For those using key dampers......

[laynes69]

Do you close it to a certain point and leave it? Some of you know I use a wood furnace with a barometric damper. I checked our flue and chimney after more than a month of burning and a couple dozen plus cold start fires due to the shoulder season. Of course there was some glaze after the barometric damper because of 60 degree air entering the flue. Where the snout enters the chimney there was a fine layer of soot so nothing to worry there, but some glazing towards the top of the chimney at 30 some feet. Just a paint thin layer, but its there.

Where I am having thoughts is the normal flue temps for our furnace with it closed down and burning cleanly we are seeing around 175-200 on the surface of the flue, which is fine. The problem is the baro allows for that 60 degree air to enter and after that I am seeing temps in the low 100's. With our chimney being 32' tall even though its insulated the gasses cool too much at the top.

I have more draft than I know what to do with and the company that makes the furnace tells me key dampers are for old wood burners and not for epa stoves or furnaces. They want a baro used, but I need as much heat in that flue as possible. What I have thought is if I set the damper during a hot fire with a manometer, then the draft speeds shouldn't go over that once the fire dies down some. I have been experimenting with a key damper and closed the baro, but I want some feedback on those who use a key damper. My wife doesn't want to do more than needed with the furnace. So if I can set the key and leave it I would be happy. Can it be done that way?

 

[HotCoals]

First season on the furnace?

 

[BrotherBart]

All I can tell ya is after the stove in the basement with the thirty plus foot liner is up to temp and the flue is drafting I close the key damper almost all the way and leave it until reload time. Of course I have no experience whatsoever with a wood furnace.

 

[laynes69]

No, second season but first with the liner. It has changed things 100%. Manufacturer has specified flue speeds, so I am trying to figure out my options on how to go about it. Anyway I do it, I need to slow down the draft.

 

[oldspark]

Not sure if this is any help but here goes, I used a damper for 30 years on my old stove and what I read way back then was to close the damper until a little smoke comes out the door and then open it a hair and that was the best place to set it, this is what I did on my old stove.

 

[HotCoals]

I watched your video..pretty cool!
How about a rain cap..would that slow your draft down some or make it stronger or do nothing?

 

[laynes69]

I've adjusted the rain cap lower, and nothing helped. I don't have a problem with the baro with buildup. Its the fact its robbing temps in the chimney. I assume it operates the exact same as a EPA non cat stove. Open the primary let the firebox get hot and then shut down the primarys so the secondaries burn. Do I keep it open until I close the damper on the firebox, or load then close it and do the normal thing?

 

[HotCoals]

I guess you lost me.
So you're saying you are not worried about creosote build up in the chimney?

 

[HotCoals]

Ok ..I re read your first post.
Every stove I have had I just opened the damper for a min or so..loaded the wood in then closed her up again..as long as there was a good bed of coals anyways.
You don't have to warm a cat up so i would think you would be ok doing it that way also.
Sooner or later those secondary's will kick in..right?
Just curious..does your wood furnace have a primary air activated by a bi-metal thermostat?

 

[laynes69]

Primary air is activated with a digital thermostat in the living room beside the gas thermostat. When its cold out its very accurate. I always open the damper and load the furnace. When the fire gets hot enough, then the damper can close and we get good burns. With it being setup with a secondary heat exchanger and a large blower, the flue temps are probably lower than most EPA stoves. So I thought I could eliminate the cooling of the top of the chimney, by eliminating the baro and switching to a key damper. The one thing that made me leary of doing it was the company saying its dangerous. I knew they were used on pot belly stoves and older stoves with higher temps. I want a good draft for the furnace to operate properly, but low enough so I can keep my burns and put more heat in the home.

 

[HotCoals]

I see.
Maybe you need to invent a damper control motor that works off of flue temp..lol.
Good luck.
All I know is my old Bk non cat the damper was just about always turned sideways..but it has a fairly good size hole in it.
Just opened it to fill and would leave it open for 10 mins or so after filling ..then I would shut her down.
Cleaned the pipes once a year with no probs.