# Pilot flame...too big?



## timcoon (Apr 15, 2009)

Hi All,
I have been struggling with my Bryant 394GAW furnace (20+ years old) over the last couple of days. Pilot would light ok and then burners would light ok, but then they would go out after ten seconds or so. That would repeat a time or two until the blower would finally come on. After much online searching, I ended up cleaning and sanding the flame-sensing pilot assembly as well as the pilot gas tube. Seems to be working much better now, but the pilot flame itself is now MUCH bigger than it was before.

Before the cleaning it was maybe a one-inch, easy-going flame, all nice and blue like it's supposed to be. After the cleaning, it's still nice and blue, but is now at least three-inches long and a little more jet-like. Is this normal for this type of furnace? Again, the sequence of operations seems to be fine, and everything is working better than before.

I am fairly certain that I didn't inadvertantly adjust or change anything else...just the cleaning.

Thanks for any input.

Tim


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## hvaclover (Oct 2, 2008)

You either dropped the pilot orifice or enlarged the orifice opening.


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## beenthere (Oct 11, 2008)

You did something.


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## timcoon (Apr 15, 2009)

I know that I "did something," I just don't know if I did something wrong, or simply cleaned out a dirty orifice and the flame is now the way it should be.

Is there a "right" size for the pilot flame? There is actually some discoloration on the wall of the heat exchanger, adjacent to the pilot, as if the pilot flame used to be this way.

I guess I am wondering...is it wrong? And if so, can I adjust something like that somehow? Can I "raise" the orifice if I dropped it? Or do I need to replace the pilot/ignitor assembly?

Thanks again.


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## beenthere (Oct 11, 2008)

Did you put the orfice in upside down.

You can adjust the amount of gas going ot it.
But first, you have to see if you did anything to the pilot that needs corrected first.
Did you ream the orfice out.


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## hvaclover (Oct 2, 2008)

If you reamed that orifice too large than adjusting the pilot press is not going to cure your problem,

Too big an orifice with too little gas is gonna make a dirty flame.


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## timcoon (Apr 15, 2009)

I never even took the orifice itself out of the assembly, so I know it is not upside down. I did use a straight pin to try and clean out the orifice, although "reaming" would be a pretty strong word for what I did. I basically just stuck the pinhead in there and twisted it a little bit to clean the hole. The pin would not go throught the hole, and I didn't force it, but I used a wee bit of pressure just to clean out any scuzz. Are they THAT precise?


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## beenthere (Oct 11, 2008)

Yes they are.


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## timcoon (Apr 15, 2009)

Maybe I put too much into the cleaning. Would you say that if I can get a nice soft blue flame by reducing the gas a bit, that would be okay? I would rather not replace it if I don't have to, but I will if that's the only way.

Are you familiar with the ignitor/pilot assembly I am talking about? Is there a guideline for how high the pilot flame should be?

Thanks for all your help,
Tim


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## beenthere (Oct 11, 2008)

The pilot flame should engulf the top 1/3 of the thermocouple only.

You need a new orfice.

If you lower the gas down, you won't get a good air mix.


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## timcoon (Apr 15, 2009)

There really isn't a thermocouple with this one, just the pilot assembly and the ignitor, so i'm not quite sure how big the perfect flame is.

It doesn't really matter, it's clear there's something wrong, I am going to go ahead and replace the assembly. It isn't worth the aggravation or the worry - bloody thing's over 20 years old anyway, it deserves a new part every now and then.

Thanks for your help!


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## timcoon (Apr 15, 2009)

beenthere, would you say this is a big safety issue, if it operates like this for a few days, until my new parts arrive? As I said, everything appears to be working correctly, if not better than before - the sequence is all correct, no false burner starts, etc. - there's just the large pilot flame.

Thanks


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## beenthere (Oct 11, 2008)

More of a waste of gas.

Has the potential to produce some excess CO. 

Dangerous if it were to go out for some unknown reason and putting in all that excess gas, which won't always vent up the chimney.


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## kenmac (Feb 26, 2009)

Wonder if he has that old bryant 3 wire pilot assy ??


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## timcoon (Apr 15, 2009)

kenmac,

Yup, it's the old 3-wire pilot assembly.


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## beenthere (Oct 11, 2008)

G6 pilot assmbly, I think.


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## kenmac (Feb 26, 2009)

Can't picture the 1 you are talking about.. This is the 1 I was thinking of


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## beenthere (Oct 11, 2008)

I'm thinking of an older one yet.

Just showing my age a little I guess. oops. LOL


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## hvaclover (Oct 2, 2008)

kenmac said:


> Can't picture the 1 you are talking about.. This is the 1 I was thinking of



If it's spark then that's the one.

Only other kind was a two wire assy


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## timcoon (Apr 15, 2009)

That's the one. In fact, that picture is from the website where I ordered my replacement.


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## kenmac (Feb 26, 2009)

I think That one had a small coil that heats up red hot to light pilot & some had a spark..can't remember which had wihich haven't seen these in a while. For some reason, I still carry 1 on my truck .Old bi metal stuff.. You can probably re- use your old pilot tubing


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## timcoon (Apr 15, 2009)

Thanks, kenmac. Mine has the spark ignitor, which I also got a replacement for. I'm sure that would go next, so I figured better have it just in case.

I guess I should consider myself lucky, this thing has been running like a trooper for quite a while now. We just started the "furnace replacement fund"...I hope it's "funded" before I need it!


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## yuri (Nov 29, 2008)

Make sure you have 2 newer good quality CO detectors in your house. One near your bedroom and the other in the furnace room or stairwell leading upstairs. Heat exchangers can crack at any time after 20 yrs or sooner for some brands.


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## hvaclover (Oct 2, 2008)

hvaclover said:


> If it's spark then that's the one.
> 
> Only other kind was a two wire assy



HEY PROS!Just curious how you troubleshoot this assy to make sure its not the valve.

I use my volt meter plugged into the pilot and main burner receptacle in the assy wire harness and let the pilot burn long enough 'til the bi metal either drops out of main burner. I f it does not drop main burner after twenty minutes I call it the pilot assy..

How about you guys?


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## kenmac (Feb 26, 2009)

hvaclover said:


> HEY PROS!Just curious how you troubleshoot this assy to make sure its not the valve.
> 
> I use my volt meter plugged into the pilot and main burner receptacle in the assy wire harness and let the pilot burn long enough 'til the bi metal either drops out of main burner. I f it does not drop main burner after twenty minutes I call it the valve.
> 
> How about you guys?


 
I'am by far a ''PRO'' But, I'll give it a shot.....I would un plug the pilot, connect my meter to the bi metal connection wire & what would be the Power wire. set to ohms scale. If bi metal has made up it should show contiuity between the voltage wire & what I would call the common wire or bi metal wire...I say it's the valve

Provided ,I have correct voltage in the correct placed


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