Thor gas oven & broiler won't light

[dungears]

I have a Thor 36 inch Pro-style 6 Burner Gas Range. It's setup to use propane. It's about 3 years old.  Both the oven and broiler no longer light. Both stopped working at the same time. Both igniters glow when they are turned on. If either one or the other had stopped lighting I would have figured it was the igniter, but since both stopped working at the same time I'm thinking it's something else. Also, I changed the oven igniter a couple months ago so it's unlikely that's the issue (but i guess still possible).

Anyone got any ideas? Thanks.

[MarcusF]

Best thing you can do is check the current draw of the igniters with an amp clamp. They're connected in series with the gas valve, and need to draw a certain amount of current in order for the gas valve to open up and let gas through. The current draw the gas valve needs in order to open is usually written on a sticker on the gas valve itself, and most often it's a range between 3.3-3.6A. 

[dungears]

The current was ~2.85A.  So I'm guessing one or both of the igniters are no good.  They are connected in series, so I'm not sure how I can test which is bad. 

I know next to nothing about electricity, so this may be a stupid question...  Can I connect the safety valve to one igniter at a time and check both independently?  Or is connecting one at a time going to break something?

Thanks.

[dungears]

My previous post said I checked current and found it to be at ~2.85A.  This was tested right at the safety valve, and tested with the oven on. 

After that post I ran another test.  I tested the current again right at the safety valve with the broiler turned on.  The current was zero.  Which seems odd since the broiler igniter is glowing.

[daveca]

I'm an engineer (and former TV/ appliance tech) who just diagnosed and changed one of these hot surface devices. Thor LRG3601U.

The defective igniter can be seen to only have two of the four lines glowing, the center two. Slow to start, weak orange- red glow. Compared it to the broil igniter, it was orange- yellow.

The current on a current clamp meter on one wire ( cant clamp both,,!) was 1.54 A AC. Way low. Valve says "3.3-3.6A"

Oven light- off was intermittent and getting worse. Took 5-10 minutes to start 

Gas pressure, 8.45 IWC. Good.

The igniter failure is that the element cracks and gets thin near where it exits the ceramic block. I removed it, and gently pulled straight out on the element to see if it unplugged. Thats where its bonded into the ceramic block and has a lot of mechanical stress when it heats and cools.

It broke off instantly.

So I took the igniter from the broil element assembly and put it in the bake position.  We never use broil. Fixed. Happy wife, happy life.

Removal, remove the access panel in the right rear of the oven cavity bottom ( one screw), remove the three screws holding the oven burner assembly to the floor, disconnect the 1/4 inch spade terminals on the igniter and push them into the oven cavity, then lift the burner and igniter out as an assembly.

One screw holding the igniter assembly had to be cut out with a Dremel tool. The heat charred the threads.