My rangemaster cooker lights on ignition but only stays on low flame is it the thermostat or safety device

It's a safety feature that it goes out but this situation is dangerous. Do a normal cooker cleaning and see if that helps. Otherwise you must call a gas engineer.

Hello Saidie,

It is a common problem, but the first time I saw it, I thought it was the thermostat. But it is not.
It is the flame safety device that needs to be changed. You can not repair them, it has to be replaced by a good one.
Link one gives you picture of the complete burner unit
https://shop.ukwhitegoods.co.uk/012503000-flame-failure-device

link 2 gives an example of the single unit.

Flavel Leisure Cooker Spare Flame Failure Device FFD CO1464


I wish you succes, Dik

Hello,

it is always terrible when items does not work as it should.
I expect that this cooker has flame safety.
The first thing I suspect, is your FFD (=flam failure device). Besides the burner are 2 points, one is for the spark, the other is the sensor for the safety device. On that point is connected a thin copper "wire" that goes to the tap. There it is screwed in.
The test is, stays the burner on when you keep the button pressed in. If that is the case, and the burner goes out after letting go the button, then I am sure it is the FFD.

I hope this helps, Kin regards, Dik

common problem, there is a device in the oven called a solenoid/ff device these are safety devices and fail after a few years. replacements can be obtained from main stockist Gas On spares on 0121-585-7799

the flame safety device need replacing (FFD)... this lets the full gas through when flame is sensed... safety 1st as a gas engineer will be required..

the part that you need is the oven ignitor, located nest to the oven burner. that part gets hot to open the gas to the burner, that will make the oven work again.

Its the flame failure device faulty (FFD)

The knob won't have any effect on the flame size.  The knob controls temperature.  If you're referring to the pilot light staying on and then the main flame not going on...that's another problem.  If the main flame will not go on, the assembly that controls the main flame is likely defective.  If the unit has a thermocouple, you might change it out first.  Sometimes, that's all that is needed and they're cheap.

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.

some older ovens did use one side just as a "bread warmer"...only way to tell for sure is to check if there is a burner below the left side