Google shows a green mountain 60. That’s a hybrid stove with a cat. He needs to brush up on the manual on how to operate a cat stove and what to expect of it.
Probably a combination of moisture content in the wood and not enough oxygen. When wood starts to burn it takes more air to break into combustion (visible orange flames) than at its burning stage. Once wood starts burning good and it’s humming along you can start to cut down on its oxygen need—Kind of like the “cruise control” phase. Fires need lots of oxygen to get going and less to maintain once they get momentum. The blackening of his wood without flames makes me think not enough air. Does he just throw in a piece of oak and then immediately shut the door all the way with the air controls choked down? I would bet if he just opened the door when the wood is blackening like that it would quickly burst into flame from the oxygen rush. When I start a fire I leave the door cracked open about an inch for the first maybe ten minutes or so then close it all the way in two or three more steps over the next ten minutes. My stove model (quadrafire explorer 2) has a spring loaded air control valve that slowly goes from all the way open and chokes down over the next 15-20 minutes. It is designed for this very process of a fire and it is at this point I engage that. Burning in a wood stove is not like burning an outdoor campfire or open fireplace where you can just light a match and sit back or walk away. Since he is new he has yet to discover this. It takes several burning seasons to learn how to burn correctly and “dial in” with the particular appliance one has.
I've had both oak and cherry burn like that, usually with a good coal bed and the air dialed back quite a bit. Sometimes I've sat and watched the whole surface of just loaded splits burn like grass in a field , turn black and then thought the fire went out but it's OK. The weathered surface just burns off first for whatever reason.
One thing to keep in mind is that a stove with a cat will usually have less active flame than a non cat epa, especially in the long burn cruise mode. There are times when you look in on a catalytic stove that it looks like its not burning well but that's how they operate. It's still doing its thing through the catalytic reburn. Sent from my SM-S536DL using Tapatalk
That pic almost looks like if you just chucked a single piece in on the hot coals and shut the door, leaving the air on minimum the whole time...which can work if the wood is dry, but its going to often times turn into charcoal like that too...I've seen elm do that too...not much flames, long lasting coals.
Thanks for all of the replies. I stopped over his place yesterday. I have never held a moisture meter let alone used one until I was there. His only has a setting for firewood and a setting for lumber. The moisture content on a fresh split was under 15% so his wood is definitely dry. I also gave it my knock test and got that high pitch sound so I knew it was dry. There is an air vent piped right into the stove which he has checked to make sure it is clear. He runs the stove in the optimal (catalytic) range as indicated by thermometer on the unit. I shared what I had read on here up until yesterday morning. I also brought him 3-4 pieces each of some dry cherry, oak, red maple, and ash for him to burn to see if he gets the same results. I'm curious what he will have to report back.
jrider my stove, a Woodstock cat likes to be filled at least 2/3 full; 3.2 cub ft fire box. Then Gotten up to temp and set in cruise mode.. Can keep Stove top temps around 300 for 8+ hours.. you add 2 pieces pieces at a time it doesn’t work as well. It doesn’t get hot enough to engage cat and before firebox temps drop. Stove has inside and out lined in soapstones
