Sounds like thunder!

[bosshog919]

Ok guys I have a new Harman P35i, lately I've been getting wht sounds like thunder in the chimney. Not all the time but off and on. It's 17 feet to the top of the chimney with the cap and 4 inch stainless pipe. Maybe this is normal, any help appreciated.

Burn Baby Burn

 

[stoveguy2esw]

sounds like its "wuffin" does your fire change when the noise is occurring? usually it will "quiver" then go smooth as the noise subsides. doesn't hurt anything but can be annoying too much air usually is the culprit

 

[bosshog919]

Fire changes jus a lil bit..too much air like coming down the chimney or too much air like in the insert space??? Thanks for the quick reply!!

Burn Baby Burn

 

[Bioburner]

Never heard of "wuffin" before. Seems every couple weeks someone has the V1 buzz issue.

 

[stoveguy2esw]

Never heard of "wuffin" before. Seems every couple weeks someone has the V1 buzz issue.

that's what we've always called it (dates back to the "redneck stoveworks" days) we figured we build em we get to make up the terms for what they do

the sound is similar to the "earthquake" noise in low budget movies, fades in and out usually as a load of fuel gets going and fades out as the fuel is consumed.

one of the things we used to do to calm it was to restrict the intake just a bit. this creates kind of a "speed bump" for the intake air and that usually makes it go away

 

[Bioburner]

I am very familiar with the syndrome. When folks went from fuel oil fired boiler to propain, we would get it and would run and turn the stat down and refire the heater. Had an engineer uncle that would borrow our shop for various projects and played with various liquid fired rockets and jets would do this to scare my Grandma.

 

[stoveguy2esw]

its actually a "stall" happening repeatedly at high speed, similar to a compressor stall in a turbine engine, the air gets into a shudder instead of a smooth flow

 

[Bioburner]

Lennox pulse furnace, based on the V1 German rocket

 

[stoveguy2esw]

ohhhh, ok, a "pulse jet" furnace, interesting concept

 

[Bioburner]

Worked well, was one of the first over 90 percent efficiency furnaces. Had some issues with exchangers rusting out and of course noisy.

 

[stoveguy2esw]

yeah i expect so, the "buzz bomb" was a pulse jet design with what was essentially a superfast series of explosions driving it, the intake shut it went off and the intake opened again in rapid fire succession to create thrust (as i remember anyway, been a while)

 

[Bioburner]

And could be run without the shutters if the exhaust pipe was tuned properly. History Channel on the history of journey to space I think.

 

[fmsm]

it's a known issue with Harman's. My P35i only does it with Green Team Pellets. Any other pellet, no noise. Pretty weird!

 

[Bioburner]

I can force ours to do it by pushing the feed rate.

 

[bosshog919]

Thanks for all the knowledge bout rocket fuels and what not! Been burning green supremes lately as shoulders, probably my harman telling I should not have been feeding him tht chit! LolWill see wht happens with the Barefoots!

Burn Baby Burn

 

[tjnamtiw]

perfectly normal, especially on start up when the fire may be a little too big. No big deal.

 

[lbcynya]

If you want to be more "city" you can call it woofing... Happens on the XXV primarily in stove temp. You can also search for "woof" to read about it more. Aside from altering stove settings, not much you can do.

 

[Tdamico]

My accentra woofs. Annoying, but I'm getting used to it. Thanks for starting this thread!