Progress behaving differently this morning

[davidhite]

I've been enjoying my new progress for about 3 weeks now and haven't had it much above 550 stove top. This morning about 7:30 I went through my normal routine - filled it half way on the morning coals with several four to six inch splits of doug fir (15-17% mc) and a bear brick, let the fire get going and engaged the cat at about 275, then shut the air down completely.

Stove was unusually dark at first (no flames). After a couple of hours the stove top temp was up to 575 (which is a bit unusual as it typically levels off and cruises around 450-475). I then hear a slight "whoof" in the fire box, stove top is approaching 600 and appears to be rising quickly. I fiddled with the air lever to make sure it was all the way down, heard a tiny click as I put downward pressure on the lever and then heard another larger "whoof". Secondaries fired off pretty heavily for about 20 minutes then died down. Was getting a bit nervous as the temp kept rising and finally peaked at just over 625. Temp is now down to about 500 and the stove is cruising normally.

I don't know what was different about this morning. Same wood, same weather, same routine. Perhaps a rogue split or two got in the mix? Maybe more air was getting into the box because something was hung up with the air control?

 

[Todd]

Welcome to the forums. Have you checked your cat and screen for possible plugging lately? Woofing can be caused by gases building up and lack of draft.

 

[Waulie]

Welcome!

I've had that happen a couple times with the Progress. When it does happen, open the air a bit. You didn't have too much air, you had too little. Try closing the draft down in stages, if you're not already. If you turn it down too quick, you can get more gas than the cat can handle and get backpuffing.

The other thing to check is that the small air supply under the window is not blocked. This is designed to prevent backpuffing when switching from cat to secondary burn. I will frequently notice a bit of a "whoosh" when the secondaries ignite suddenly, but I don't think this is a problem.

Your temps were probably climbing so fast because you had more smoke than usually and the cat was going to town on it. Maybe you had a couple wetter splits in that load and/or you turned it down a bit too fast.

 

[davidhite]

Thanks Todd,

Your probably right about the whoof. I don't have the greatest draft, 22' of 6" pipe with a forty-five, outside temps in the low 30s. Perhaps conditions were just right this morning for the gas to build up.

I cleaned my screen and cat earlier this week. The screen was fairly plugged with ash before I cleaned it. It looks clean now.

I doubt it is related to the whoof, but I am noticing a strange metallic sound when I put upward pressure on the air control lever from the full down (closed) position. It's like a loud ping or click. It is not the shaft rubbing on the rear heat shield, but something inside the air control mechanism getting hung up and then releasing when upward pressure is applied to the air control lever. I don't recall hearing the sound prior to this morning, but I just may not have noticed it.

 

[davidhite]

Thanks Waulie,

I think you're right on. I may have had a wetter split in the mix and may have shut down too soon. I was't aware of the air supply under the window. I'll give it a look.