Understanding the Inner Working of PH

[Berner]

New to the burning world and trying to understand what exactly is going inside of my Progress Hybrid.

I'm getting ready for the overnight burn. I turn the bypass to open and the air all the way up. Let the draft establish itself for a few minutes. Stove top temp is around 350 with a large bed of coals. I load the stove up as much as I can and close the door. Leaving the bypass and air all the way open I sit and observe.

The flames start low and within minutes I have a firebox full of flame. There is a lot of cracking as the stove adjusts to the new temperature. Within another minute the fire is raging and sounds like a wind turbine starting to pick up steam. I cut the air down to half leaving the bypass open. Now the turbine sounds come and go in a rhythm, pulsing on and off every couple of seconds. This lasts for a half minute or so and then then the draft evens out. At this point the logs are starting to be fully charred and I feel comfortable closing the bypass. Here I leave the air at half for a few minutes but the flame dies out a little so I open it back up to full. Another few minutes pass and the flame looks like it is raging out of control again. Here I close the air down to half for a few mintues then down to a quarter and finally down to a pinch above closed where it seems to cruise nicely.

My questions are as follows:

1) Should I be closing the bypass before I make my initial air adjustment?

2) What is the jet engine sound and why is it pulsing when the bypass is open and the air is half open?

3) I seem to be doing a lot of tinkering during the first 30 mins of the fire. From the stuff I read on here everybody just loads it and brings the air down a couple of times until 20 mins later they are cruising for the night. When you guys stuff it and let it sit with everything open for 10 minutes doesn't the fire go crazy? It seems like this thing is going to explode after 2-3 minutes of running it wide open, I can't imagine doing it for 10. Is the stove built for doing this?

Thanks in advance for any help.

 

[fire_man]

I think I know the jet engine sound you are talking about. The flame is roaring and you hear a pulsing vibration noise coming from the air intake. That's about when my faithful Labrador Retriever makes a quick exit from the room. To answer your questions:

1. I close the bypass but leave the air adjustment open a tad(about 1" from closed) for 3-4 minutes before fully closing the air down. This gives more reliable Cat light-offs because it forces the cat to get hot sooner.

2. The jet engine sound is turbulence in the air intake. I don't know why it pulses, but I agree it does. I shut the air until the pulsing stops (but there is still a very good flame going). I find the turbulence so great that I get a smoke smell out of the air intake if the pulsing goes on too long.

3. I definitely warm the firebox for 10-15 minutes each time so that the wood is well charred. Yes the fire does go crazy but as soon as I hear the pulsing noise I dial it down until it just barely stops pulsing. I don't think you could hurt the stove in 10-15 minutes unless you were starting the stove from stone-cold. As long as the firebox is already hot, a roaring flame for 10-15 minutes is not going to hurt the stove.

 

[rideau]

Sent you a PM

 

[Slow1]

Wow you guys leave your air open far longer than I do on a hot (350*) reload. In that case I'd likely only open the air about 50% to start with, load the stove, close the door, then just wait until the flames are covering the wood (perhaps 5 minutes) then shut the cat (leave air at 50%) and then after a minute I close the air down until I see a nice steady secondary burn on top. Eventually I will go back and close the air down more perhaps, but generally not.

I've only had one loud vibration noise - it was with the air almost shut down and it appears to have been the air intake butterfly valve vibrating due to the air being pulled through it - at least that was the theory given from WS folks and it seems to match the situation very well.

 

[Berner]

Looks like there are a lot of different methods and maybe I need to find the one that works for my setup. What gets me is that every time I leave the bypass open on a reload it is only a matter of time before the jet engine sound starts and usually when I cut the air the jet engine starts to pulse. The air intake makes sense. My setup is in a tight spaced fireplace so its pretty tough to look back there during a fire.

 

[Berner]

I think I know the jet engine sound you are talking about. The flame is roaring and you hear a pulsing vibration noise coming from the air intake. That's about when my faithful Labrador Retriever makes a quick exit from the room. To answer your questions:

1. I close the bypass but leave the air adjustment open a tad(about 1" from closed) for 3-4 minutes before fully closing the air down. This gives more reliable Cat light-offs because it forces the cat to get hot sooner.

2. The jet engine sound is turbulence in the air intake. I don't know why it pulses, but I agree it does. I shut the air until the pulsing stops (but there is still a very good flame going). I find the turbulence so great that I get a smoke smell out of the air intake if the pulsing goes on too long.

3. I definitely warm the firebox for 10-15 minutes each time so that the wood is well charred. Yes the fire does go crazy but as soon as I hear the pulsing noise I dial it down until it just barely stops pulsing. I don't think you could hurt the stove in 10-15 minutes unless you were starting the stove from stone-cold. As long as the firebox is already hot, a roaring flame for 10-15 minutes is not going to hurt the stove.

Have you got the pulsating turbulence noise with the cat closed? The cat closed is usually where I hit my sweet spot and everything runs smooth. I think a call to woodstock is in my near future.

 

[pen]

Have you tried what Slow1 does?

 

[rideau]

As I sent in the PM, you are losing the pulsating when you close the bypass because you are making the air path slower, more circuitous, effectively reducing your draft. Just keep your air intake lower, as detailed. Your stove will be happy, and so will you.

 

[fire_man]

I never get the turbulence noise when the cat is engaged. I also have a tight spaced fireplace which may have something to do with encouraging the pulsing resonance.

Slow1 has an interesting dial down procedure when loading a hot stove. He uses less time and less air (50%) with the bypass open, but leaves the air for a short time at 50% with the bypass closed. In any case, it seems best to engage the cat but don't dial the air down too quickly.

 

[Berner]

Thanks for all the help guys. I did try what Slow1 suggested last night and it worked. I think I'm still trying to get it out of my head that I need active flame in the firebox. Must be a newb thing that I need to break. Looks like the jet engine noise is too much draft mostly caused by a hot reload with lots of coals.

The funny thing is during the whole stove installation I was paranoid that I wasn't going to have enough draft. With lots of tall trees and barely meeting the 10/2 rule. I'm thankful to have the opposite problem.

 

[Backwoods Savage]

Wow you guys leave your air open far longer than I do on a hot (350*) reload. In that case I'd likely only open the air about 50% to start with, load the stove, close the door, then just wait until the flames are covering the wood (perhaps 5 minutes) then shut the cat (leave air at 50%) and then after a minute I close the air down until I see a nice steady secondary burn on top. Eventually I will go back and close the air down more perhaps, but generally not.

I've only had one loud vibration noise - it was with the air almost shut down and it appears to have been the air intake butterfly valve vibrating due to the air being pulled through it - at least that was the theory given from WS folks and it seems to match the situation very well.

Did you mean you close the bypass here Slow?

 

[Slow1]

Did you mean you close the bypass here Slow?

Indeed. "Shut the cat bypass" would have been more precise I suppose. Perhaps I should just say "engage the cat"... all the same thing