Quadrafire Millenium 2100 ACC Dirty Window Problem?

[danking49]

This stove leaves a black soot spot on the same location of the glass every time I've fired it up since I started using it this Fall. When I asked Quadra-Fire for an opinion, they referred me to the local dealer who insists it's a glass gasket problem. He's "tightened" the glass clamps once and actually replaced the glass and gasket today; but no change. I have to assume that the dealer would have noted any door defects when he changed the glass today, so I'm left believing that either: a. There is a problem with the stove or b. this is a charactoristic of this stove model that I'll just have to live with.

Does anyone else out there have this problem with their Millenium or Step-Top from Quadrafire?

 

[BrotherBart]

Put a straight edge flat against the top of the inside of the door and see if it is straight. Then do the same to the front of the stove where the gasket makes contact.

 

[precaud]

The primary airwash system in the Quads is a weak spot in their design, IMO. They don't leave the cleanest glass, but that's pretty gross.

When the stove is cooled down, get a lamp and a mirror and examine the airwash gap above the glass. It looks like something may be lodged up there above that dark spot.

 

[danking49]

Nothing appears to be warped and the door passes the "dollar bill test" just fine. Airwash channel above the door appears clear alone the intire length; although one of the mounting screws is located exactly in the middle of the area where this dark spot occurrs every time.

 

[bokehman]

one of the mounting screws is located exactly in the middle of the area where this dark spot occurrs

Is that screw a bit proud?

 

[danking49]

Both airwash channel mounting screws are equal.

 

[bokehman]

Are you burning hot enough? Is the wood seasoned properly?

 

[danking49]

Flue temp almost always between 500 and 700. Dealer has already suggested getting a stove-top thermometer up to 900 as a solution. While having me burn my house to the ground might solve HIS problem fixing this, that's not an idea I'm real comfortable with as that equates to a continuous flue temp around 1100!

The photo shown is a best case scenereo giving Quadra the benefit of the doubt re: how "seasoned" the wood is by who's definition. Generally speaking, at the end of one, maybe two, days the entire glass always needs cleaning. That appears to be just how it is with Quadra's current air wash system; weak and ineffective at best. The black area shown in the photo occurs about one hour into the burn while the remainder of the glass is essentially clean.

 

[precaud]

That isn't a mounting screw, it's the airwash channel gap adjustment screw. You'll see one on the right side too. Use a 5/32" hex head to adjust them.

What you're bumping into is the main weakness of the Quad airwash design, which I've wrestled with ever since I got mine. Do a search for posts on this stove and you'll see my process documented, except the final episode which hasn't been written yet.

The fact is, on the 2100 (and maybe other Quad models) the left side airwash is lower velocity than the right. As a result, the glass burns dirtier on the left than the right, and the stove burns hotter on the right side, with a burn pattern that typically pushing most of the flames to the left side as they exit the firebox. Initially I found many little things that I thought were causing this, but correcting them made little difference. The only things I have found that could cause this is the door latch design and the symmetry of the air gap. I'll explain.

The primary air enters at the bottom front center of the stove, gets preheated while it passes through channels along the front corners, and gets blown/pulled into the airwash channel above the glass. Your chimney is putting equal pressure on both sides of the airwash channel. The left channel has no obstructions, but 50% of the right channel is blocked by the cutout for the doorlatch mechanism. So the air on that side enters at higher velocity than the left, accentuated by it expanding as it is heated. Why Quad would design it this way is beyond me.

So, that's the basic mechanical reality. First thing to do is measure the width of the air gap on both sides at the screws. I recommend using feeler gauges for accuracy, as the small blades on most calipers aren't long enough to reach up into the gap. Quad says the gap should be 3/16" at the screws. My experience is that the actual number isn't as important as the gap being the same on both sides. Without going into all the details as to why, I'd recommend adjust the bigger one down to match the smaller.

Let us know what you find and we'll go from there.

 

[danking49]

Precaud,
What you described might the ACT design, but my ACC is very different. The air for the wash "system" appears to me to enter via the primary air control on the top right side of the stove, directly to the airwash and primary air feed holes along the top front. There are no allen screw adjustments for the airwash channel of this ACC model; only a slotless flathead screw on the front, through the channel, then secured on the inside by a regular hex nut in two places on either side with some sort of a spacer in the middle. The air wash gap appears to be consistant across the stove; both cold and hot (looking for heat warping).

I did read your posts about the ACT stove (great read by the way), and it looks to me like Quadra read it incoporated at least some of the ideas into the ACC; although as you describe, the stove still burns decidedly from right to left.

There is, however, a small gap between the air wash channel and the left sidewall of the stove (right side is sealed). I am going to try closing that up with a little stove cement and see if that changes anything. With the temps headed for the lower 60's tomorrow (beach weather!), it might be a few days before I light it off again; stay tuned!

Thanks
Dan

 

[precaud]

RI,
I didn't know they had changed the routing of the primary air on the ACC models. However, if, as you describe, the air is being fed into the airwash chamber from the right side, then the problem is still the same; the left side is getting less air than the right. I'm stunned that they continue to incorporate asymmetrical airwash systems. It's a dark spot (literally!) on an otherwise well-designed stove.

PS - I'd be VERY uncomfortable with 700F temps at your stovepipe. Quads do tend to run hot, but that's excessive. Measuring 10" above the stove, pipe temps on mine typically run 400F lower than the stove top temps; I rarely see higher than 500F on the pipe and 900F on the top. If you're seeing 700F on the pipe, then your stove top must be glowing!

 

[danking49]

Nope, not glowing at all. With stack measuring 700 at 18", the top was measuring between 400 and 500 depending on if the fire was building or declining. I don't even use the stove top thermometer anymore; I'm only concerned with keeping the stack hot enough to avoid creosote building up and low enough to avoid a chimney fire. The stovetop temp seems irrelevant to me as long as nothing is glowing and the whisling teapot on a trivet is quiet.

 

[precaud]

Hmmm... it seems odd that your pipe temp is higher than that of the stove top. On a stove with a big, unbaffled top plate like the 2100, that shouldn't be the case.

Besides the dark spot, how are you liking the ACC version?

I continue to be very impressed with my 2100 ACT. Last night, put I two 6" pinon rounds in at 7:30pm, the flames died at 10:15, a good, solid burn (top at around 800F) the whole time. Shut it down, went to bed, woke up at 6am with plenty of coals to start up again. With efficiency this good and operation so simple, I'm willing to overlook the few niggling details it has... life is good.

 

[danking49]

Generally speaking I am impressed with the stove. It easily keeps the entire 1,100 sf house warm (80f in living area, 70f in bedrooms at other end) at 15f-20f outside with howling winds. Once a good bed of coals are established I can throw in two or three good size oak rounds and not have to feed it again for 3 or 4 hours.

The "automatic" ACC feature is a waste of time and money in my opinion. Sometimes is works okey, other times it's just not appropriate for the actual burn cycle; it chokes down too fast for an early oak fire and too slowly for maple over a good established coal bed. Connect that automatic air damper to a flue stack thermometer instead of that stupid timer and you'd have something useful!

 

[precaud]

Sounds great. I agree on the automatic ACC. And I like your idea about the stack temp monitor to control it instead of a cheesy timer. Can it be defeated so you can work the startup air manually?

 

[TMonter]

How seasoned is the wood you are burning? Have you tried other wood types?

I get the same spots on my 3100i when I'm burning less than seasoned wood or certain types of hardwood like Birch which burn slower and longer.

 

[danking49]

Tmonter,
Stove burns between 500 and 700 (550 more often than not) with little to no smoke; primarily with white oak. Wood is two years old and dry. Same spot occured when I tried Ecoflamme bricks last week, and some lumberyard kd spruce scrapes a month ago. When I do hit the occasional wet log from the end of the pile or something, the entire window gets dirty as would be expected and is normal operator error stuff. I'm just trying to figure out what's causing that darned one dense black area that happens no matter what I burn.

Thanks

 

[mike bove]

I also have a quad 3100i ,definately a big difference with seasoned wood and not so seasoned, Big diff. One thing u might want to try is vacumming around the inside air channelsand gasket, when i I do this my airwash seems to work better. And i sorta remember somebody saying metal filings getting stuck in there from production.

 

[TMonter]

It almost sounds like something is plugging those holes in the airwash system somehow or maybe some of the flow is getting diverted away from them. Can you snap a couple pictures of the airwash area on the stove? I'm not super familiar with the new Quad ACC design.

 

[danking49]

I see if I can get a few pics tomorrow night and post them up, but I did check the airwash channel very closely with a mirror and there are no obstrucitons anywhere along the channel except for the two mounting bolts and middle support tab that obviously belong there. I did, however, notice that while the right end of the channel is welded to the side of the stove along the entire end of the channel, the left side is only spot welded at the top with a small (1/16" or so) gap between it and the side for most of that end. That could be enought to cause an altered air flow on the left side to create this problem. That gap could also serve some purpose like expansion or something; so who knows. Wish there was some way to get beyond my boneheaded dealer and discuss with someone at Quadrafire who knows what they are talking about about. Either way, I closed the gap with a little stove cement last night. I'll let you know what happens after I fire it up tomorrow.

 

[TMonter]

You could try to cool the stove down and put some stove cement in that gap and see if that helps. Stove cement isn't permanent so it can always be scraped out later if need be. Also how long is the screw holding the airwash plate in place? If it's real long it could be disrupting flow in the airwash manifold, that seems unlikely but low pressure flow can be pretty cranky.

 

[danking49]

The two air wash plate screws go through a spacer in the air wash channel; so they really can't be "too" long. That spacer looks like it would create a lot of turbulence, but it's clearly there by design. If it is the cause, then it's a design flaw I'll have to live with. While it wouldn't be difficult to remove, I don't want to give Quadra any excuse for denying a warrantly claim; which as you pointed out, is why I've used stove cement to see if closing off the end of the channel works on a temporary basis. If so, I'll ask Quadra to have it welded or replace the box.

 

[precaud]

I had the same gap on mine up there, and sealing it made no difference.

 

[danking49]

Precaud,
Ditto on this end; sealing that opening on the left side of the air wash channel made no difference.
I also burned Evi-8 bricks for a day just to dismiss the un-seasoned fire wood theories; no change same problem.
So it's not the glass, not the wood, leaving me with what appears to be an inherent design flaw in this stove. NOW I understand why you invested the time attempting to fix the problem; apparently Quadra can't get a handle on it either.

 

[precaud]

Sorry to hear it, RI. I'm pretty confident that it's the asymmetry in the primary air feed that's the cause. This certainly isn't the only stove with that issue; my X33 feeds air into one end of it's secondary manifold and it does the same sort of thing.

Best I can tell from looking at the drawings in the manuals, comparing the ACC and ACT, they both use the same airwash chamber and U-shaped primary air channel tucked into the front corners with doghouse in the center, both feed the airwash chamber from each upper corner, and both have the same blockage in the right side vertical for the door latch. The difference is where the air is fed into said channel. The ACC looks like it feeds into the upper right corner, not far from the airwash chamber. Can you confirm this?

If this is so, then I don't see an easy way of dealing with this. The right side air path is short and direct and gets little preheating benefit. The left side path passes the latch blockage, wraps all the way around the front of the stove, and is tapped off by the doghouse air feed before hitting the left side airwash chamber.

This is an incredibly unbalanced air system. And a stupid design. Why do designers do this, just for the convenience of a marginally useful automated startup air control system? They have the entire back and bottom to use for such things, which would then allow a symmetrical air feed.

Enuf ranting for now...