Vermont Casting Defiant Encore 2190 -- over-firing ???

[cwitz]

A bit of a long story, but here goes:

We have been living with a VC Defiant Encore 2140 for 12 years -- I think I understand it pretty well. We burn about 3 cords a year of dry beech/oak/maple mix in it. Typically, we get it going w/ a full load of wood, and with the main damper closed and the thermostat in its most closed position, a surface thermometer placed on the top (and a bit to the side) reads in the 500-600 degree ranges. Once it's going, it can't be brought below this level.

That stove is getting old -- lots of crazing in the enamel, and now a small crack in the cast iron top. So, we found a used 2190 in decent shape. When I first fired it, it over-fired, getting up around 800 degrees. The ash pad door was not sealing well so I replace it. This help some, but not enough.

We brought it to a stove shop and explained the problem. He replace a few more gaskets, notably the main damper gasket, and pronounced the stove fit. He found the catalytic converter to be in good order.

It is now back in service but it runs about 100 degrees hotter than the old 2140: with a full load of wood it will run up into the 650-750 degree range and I cannot keep it lower than that. The interior cast iron hood over the intake to the catalytic converter glows a bit red, but no part of the exterior glows, and the vent pipe runs 450-500.

I was suspecting intake air leaks, but the stove shop owner says no. He asserted that the intake flap was closing properly and that he had tested it for leaks by sealing the flue and burning some paper inside -- no smoke escaped.

IS THIS STOVE OVER-FIRING? SHOULD I BE CONCERNED?

I'm tempted to look for leaks in the part of the ash pan that's bolted to the bottom of the stove, but that starts to get involved...

 

[webby3650]

Hi, and welcome. Are the temps on the new stove with the primary air on high, or low? 750 is a little high, it won't shock me if it spiked here, but it should calm down after a short time. It's normal for the throat piece to glow a little, you just don't want to happen for long periods of time. And nothing on the exterior should glow. Have you done a dollar bill test on the doors yet? Give that a shot.

 

[BrowningBAR]

A bit of a long story, but here goes:

We have been living with a VC Defiant Encore 2140 for 12 years -- I think I understand it pretty well. We burn about 3 cords a year of dry beech/oak/maple mix in it. Typically, we get it going w/ a full load of wood, and with the main damper closed and the thermostat in its most closed position, a surface thermometer placed on the top (and a bit to the side) reads in the 500-600 degree ranges. Once it's going, it can't be brought below this level.

That stove is getting old -- lots of crazing in the enamel, and now a small crack in the cast iron top. So, we found a used 2190 in decent shape. When I first fired it, it over-fired, getting up around 800 degrees. The ash pad door was not sealing well so I replace it. This help some, but not enough.

We brought it to a stove shop and explained the problem. He replace a few more gaskets, notably the main damper gasket, and pronounced the stove fit. He found the catalytic converter to be in good order.

It is now back in service but it runs about 100 degrees hotter than the old 2140: with a full load of wood it will run up into the 650-750 degree range and I cannot keep it lower than that. The interior cast iron hood over the intake to the catalytic converter glows a bit red, but no part of the exterior glows, and the vent pipe runs 450-500.

I was suspecting intake air leaks, but the stove shop owner says no. He asserted that the intake flap was closing properly and that he had tested it for leaks by sealing the flue and burning some paper inside -- no smoke escaped.

IS THIS STOVE OVER-FIRING? SHOULD I BE CONCERNED?

I'm tempted to look for leaks in the part of the ash pan that's bolted to the bottom of the stove, but that starts to get involved...

650-700 is the upper level of my comfort zone. 450-500 vent pipe temps is warmer than my pipe gets on the Encore (250-350 is what I usually see, even when running hot). When running hot temps with the Encore I like to keep it at 650. Sometimes it creeps up to 700 on me, but not often.

The Defiant likes to creep beyond 700 on me when the air is closed off. A solution is some aluminium foil and a few magnets to partially cover the primary air in the back of the stove. It will take the temps back down to levels that you are comfortable with. This will also work with the Encore.

 

[cwitz]

Hi, and welcome. Are the temps on the new stove with the primary air on high, or low? 750 is a little high, it won't shock me if it spiked here, but it should calm down after a short time. It's normal for the throat piece to glow a little, you just don't want to happen for long periods of time. And nothing on the exterior should glow. Have you done a dollar bill test on the doors yet? Give that a shot.

These temps are w/ everything as shut down as I can make it: the main damper (left side lever) is back and latched; primary air lever (right side) fully back position (and I can hear the flap underneath at the back click shut); and the damper in the flue pipe which I usually use when there a wind outside that boosts the chimney draft is also closed down. 750 seems to be the high end of things -- doesn't stay there long -- but I'm concerned that it gets up there in the first place.

My impression from my experience w/ my old 2140 is that I should be able to bring it down to 550 by shutting off the primary air, but the 2190 seems to run hotter.

When I checked out the stove originally I did the dollar bill test and it seemed to seal. The stove shop went ahead and replaced the door seals anyway -- I'm skeptical that it needed it. All he did was replace some gaskets, which is not what I really wanted. I was hoping he'd go at it a bit more analytically, but no such luck.

My question really is this: between what I did and what the stove shop did, I believe all the gaskets are good and that the primary air closes off properly when the lever is back and the stove is up to operating temp. Are the temps I'm seeing normal or should I be looking for more subtle leaks, and if so, what should I be looking for?

 

[cwitz]

650-700 is the upper level of my comfort zone. 450-500 vent pipe temps is warmer than my pipe gets on the Encore (250-350 is what I usually see, even when running hot). When running hot temps with the Encore I like to keep it at 650. Sometimes it creeps up to 700 on me, but not often.

The Defiant likes to creep beyond 700 on me when the air is closed off. A solution is some aluminium foil and a few magnets to partially cover the primary air in the back of the stove. It will take the temps back down to levels that you are comfortable with. This will also work with the Encore.

I'm not sure I understand what you're suggesting with the foil-and-magnets. Are you putting it over part of the opening so that even when the primary air is open it's pulling less air? I assume you leave it there all the time (wouldn't want to be reaching back there when the stove is running).

I would have though that by design when the flap closes it would cut off all air and the stove temp would come down -- that's how thermostats should work.

I'm concerned that even when that's happening I'm getting air in somewhere else that makes it hard to control. But where might that 'somewhere else' be??

 

[BrowningBAR]

I'm not sure I understand what you're suggesting with the foil-and-magnets. Are you putting it over part of the opening so that even when the primary air is open it's pulling less air? I assume you leave it there all the time (wouldn't want to be reaching back there when the stove is running).

I have a rectangular piece of aluminium foil that is attached by two magnets on the left side of the primary air opening. The rectangular piece of aluminium foil is pulled open to the left. When I need it closed due to excess stove temps of strong draft, I pull the foil across the primary air and attach a third magnet to the top right to minimize air flow. I can only do this, or need this, with the Defiant as the Encore is pushed into a fireplace and does not run as hot as the Defiant.

I would have though that by design when the flap closes it would cut off all air and the stove temp would come down -- that's how thermostats should work.

No. In modern stoves, the primary air is never 100% closed.

I'm concerned that even when that's happening I'm getting air in somewhere else that makes it hard to control. But where might that 'somewhere else' be??

Their are secondary air holes in all modern stoves. So, your theory is factual. If you minimize the primary air that should be plenty to control the stove during excess temps.

 

[defiant3]

2 things: Check to be sure the 2ndary air probe is intact. It should be like 3" long and not look all "used up". No on ever thinks of this, even exoerienced stove people.

Also, there are bleeder holes in the ash pan area which you can block off. It's cheating I know, but here we are mid season, and do what you gotta do at this point, figure it out in the spring. They are sort of hard to find. 2190 has them vertically to the left and right of the ash pan door just an inch or two back inside the ash pan area.

 

[defiant3]

My guess is the top needs resealing/replacing, and a really thorough going over by someone who knows their shyte.