Glowing Flue Pipe

[Jodi]

A few nights ago, I loaded up my insert and let it run with full air for a little while to get it up to temperature. The temperature was at approx. 480 F and then I realize that the stainless steel flue is glowing red from just above the adaptor to the block-off plate. The flames were pouring over the baffle and I guess were being sucked up the flue. I turned the air all the way down, and after a little while, the pipe stopped glowing, but it was a scarey situation. After the air was turned down, the temperature only increased to 530 F. I confirmed this with a second magnetic temperature gauge.

I have a 6-inch M-Flex stainless steel liner (0.006) from the top of the insert to the top of the chimney (18'). The insert is in a corner masonary fireplace. So the stainless steel flue goes through a slight incline for about 5 feet through 11" X 11" terra cotta, and then when it gets to the exterior chimney it goes straight up through 11" X 11" terra cotta lined chimney. My stainless steel liner is uninsulated, but I have a top stainless steel plate with 5-inches of ceramic fiber insulation under it, and I have a block-off plate above the insert with 5-inches of ceramic fiber insulation on top of the block-off plate.

Now the flue has a brass color between the insert and the block-off plate. The heat output of this insert has been disappointing as the insert has never gotten above 530 F even though I have tried various air settings and different wood from friends. Even when the flue was glowing the heat coming off the insert was minimal.

My insert always gets a good fire going, and when I turn the air down, I get a good secondary burn, but the heat output is poor. What is the problem? Is it possible that I have too much draft?

 

[Todd]

Have you checked all your gaskets? I think the baffle has a gasket? Sounds like all the heat is going up the flue. Do you have a blower, I think it's a must for inserts.

 

[Jodi]

Yes, the baffle gasket is new, and I have a blower. I was thinking that I am losing heat up the chimney, but if that is the case, how can I resolve this issue?

 

[Hogwildz]

At 530 try shutting the air down all the way to low, temp should rise to 600 or more easily. If it doesn't. there is something wrong.
You did knock out the knock out plate on the left casing? If your getting good secondary, there is no way you shouldn't be getting decent heat from it.
My insert even at 800+ doesn't make the liner glow. Where are you taking temps from? What kind of wood are you burning? How much are you loading?

 

[Jodi]

I shut the air down all the way once it gets up to temperature, and still never can get it above 530 F. I am taking the temps. from the right front above the door. I burn oak and can always get a good fire and secondary burn, but the heat output is poor.

I typically put in about 6 good size splits, and the flue pipe never glowed until a few days ago.

 

[Jodi]

Also, I did remove the knock out on the left side.

 

[Jimbob]

Does the fire look like this while it is going?

 

[Jodi]

No, I have more flames even when it is turned all the way down.

 

[Hogwildz]

I suggest checking the door adjustment. Do the dollar bill test on the door.
You should not have a flaming fireball very long after shutting air back.

 

[Jodi]

Just did the dollar bill test and the top and bottom are very tight, but on the left and right sides of the door, I can wiggle the dollar bill out fairly easily.

 

[Hogwildz]

Thats strange. Should be tighter as you go closer to the hinge side.
How loose is loose? Is there any resistance? With the bill stationary, can you wiggle it back and forth very easily?

 

[Jodi]

On both sides of the door, I can wiggle it back and forth fairly easy and pull the dollar bill out. On the top and bottom, I can't move the dollar bill at all.

 

[Todd]

Sounds like you need to adjust your door for a tighter seal. Does you manual tell you how to do this?

 

[crazy_dan]

I think I would have the dealer come over and look at it as it should not be loose on the hinge side sounds like a warped or bowed door.
because beating on the hinges is not my picture of a good idea.

 

[webbie]

Being able to wiggle that bill out does not sound like a lot of air entering. Still, no harm in tightening it up. It just might be that you have the Florida Bungalow Syndrome, and I guess there may be some way to adjust the incoming air - primary or secondary. Check with your dealer or PE about this.

 

[Jodi]

Thanks for all of the input. Ok, if it is too much draft, is there anything I can do other than adjusting the incoming air? I really need to straighten this out very soon.

 

[crazy_dan]

Damper in the flue pipe is probably the easiest way.