Jotul Natural Gas Stove Won't Light - Pilot Runs Fine - Voltage/switch seems fine - What next?

[tembenite]

Hello,
I'm hoping someone can help.

I've got a Jotul free standing gas stove that came with the house I bought four years ago. It has run fine for the 3-4 seasons I've owned it, but this season the pilot stays on, but it will not lite (The knob is set to "On", the switch is also set to "On", and the dial is set to "high"). I do not know the year, or the exact model. It looks very similar to the GF 400 or GF 600 series.

Based on some other posts I found with similar problems, I got out my multimeter and confirmed that I have voltage at the On/Off/Stat switch, and where the external thermostat would hook up on the lower left part of the stove, where the pilot/on/off knob is and the low/high dial. I've tried jumping the connections in both places, and it still won't light. However, when I jump it I do hear a slight clicking noise, as if something is engaging somewhere.

At this point I'm completely at a loss as to what to try next, and its getting pretty cold up here in upstate NY. Unfortunately due to some renovations our regular oil furnace is presently disconnected, we'd been kind of hoping the gas stove would get us through the fall while I finish working on things. Figures this would be the year it didn't light .

Any ideas of what the next steps are to troubleshoot, or what the problem may be?

Thanks-you for your help!

Doug

 

[DAKSY]

Test your thermopile at the TP & TH-TP (or TP-TH) connections on the terminal block
located at one end of the gas valve.
Set your multimeter to Mv (Millivolts) & make contact with the screw heads.
With the switch in the off position, you will be reading the Mv generated by the pilot flame
on the thermopile...you wanna be about 550 millivolts.
If you don't get that your t-p is probably bad.
Check it & let us know what you get...

 

[tembenite]

ok, if I'm using my multimeter correctly, and its supposed to be "550" millivolts, that looks like it is the problem.

Just to verify since I haven't used this that much... I've got this multi-meter:
http://www.garage-jdm.com/garagesale/electrictools7.jpg

I have the black wire in the "com" port, and the red wire in the "V" port, like the picture.

When I turn the dial to the black V section under, 2, 20, or 200, the digital reader reads about .220 (Which I think means 220 millivolts).

Is there any safe way to "jump start" the stove while I order a part (I'm assuming this isn't something I can find in stock locally, but I could be wrong).

Thanks for your help!

 

[tembenite]

Ok, I just reread your post and noted that I hadn't made sure that the switch was in the "off" position when I took the multimeter reading.

When I make sure the switch is off the reading is:
.517

Is that close enough to "550 millivolts" to not be an issue, or is that still too low?

Thanks again for your help! It is VERY much appreciated.

 

[DAKSY]

517 is ok & it should light. Take another reading & see what the Mv
reading does when you turn the burner on. It should drop about 200 Mv.
Did you have the pilot off all summer?

PS. Where you at in Upstate?

 

[tembenite]

Yes, I had the pilot off all summer.

When I turn the switch to "On", the voltage drops to ~210.

 

[DAKSY]

Ah hah! That drop tells you that the gas valve has opened & the gas is flowing thru it.
You're gonna hafta pull the burner. Once you get it out, Get yourself a 1/2" or 13mm
box wrench or socket & remove the burner orifice...
Stick a pipe cleaner or Q-tip into the gas tube behind that orifice &
I bet you dollars to donuts you're gonna find a spider web back there.
Once you clear it & reassemble you should be good to go...

 

[tembenite]

Arg... pesky spiders! That seems a very reasonable conclusion too.

I've turned off the pilot, and when it cools down I'll give it a shot sometime tomorrow.

Again, thanks again for all of your help! I'll let you know how it goes!

 

[tembenite]

Well, I took everything apart and got down to the burner orifice.

There were a decent amount of cob webs throughout the stove, so I thought there was a very good chance that this must be it. However, when I actually took off the burner orifice, it looked completely clear.

I cleaned it just the same, figuring that maybe I either didn't see something or I dislodged something in the process of taking everything apart. I also cleaned the cobwebs out of the rest of the stove, so now it looks nice and clean.

I then put things back together, let it sit for a few minutes with the pilot lite on, and then flipped the switch to "on". Unfortunately :-(, its still not working.

I guess this means there is either a clog somehow in the line that runs to the burner orifice, or there is a problem with the actual valve? This doesn't seem to make too much sense.

I think I'm going to go back and double-check what I've done. Let me know if you can think of anything else to try.

Thanks again for all your help!

 

[tembenite]

Hmm... I just thought of something.

When I put things back together, there was a lot of different ways to position the air shutter. I wonder if I simply didn't configure that right. I'm going to go back and play around with that.

 

[heat seeker]

The valve might be stuck. A few gentle taps on it might awaken it, while energized.

 

[tembenite]

The valve might be stuck. A few gentle taps on it might awaken it, while energized.

I gave that a try, but no luck :-(.

FYI, in poking around the Jotul manual's it looks like I have a GF600. The GF400 is actually laid out a little differently.

The only thing I can think of right now is that the valve assembly must have somehow gone bad. That seems extremely unlikely to me, but its about all that is left.

I suppose I might try taking off the tubing that goes from the valve assembly to the burner, and just see if there are any types of obstructions. I don't know how something would happen over the seasons to that, but it seems like all the logical conclusions are taken. I was really thinking it was going to be a pesky spider.

Has anyone ever seen the valve assembly in a Jotul go bad?

 

[DAKSY]

You said in a previous post that the millivolts dropped when you
turned the unit on. That, to me, indicates that the valve is working correctly.
The millivolt drop means the electromagnets controlling the gas flow to the
burner were getting charged & opening. It's either a blockage in the gas line
or the regulator is stuck. I'd rap the regulator head with the plastic handle
of a screwdriver...
Did you check the burner orifice for obstructions?

One other thing to try...Jump the TH & TH-TP terminals to rule out the switch.
It shouldn't work, but hey...

 

[tembenite]

Yeah, I checked for burner orifice obstructions. I took the whole burner orifice off with a 13mm wrench, per your instructions.

There was nothing visible blocking it, but I ran the tip of a small cloth through both ends a few times, and blew through hard a few times. When I was done I held it up to the light and looked through it, just to be absolutely sure I couldn't see any obstruction. It looked perfectly clear. I didn't have a pipe cleaner to run through it, but I'm pretty confident I would have seen something if it was in the way.

By the "regulator head", do you mean what the gas line attaches to when it runs from the valve unit (with the Pilot/On Knob, and high/low dial), over to the burning orifice?

If so, that's exactly what I did when "heat seeker" recommended I give it a good tap.

As for your latest suggestion on jumping from the Th/TH-TP, I had tried that yesterday, but hadn't done it again today. I'll give that a shot. Maybe my switch is bad AND there was a blockage that I happened to clear out today.

 

[North of 60]

Are you talking about the same gas orfice. You mentioned a pipecleaner. The orfice diameter is quite smaller.

 

[DAKSY]

I just re-read this whole scenario & realized that you never
mentioned (or maybe I missed where you DID) running a pipe
cleaner into the gas tube BEHIND the burner orifice.
THAT'S usually where them damned spider nests are...