This is my third season with my BK, since I've owned it this has this happen to me once each season now. When it's cold the draft is really strong, when I load the stove if I leave an opening or gap in the splits below the bypass the flames get sucked up the pipe and create what I can best describe as a blow torch type affect. This puts a crazy amount of heat into the pipe in a short period of time. I usually place a big split or a couple tightly placed split below the bypass opening to avoid this from happening. Last night I was letting my 4 yo son help me push splits into the stove after I placed them in. He can't really wiggle/push the bigger ones easily so I placed some smaller splits loosely placed in the center so he didn't have to get near the edges. When I did it I thought to myself hmmm those could cause some issues but I'll watch it. We were playing in front of the stove and I noticed the flames were concentrated in the middle of the wood and getting sucked right up the bypass opening. I turned the air down and it helped calm the flames down or so it appeared. What I didn't see was the gap in the back of the stove where the flame was still getting sucked up. A minute or two later I seen smoke coming off the pipe and knew exactly what happened. I closed the air completely and closed the bypass. I grabbed my IR gun and the double wall was 450+ at the first 45. Of course my first concern was a chimney fire but thankfully there wasn't enough stuff in the chimney to light off. I didn't hear any roaring from the pipe or train type sounds people describe. For good measure I went out and looked at the chimney, no flames, sparks or black smoke coming out and I also checked the chimney in the attic with my IR gun the temp was only 10* above the ambient temp in the attic. The pipe cooled down within minutes after turning the air down and closing the bypass. Last year when it happened to me it was only a day or two after cleaning the chimney. Just goes to show even though we do something one or two times a day for 6-7 months a year we can still have the opps moment. Maybe I'll make it through next season without this opps moment! If it happens at the wrong time with build up in the pipe/chimney I could have some real problems. It's one of the reasons I like to clean the chimney multiple times a season just in case. From now on if I think I might have one of those types of loads I'm just going to close the bypass right off the bat and let the cat get abused a little, I rather replace a 200 dollar cat rather than risking a bigger issue.
I've had the old single wall pipe glowing , not bright but a dull orange. I try to never walk away with the door cracked or the stat on full open. Stove pipe will handle some pretty hot temps, you are probably OK 1000° f continuous , 1700° for several minutes http://firewoodhoardersclub.com/forums/index.php?threads/max-stove-pipe-temps.1613/
I'm not really worried about the pipe, the paint didn't even change color or fade. The first time it happened I still had the 90* in the pipe the black paint was a dull black almost whitish after that event and the pipe was just fine. I've been avoiding it but I may break down and buy a flue probe due to the three-peat.
Glad all is fine Rdust. Sort of along the same lines. I was talking with Woody Stover awhile back about engaging the cat in the Buck as he has on at MIL's. My Buck stove manual says to close the bypass right away on a reload and leave the air open until the wood charges. I have been doing that and it seems to work fine but I was looking at the manual online the other day for something else rather than getting the hard copy out. The section committed to just the cat says to leave the bypass open until temp comes up so it sort of contradicts the reloading section. So I am sort of pondering this. When I let the fire catch and then engage it seems like it is hitting the cat hard with heavy flame and the other way you are putting some flame at it slowly until it gets going. Not sure which is better.
Good luck with that. Every year I know I will; burn some part of my arm, grab at least one flaming log, open a stove door too fast and suck smoke into the room, and forget that I haven't closed a damper or turned down the air resulting in a funny smell from the pipe and me sprinting down the gallery to tend to the 30 or the Defiant. You'd think I'd get better at the Wood Burning Stove Olympics...
The original Encore manual says that for a reload on a hot coal bed, to close the damper right after reload. Normal procedure is to leave the damper open until the stove comes up to 500+ then close the damper. Both work, but a cross between those works best for the Encore: reload on hot coals, leave damper and air open 5 minutes (only long enough to start the load not engulf it) then close the damper. Air still open until the flue temp rises over 350 (no cat probe) then slowly taper down the intake to cruising position. This ain't exactly a user friendly process but won't shock the cat and gets the load on its way.
Pulled the pipe over the weekend since it warmed up. Everything looked fine, no ulgies/crusties in the pipe or burned up pop corn looking stuff.
I've done the same many times. Those bypass temps can get away from you pretty quick. Your probably fine engaging sooner, those cat temps don't take long to reach 500+ and I know you have good dry wood.
I've had this happen a few times on my stove. Without the CAT going it's a fairly direct path from top of stove to pipe. Usually I can leave the air wide open when the first is first going and it's ok. Stove warms up, I can engage CAT and turn air down. Once in a while though the fire wants to get pulled hard into the pipe. I thought it might be from a stronger draft when it's cold, but I had it happen to me 2 days ago when it was 35* and humid out (normally a weak draft). Smelled the stove getting hot maybe 5 mins after I lit it. Well stove was barely even warm, but the pipe was at 450*+... outside of the double wall!
