# Pilot goes out



## FanMan (Oct 18, 2012)

I have an Osburn LA30 gas stove.  Lately the pilot goes out intermittently.  It lights fine, and stays lit, then some time later I notice that it's gone out.  It always relights just fine, and the main burner ignites when the thermostat calls for heat... if the pilot is still burning.

When the main burner shuts off, there is a momentary flickering of flame, then there's always a final "POOF".  Every time I check the pilot right after that it's still burning, but that doesn't mean the poof _doesn't_ blow it out occasionally.   

I did recently add a second [used] propane tank so I might suspect some air in the lines, but the main burner has been run long enough that I would think any air would be purged out by now.

The pilot flame looks like it's large enough, and properly impinging on the thermocouple and thermopile.  To be sure, I cleaned it tonight, but I don't see any difference.  Hasn't gone out yet but that doesn't mean anything.

It doesn't happen just on windy days so I doubt it's a draft issue.


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## DAKSY (Oct 19, 2012)

Is the top 3/8" of the thermocouple engulfed in the pilot flame? If you have a multimeter you can check to see what kind of millivolts it's generating when under flame...If the mV reading is lower than 28, it may be time to replace it, but I'd look to see if there's a pilot adjustment screw on the gas valve & maybe you can crank it up a little...It's also important to also read the mV output of the thermopile with the burner off. Generally, a tp will fail at 750mV, & I like to keep them set at 550 +/- 25 mV, so you don't want to increase the pilot too much...


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## FanMan (Oct 19, 2012)

I haven't checked the voltage yet, didn't know what it should be.  But I'm not clear on what you mean; the tp output should be 550 but could be as low as 28?  The pilot adjustment was all the way up already, the pilot flame does cover about 3/8" of the thermopile but not necessarily all the way round it.  On the opposite side and in the flame there's another probe in the flame (not the ignitor); is that a separate thermocouple for the pilot safety or something else?


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## DAKSY (Oct 19, 2012)

FanMan said:


> I haven't checked the voltage yet, didn't know what it should be. But I'm not clear on what you mean; the tp output should be 550
> 
> *Yes the thermopile (tp) output should be around 550 mV, if you can get it there, sometimes output as low as 480 mV isn't a problem. At about 325 mV it'll shut the burner down...*
> 
> ...


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## FanMan (Oct 19, 2012)

OK, gotcha.  That's what I thought.  Sounds like possibly a thermocouple problem then, since it's the pilot I'm having trouble with, not the main burner.  Only hitch is the parts list doesn't call them out separately; it appears only the entire pilot assembly is stocked ($$).  But I'm an engineer, used to design gas stoves for a living and am quite familiar with industrial and aviation thermocouples so I can no doubt work something out... do you happen to know if it's a type J or K thermocouple?


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## DAKSY (Oct 19, 2012)

FanMan said:


> OK, gotcha. That's what I thought. Sounds like possibly a thermocouple problem then, since it's the pilot I'm having trouble with, not the main burner. Only hitch is the parts list doesn't call them out separately; it appears only the entire pilot assembly is stocked ($$). But I'm an engineer, used to design gas stoves for a living and am quite familiar with industrial and aviation thermocouples so I can no doubt work something out... do you happen to know if it's a type J or K thermocouple?


 
Sorry, I don't know which one it is, maybe it's listed in your manual...If you take it to a local hearth shop they should be able to match it.


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## Heatsource (Oct 20, 2012)

here is a nova sit guide i uploaded a few years ago, i'm pretty sure thats the valve in use...

also, have you checked out the venting? is at least the flue collar and cap sealed w/milpac?


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## FanMan (Oct 20, 2012)

Thanks Dave, that looks like the same valve.

Venting should be OK as I didn't have any trouble with it last year.  At the moment it seems to be OK so cleaning it may have done the trick, though it's been warm enough that the main burner hasn't switched on.  Supposed to get colder tonight so we'll see...


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## FanMan (Nov 8, 2012)

Update:  Still working, even through the winds of hurricane Sandy and last night's Nor'easter, so it was either cleaning the pilot (I couldn't get it out so I sprayed automotive mass airflow sensor cleaner through it) or air in the lines finally working out.


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