Glow-bar ignition system troubleshooting & repair
The symptom, of course, is that the oven burner won’t ignite. As always, first check the automatic bake cycle (timer) controls, if any.
Aside from the thermostat and other safety controls, there really are only two parts to the glow-bar ignition system; the ignitor and the safety valve. (Figure 6-L)
Figure 6-L: Typical Gas Oven Ignitor System
There may be a fuse as well. Usually the fuse is located down near the safety valve, but in some installations it’s under the cooktop or inside the console. If you have a system with a fuse, check that first for continuity.
Typically it’s the ignitor that fails, and when it does, you can usually see the damage to the element inside the cage.
However, this is not always true. If the ignitor gets old and weak, it will still glow, but usually only red- or orange-hot, not yellow-hot. When this happens, the resistance is still too high for the safety valve to open. It can throw you; since you see the ignitor working, you think the problem is the safety valve. It’s usually not. And electrical parts are non-returnable.
When diagnosing these systems, I recommend replacing the ignitor first. If the problem turns out to be the gas valve, you just ate an ignitor, but trust me, you’d have needed one sooner or later anyway.
It is very important to make sure you get the right ignitor and/or gas valve for your oven. The safety valves are matched to the ignitor, and the ignitor is matched to the burner.