Greenwood/Seton Air Intake Damper Cycle Times

[DKerley]

Hello All,

It's burning time here again in the Yukon. Had the plumber install a 3 way mixing/diverting valve to keep the return water temp above 140 deg. hoping to prevent creosote build up on the heat exchanger tubes. Guess what? I am still getting build up on the tubes! All of the bases have been covered draft, wood M/C etc. I am thinking that the creosote is being deposited on the heat exchanger tubes during extended idling times of the unit. I do believe that I am oversized at the moment and that combined with burning beetle killed white spruce (very dry but lots of pitch) is causing the problem. I have photographed the air intake damper using time lapse photography at 1 minute intervals to try and determine how much idling time there is during the night.

I would like to correspond with someone on the forum who is burning clean during the night with no creosote build-up, on the heat exchanger tubes who is willing to do the same time lapse photography. We then can compare air intake cycle times and total percentage of open vs. dampened burn times. Any takers out there?

 

[antknee2]

Hi Doug
I think you hit the nail on the head ! If a Greenwood / Seton cycles into high limit damper closed position to often . The burning process is never fully up to high efficiency , with super heated refractory eating up almost all smoke gases . Or in idle mode the fire never fully extinguishes like with Fred Seton original design goal .
Doug would you be interested in data from my Seton boiler with Heat storage ?

 

[SteveJ]

Doug,

I just cleaned my HX and am planning a mixing valve installation this weekend. No storage but within the next two weeks...

Tell me how to rig my digital camera and I will collect the data?

Anthony,

I would like to see your data.

Looks like we have a Greenwood/Seton knowledge base data aquisition thread started.

Steve

 

[antknee2]

Hi Doug
Just wondering what camera interval timer settings you used for your research ?
Anthony

 

[DKerley]

Hello Steve & Anthony,

I used a sony camcorder set for still pictures. 1 minute intervals with a low resolution so that he memory card does not fill up. I am now experimenting with dumping heat continuously through my shop to compare damper times vs. creosote build up.

 

[bluecap24]

Doug,
I finally got my dad's greenwood 100 fired up Saturday night and wouldn't you know it the darn thing is dripping creosote! I installed the return temp protection, added the draft inducer, set all the load aqua stats to high temps to maintain the boiler temp and still dripping. I am burning good dry oak and hard maple. I think you are correct on the cycle times causing it. With this new building and all the correct plumbing it will maintain operating temps for quite a while and then when the damper opens it starts to bellow out black creosote smoke. Sorry I can't participate in the camera trials here, but will definitely be watching the thread.

Jim

 

[SteveJ]

Doug, Jim,

Please post all results you find on the damper intervals...

Also, please make sure that you do the "Anthony D" smoke test and seal to make sure there are no air leaks when idling:

https://www.hearth.com/econtent/index.php/forums/viewthread/11830/

My Seton W-130 was dripping creosote until I sealed all the air leaks - metal on metal just doe not cut it when idling...

Steve

 

[2.beans]

steve i posted pics on your last thread took me a couple of days but i figured it out.

 

[antknee2]

Hi Doug
I have not forgot about you . Need a little more time and colder weather .
Anthony

 

[DKerley]

Doug,
I finally got my dad's greenwood 100 fired up Saturday night and wouldn't you know it the darn thing is dripping creosote! I installed the return temp protection, added the draft inducer, set all the load aqua stats to high temps to maintain the boiler temp and still dripping. I am burning good dry oak and hard maple. I think you are correct on the cycle times causing it. With this new building and all the correct plumbing it will maintain operating temps for quite a while and then when the damper opens it starts to bellow out black creosote smoke. Sorry I can't participate in the camera trials here, but will definitely be watching the thread.

Jim

Hi Jim,

The Greenwood will drip moisture from the refractory for the first few days. Refer to the Greenwood manual as it mentions protecting your floor etc. I have just adjusted my damper aquastat to a 30 degree differential as opposed the factory setting of 15 so that the burn cycle is longer. initial observations are that the damper open time has doubled allowing a better burn but at the same time the closed time has increased as well.

 

[DKerley]

Doug, Jim,

Please post all results you find on the damper intervals...

Also, please make sure that you do the "Anthony D" smoke test and seal to make sure there are no air leaks when idling:

https://www.hearth.com/econtent/index.php/forums/viewthread/11830/

My Seton W-130 was dripping creosote until I sealed all the air leaks - metal on metal just doe not cut it when idling...

Steve

Hi Steve,

I'll post the data as soon as I collect enough to verify that it is accurate. After cleaning the greenwood this past summer, I sealed up all the panels etc. but have not done a leak check yet. My unit is oversized and I believe that is the main problem. I am experimenting with dumping heat out through my shop to increase the load and initially it appears to be working. The only down side to it is that I am not having that nice bed of coals in the a.m. like I did last year. Going to load the firebox with even more wood to see how it burns vs. duration.

 

[webbie]

Those pipes are ALWAYS cold in relation to the wood fire, even if they have 180 degree water running through them, so elimination of creosote on the pipes would seem to be very difficult. Hopefully, this is figured into the heat transfer calcs of the boiler design....the fact that the tubes run dirty.

 

[seymourwood]

looking for some installation info on my new greenwood 100... would any of you be willing to discuss? maybe some photos, instructions, any help will be appreciated.
there was very little info w/ unit, dealer is far away. so i thought i'd ask those who actually own these...so if anyone would care to respond. i will greatly apperciate any help i can get. as i'm just starting my install, my first question would be...do i need a draft inducing fan? my unit is in a detached garage, but i still don't want a garage full of smoke, so draft fan or no fan... ?
thank you for your time.

 

[SteveJ]

Doug,

Craig brings up a good issue about the cold pipes...

I was considering a setup like http://www.charmaster.com/creosote.html to bypass the cold down tubes relative to the heating load and fuel used.

Fred Seton told me that I would never get a clean burn with the small round (2-3") that I use in the shoulder season - too much surface area. However, the smaller rounds usually give a hotter burn - I will check the HX tubes again in about six months and report.

I also am in the final stages of the 600 gallon storage that I hope will help.

I do have a mixing valve on the return line and have it set to above 140. I shut off the hot feed and found the return water was varying widely from 70F to about 140F using straight return from the radiant floor and indirect water heater.

I too will try to monitor damper cycles and duration...

Hopefully, we can figure out these "simple" boilers!!

Steve