker - he said it's a design fault and the gap is just a bit too large for contact to be made reliably. This fixed the problem and I've had no trouble since.

Hi

If it won’t fire then it is possible that the oven control is not sending gas for the pilot light. The pilot light works but no main burner ignition - possible pilot assembly is dirty and the pilot flame is too small, safety valve and thermocouple is faulty, the bulb from the safety valve is out of position and the pilot flame is not touching the thermocouple bulb. Some ranges use a standing pilot light ( small flame is on all the time ) while others use an spark ignition to light the pilot light flame and the pilot light flame heats up the thermocouple bulb to allow the main gas to flow through the oven burner.
The flame needs to heat the bulb up enough to tell it to open the gas valve. Several things can go wrong here that keep this from happening:
The pilot flame may not be hot enough, usually because the flame is yellow instead of pure blue or is too small. The cause for this is usually a dirty pilot assembly. The pilot assembly would either need to be cleaned or replaced.
The thermocouple bulb may not be positioned properly in the flame. You can't heat the bulb properly if it's not in the pilot flame! The thermocouple bulb needs to be in the upper third of a pure blue pilot flame--that's the hottest part of the flame.
The thermocouple itself may be burned out. It happens. It's an internal part of the gas valve so, no, you can't just change the thermocouple bulb separate from the gas valve.
But when you turn on the oven or the thermostat calls for heat, the pilot flame gets bigger and jumps down so it can heat up the thermocouple bulb. This extra gas to increase the pilot flame size comes from the thermostat.
If the pilot flame jumps upwards or just gets bigger, but doesn't shoot down, then you need to replace the pilot assembly.
If the pilot flame size does not increase or jump down when turning on the oven thermostat, then the problem is the thermostat not sending enough gas to the pilot assembly. It's also possible that the pilot gas supply tube has a hole in it somewhere.
One final point on the spark-assisted pilot ignition systems. The spark comes from the spark module--the same module that sends spark to your surface burners to light them up. If you're not getting a spark when you turn the oven on, then there are several possibilities:
There could be a problem with the switch in the thermostat. You can confirm this by doing a simple continuity test of the thermostat contacts. If you don't read zero ohms when you turn the switch on, replace the thermostat.
The spark module could be bad. You'll need to measure the voltage at the oven terminals of the spark module when you turn on the oven. If you get 120v but no spark, it's probably a bad spark module. Replace it.
Could be a bad spark wire or broken electrode.

Please do rate the solution and revert for further assistance.


Thanks
Rylee

all gas range ovens have a small metal box in the back upper area of the broiler burner; a gas line runs into this box as do two wires; this is a "flame control " gas valve; the way it works is: after the pilot has been lit as you turn the oven temp control a heating element in the box causes a small valve to open allowing a larger amount of gas into the oven burner to ignite the whole burner If you can only get pilot flame on high replace this valve

Our oven had the same fault.

It turns out that the air intake was blocked.

The air intake is at the front, just below the bottom oven door. Some liberal sucking with a hoover sorted the problem instantly.

It sounds exactly the same as I am experiencing on my oven of the same model. My theory is that the full flame gas is controlled by a thermostat, and that this has broken hence why the oven only stays on preheat. This will be a matter of a replacement part. Most likely the thermostat is a bi-metal strip that, because it has heated and cooled so many times in it's life it has simply finally given up. Try searching online for the correct part and get a corgi registered fitter or another suitably qualified fitter to come and replace it.