Troubleshooting

[Heat Transfer Guy]

I had been running my Quadrafire insert with the air control fully closed entire time right after fires started. Now something is clogged with creosote. Where to look first?

After fire is going I used to get air rushing in when I crackd the door open. Now air and smoke blow out at top of door hard when cracked open. I see good flow out of top of chimney, which was cleaned and not too sooty last season. I have run the last few fires with air control fully open. That used to burn all creosote off the glass. Now center of glass got clear, but no hot airflow on left and right sides of glass, which have stayed black. Not able to get a huge yellow flame when air control fully open. It is partially blue flame. Seems like not getting enough fresh air.

 

[kennyp2339]

Look at the anatomy of how creosote forms, usually its a top down issue since once the water vapor condenses creosote deposits start forming. Check the chimney cap, send the brush down the pipe then empty the top of the inserts baffle where stuff can fall and collect reducing draft, draft is the engine that drives the stove, poor breathing is poor results.

 

[EatenByLimestone]

Yeah, chimney is the 1st place I'd be looking.

 

[stoveliker]

And then make sure your wood is dry. And burn hotter.

 

[Heat Transfer Guy]

Thank you for above replies.

The insert is working differently with the same dry wood.

I think I caused the problem by running all fires with air control closed instead of hot fires like @stoveliker just suggested. 3 full loads burned with air control fully open for hotter fire has not fixed the symptoms I described in first post.

I was thinking problem was in insert because insert has never been cleaned and chimney and cap have been cleaned. BUT, I understand the advice. I will check chimney, cap, and remove baffle in case debris has dropped onto it. Thanks for the direction guys.

 

[Heat Transfer Guy]

All fixed now. @kennyp2339 gave me solution and explanation 4 minutes after I posted. I found about a third of the diamond shaped openings in my small chimney cap were clogged with creosote.

I have heated with wood for 7 winters. After 5 winters' use I cleaned my chimney flue for the first time and got about a quart of creosote, which didn't seem that bad to me. And found no clogging of the chimney cap. So I got over-confident, lazy, and forgot about having regular hot fires with air control fully open to burn off creosote before it builds up too bad. All I was thinking about was keeping the heat in my house instead of losing it up the chimney. I got into the habit of filling insert, lighting it up, and then just a choked off burn. A rookie might try closing the air control to get less heat, but the correct way for less heat is filling with less wood, then adding a little wood to keep fire going. Lesson learned.

 

[stoveliker]

I would add to that that "burning fully open to burn off creosote" can be a dangerous proposition. It's better to 1. not produce creosote in the first place (i.e. have drier wood, so that one can turn down the stove more while keeping decent (secondary) combustion going), and 2. keep your chimney hot enough so that whatever you produce does not condense. Of course the cap will always condense some as you can't keep it hot enough. You can't "burn it off" of the cap (unless you have a full-blown chimney fire).

So, yes, I agree that some changes to burning habits are probably good. But I suggest that seriously looking into the fuel dryness would help a lot too.

 

[Heat Transfer Guy]

Ok, that makes sense, you can't burn off a creosote build up on the cap with 3 hot fires like I tried, before I knew where the problem was. I understand your point, and best I need to avoid cold burns with large smoldering unsplit logs with the air control closed. In my particular case wet wood is definitely not a factor because it was cut many years ago. The clean burn is the blue secondary burn that I have most of the time. Should be all of the time.

So the final question, under normal circumstances, is it recommended to have a fully open air control, with a huge fire for 10 minutes every few fires to maintain a clean flue? It sure helps cleaning the glass, lol.

 

[stoveliker]

I would still spend $30 on a moisture meter. (It depends a lot on how it was stored since those many years ago.)

In any case, I don't think a 10 minute high fire helps maintain the flue. The point is that what is deposited on the flue will not get off by the flow of a stove burning hard. If it is creosote (rather than fly ash or fluffy soot), it'll only come out with a brush or chimney fire. (Or, in very bad cases, special chemical cleanings costing a fortune.) At least this holds for anything 3 ft above your insert and up.

I don't know your (type of) stove well enough to give good burning procedure advice. However, the secondary air (that I believe the insert provides), is meant to burn half-burned stuff (smoke, gases). This is the stuff that creates creosote deposits in a (too cold) chimney.
Hence, if you dial down the air to smoldering AND secondaries disappear, you are smoking, dirtying your chimney (and the great outdoors). It's best done in steps (keeping flue temps below say 850-900 at the highest stage, and above 212 F minimum at all places, including the top of the chimney pipe).

There are others that are far, far better suited to suggesting how to burn with your insert.
It'd be good to know what firebox size it is (you were trying to get longer burns, and maybe a recalibration of what is possible is in order too?).

 

[Heat Transfer Guy]

My wood is stored under roof cover, lots of airflow, in dry Southern California. Although we see low 30's most mornings, we often see 80's that same afternoon. It's been sitting here 2 years and was cut and split a couple years before that. 7 years ago I got some experience trying to burn wood that was cut less than a year prior, so I know how to recognize wetter wood. It starts differently and puts a white haze on the glass. I have a moisture meter, just lazy to split a piece to use it.
Firebox is Grand Voyageur. By "longer burns" I meant having enough hot coals 10 hours later to restart without using kindling.
Thanks for your input, @stoveliker. Perhaps 8 years has confused what I remember reading on this forum about burning off creosote as it starts, before it gets bad enough to do what it did to me. I really don't know how hot my chimney cap gets. I do know previously I avoided this problem for 7 years.

 

[stoveliker]

Ok, your wood sounds good.