Page 1 of 1

Brunco Wood-coal Stove bi-metal draft control

Posted: Sun. Jan. 14, 2018 2:17 pm
by nightowl66
I have a Brunco Hearthglow that I burn mostly wood in, some coal. I had the bi-metal coil spring lever come loose and readjusted to where the draft flap is closed when the stove is cold and the lever is up as the instructions state.
I am having a problem when the stove is burning to temp and I raise the lever to close the draft control, it closes, then opens when I raise it all the way up. It seems like no matter how I adjust, it isn't right. Almost like the chain is too short that goes down to the flap. Could the coil spring be going bad and moving too far?
Thanks for any help.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Sun. Jan. 14, 2018 3:01 pm
by freetown fred
They do go bad. Rarely but not out of the question.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Sun. Jan. 14, 2018 3:45 pm
by rberq
The manual for your stove says, “The bi-metal draft control should be adjusted so that the damper is just touching closed when the stove is burning at the desired temperature” – NOT "when the stove is cold." If it was working OK before the lever came loose, then I doubt that the coil spring suddenly went bad at the same time. More likely you reattached the lever a little bit wrong relative to the spring position. Tinker with it – hopefully you can do so without getting burned. :?

http://fireplaces-rochester-ny.com/manuals/BRUNCO ... 0Stove.pdf

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Sun. Jan. 14, 2018 3:59 pm
by freetown fred
About a 1/8" while hot & keep an eye on it.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Mon. Jan. 15, 2018 1:48 pm
by nightowl66
rberq wrote:
Sun. Jan. 14, 2018 3:45 pm
The manual for your stove says, “The bi-metal draft control should be adjusted so that the damper is just touching closed when the stove is burning at the desired temperature” – NOT "when the stove is cold." If it was working OK before the lever came loose, then I doubt that the coil spring suddenly went bad at the same time. More likely you reattached the lever a little bit wrong relative to the spring position. Tinker with it – hopefully you can do so without getting burned. :?

http://fireplaces-rochester-ny.com/manuals/BRUNCO ... 0Stove.pdf
I have installation instructions for the stove that states, "Flap should be closed when control handle is parallel with the top of the stove. Adjustment of the chain may be necessary after the stove is in use."

I did this when the stove was cold, with the lever in the up position, which closes the flap, I left just a little slack in the chain. Now when the stove is hot I can adjust the damper how I like it. The problem is if I would raise the lever all the way up when the stove is hot, , It takes the end of the spring where the chain is attached and rotates it past its lowest point and raises it again.
If you were looking at like a clock, the end of the spring where the chain is attached, as it heats up, the end of the spring moves from the 3 0'clock position to the 5 o'clock position. If I raise the lever, it rotates past the 6 o'clock position which tightens the chain up and opens the flap. If the stove were to get hotter for some reason after I set it where i want, it could actually open the damper instead of closing it.
So I readjusted it when It was hot, but now the damper wont close all the way when it cools down. It is like the chain is too short, but it is the same as it has always been.
I have had a couple stoves with this type of damper control and have never had this problem before.
What does the spring do when it goes bad?
Sorry for the long post, I tried to explain it as best I can.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Mon. Jan. 15, 2018 2:06 pm
by franco b
With the stove at a heat you want, and the lever at a mid position, adjust the chain so the flap is closed or nearly so. This assumes you can do it without getting burned.

Vermont Castings Vigilant also has a way out movement when cold.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Mon. Jan. 15, 2018 3:29 pm
by rberq
nightowl66 wrote:
Mon. Jan. 15, 2018 1:48 pm
So I readjusted it when It was hot, but now the damper wont close all the way when it cools down. It is like the chain is too short, but it is the same as it has always been.
When you say "cools down", do you mean the fire is out and the stove is room temperature? There's no reason the damper should close all the way on a cold stove -- it is "trying" to let in more air to make the stove hotter, so it opens. And with the fire burning, also, at a given lever position the damper should open more as the stove cools, and close as the stove gets hotter.

If you have resolved the problem of the spring end going past the 6 o'clock position, then it sounds like you're good to go.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Mon. Jan. 15, 2018 4:11 pm
by nightowl66
rberq wrote:
Mon. Jan. 15, 2018 3:29 pm
When you say "cools down", do you mean the fire is out and the stove is room temperature? There's no reason the damper should close all the way on a cold stove -- it is "trying" to let in more air to make the stove hotter, so it opens. And with the fire burning, also, at a given lever position the damper should open more as the stove cools, and close as the stove gets hotter.

If you have resolved the problem of the spring end going past the 6 o'clock position, then it sounds like you're good to go.
Yes, room temp. I set it like the instructions that I have, "Flap should be closed when control handle is parallel with the top of the stove. Adjustment of the chain may be necessary after the stove is in use." This was for initial installation instructions. Maybe when the stove was new the coil spring wasn't attached. Stove was in my house when I bought it.
I had a Lilly stove in my old house with a similar setup and you could close the damper by raising the lever when the stove was cold.
I have another Brunco in the shop, but the spring is completely covered unlike the one in the house, a slightly different model, the flap closes all the way when cold and the lever is raised all the way.
I'll keep playing with it. I thought I was able to close it all the way before, I haven't used it much. I have a Buck stove downstairs that is used most of the time.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Wed. Jan. 31, 2018 2:08 am
by nightowl66
20180124_010542.jpg
.JPG | 799.6KB | 20180124_010542.jpg
Turns out it was the spring.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Wed. Jan. 31, 2018 8:42 am
by rberq
nightowl66 wrote:
Wed. Jan. 31, 2018 2:08 am
Turns out it was the spring.
Wowser! Looks like somebody tried to "adjust" it in the past. :o Or it just got tired.

Re: Brunco Wood-coal Stove bi-metal draft control

Posted: Wed. Jan. 31, 2018 9:20 am
by coalfan
ouch !!!!!!!!!!!!!!!!!!!! get that mess changed asap wow !!!!!!!!!!!!!