The burner in our oven failed in December 2006, probably because the charred remains of an insect produced a hotspot:
That replacement burner came with its own igniter that failed after 8.5 years, with symptoms of slow oven ignition and the occasional smell of propane.
In normal operation, the igniter element glows yellow-hot for a minute or so before the valve opens, gas flows over the igniter, there’s a muffled whoomf, and the oven begins heating. The igniter remains powered as long as the oven is on, emitting a baleful yellow glare through the slots in the oven’s lower cover.
It consists of a ceramic base holding a stout resistance heater that apparently suffers from increasing resistance as it ages, reducing the current to the point where it won’t activate the gas valve.
I didn’t know that, either, but Google sees all, knows all, and tells most.
The gas valve label says it requires 3.3 to 3.6 A from the heater to turn on the gas:
But the old heater was good for barely 2.6 A (there’s a bit of parallax in this view):
Igniters range from $18 to upwards of $60 on Amazon, so I picked the cheapest one, waited two days, installed it, and measured 3.5 A at First Light, down to a bit over 3.0 A at running temperature. That’s on the low side of the valve’s spec, but it seems happier with an extra half amp.
We’ll see how long this igniter lasts; maybe next time I’ll double my spend…