Checking the oven's gas safety valve
pilotless safety valve
used with ignitor
Their are several different gas safety valves. On ovens with ignitors, if the ignitor is weak then the oven will not light off, but what if the igniter is new and the oven will not come on?
An easy way to know for sure if that safety is bad is to see if it is open. If it has no continuity then the igniter is not going to come on.
NOTE:Never put 120 volts to the safety valve in an attempt to make it come on. All you will do is kill that valve's bi-metal. It has to be hooked in line with the igniter to work properly. Why? The ignitor takes up most of the power. The power goes through the safety valve as 120 volts but because the amperage is all being hogged by the ignitor, the gas valve opens up and allows gas to flow out into the burner and ignite. Unless it is leaking most of the time the gas safety valve is NOT the problem.
On ovens with pilot lights or standing pilots most of the time it IS the safety valve because the little thermocouple that mounts on the pilot goes bad and won't open the safety valve.
valve with
thermocouple
Flame failure device used on UK cookers
Some ovens offer a seperate safety feature called a flame switch. What it amounts to is the thermocouple mounted on the pilot light goes to the flame switch which will have continuity as long as it is heated by the pilot light.
It allows for the gas valve to let gas out as long as the pilot is lit.
flame switch
NOTE: If you do have to replace the gas valve remember this: It will not come preset. You will have to adjust the flame height with a wrench. It is a good idea to set the 2 valves side by side, adjust the orifice height on the new valve to the same height as the old one and then you need only to tweak it a tad. If the flame is too low it will take 2 hours to bake a pie shell. too high and the bottom will be cooked before the rest. It is best to adjust the flame to about half way up the flame spreader.
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