How often do you guys clean your heat exchangers?

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usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
I've found that when I go over a month without cleaning, my blower never kicks up from speed 1. This tells me that the ash in the tubes is insulating them to the point that some of my heat is going up the chimney instead of into my plenum. So, I was just wondering how often other brands needed cleaning to keep things working at their full potential.

On another note, I never seem to get that shiny hard creosote but rather a coating of powder like ash. It's so fine it's like baking flour and comes off with no pressure at all. I'm burning mostly very dry red maple and white birch that was down and split a few years back when our lot was cleared. I'm wondering if different woods throw more fly ash (if that's what this is as opposed to a different kind of creosote?) than others kind of like how different woods coal differently? I have some black birch and red oak mixed in but not a large enough supply this year to do a month long test.

Thoughts?
 

andym

Feeling the Heat
Feb 6, 2020
434
Hicksville, Ohio
I've found that when I go over a month without cleaning, my blower never kicks up from speed 1. This tells me that the ash in the tubes is insulating them to the point that some of my heat is going up the chimney instead of into my plenum. So, I was just wondering how often other brands needed cleaning to keep things working at their full potential.

On another note, I never seem to get that shiny hard creosote but rather a coating of powder like ash. It's so fine it's like baking flour and comes off with no pressure at all. I'm burning mostly very dry red maple and white birch that was down and split a few years back when our lot was cleared. I'm wondering if different woods throw more fly ash (if that's what this is as opposed to a different kind of creosote?) than others kind of like how different woods coal differently? I have some black birch and red oak mixed in but not a large enough supply this year to do a month long test.

Thoughts?
I like to clean mine every week or so if I get the chance. I haven't run it long enough to really get to know when it needs it. I too get a fair amount of black sooty powder. Comes right off though as you mentioned.
 
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usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Yup, I use the half round tool that came with the furnace and it all comes off first pass with no pressure at all. I pull it all forward and vac it all out with the ash vac. Takes a couple minutes tops. I think I might start doing it a little more frequently to keep things optimal.
 

3fordasho

Minister of Fire
Jul 20, 2007
1,004
South Central Minnesota
When I was runnning my Tundra - I'd clean the tubes every couple months but it probably should have been more frequent. Once a week seems a little overkill but maybe once every two weeks or for sure monthly.
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
To be honest, I never realized how big of an impact it made in heat output and wood usage. Last year I only did it a couple of times and it was another part of my poor output. This year I went 1.5 months the first couple times and am just now realizing the impact of how it insulates the exchangers. When clean, the blower cycles on and off even when I'm down to a few red coals on warmer days. When they are dirty, I can't get the blower above speed 1 no matter how hot the fire and am loading more wood more frequently to keep the blower going on warmer days. I'm thinking it's now a 1 month tops routine.
 

3fordasho

Minister of Fire
Jul 20, 2007
1,004
South Central Minnesota
To be honest, I never realized how big of an impact it made in heat output and wood usage. Last year I only did it a couple of times and it was another part of my poor output. This year I went 1.5 months the first couple times and am just now realizing the impact of how it insulates the exchangers. When clean, the blower cycles on and off even when I'm down to a few red coals on warmer days. When they are dirty, I can't get the blower above speed 1 no matter how hot the fire and am loading more wood more frequently to keep the blower going on warmer days. I'm thinking it's now a 1 month tops routine.


The fly ash that builds up is a good insulator. I'm not running the tundra anymore but have the same issue in my gasification boiler, that has 7 x 2.5" heat exchanger tubes that build up a coating of really light grey fly ash, lighter and dustier than what would build up in the Tundra's HX tubes. I've been cleaning the boiler HX tubes every Sunday at it really helps keep the output consistent. Fortunately the HX tubes are almost as easy to get to as the Tundra's and a tube brush does the job perfectly.
 
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trx250r87

Burning Hunk
Nov 30, 2012
169
NE Wisconsin
I did every 2-3 weeks on Tundra and the same now with Heat Commander. I knock off the flaky/powdery buildup with the supplied tool and vacuum it out with a shop vac. Takes about 5 minutes.

Eric
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Thanks Eric. Sounds like I'm on the right track then...
 
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peakbagger

Minister of Fire
Jul 11, 2008
6,486
Northern NH
Dry ash is not creosote. All the carbon is burned out and it just left over in-organics. There is such a thing as ash fusion where the ash starts to stick to surfaces and to itself. Yes it does insulate the tubes but its lot easier to handle then creosote. It means you are doing a good job.
 

sloeffle

Minister of Fire
Mar 1, 2012
854
Central Ohio
Have a PSG Caddy, so the firebox design is similar yours. I try to clean mine as ”often as possible“. I’ve done it at 3 days ( probably overkill ) to about two weeks max. A lot depends on the weather.
 
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usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Interesting reports guys. Thanks for the thoughts....
 

laynes69

Minister of Fire
Oct 2, 2006
2,600
Ashland OH
I clean mine (caddy) when I think about it. Usually once a week or so and it takes about a minute to open, scrape and remove. I do try to clean it when it gets really cold and I need maximum heat exchange.
 
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CaperM

Member
Dec 31, 2013
28
Nova Scotia
My old Jetstream boiler tubes needed to be cleaned once a month and the Vedolux 37 is running about the same.It takes about 5 minutes for the Vedolux.When the exhaust pipe thermometer starts reading above 250c.it time to run the brush through.My wood is mostly sugar maple,rock maple yellow birch and ash,all been cut and split for1-2 years.
 

Gearhead660

Minister of Fire
Dec 20, 2018
692
Southern WI
Tundra 2, clean after 2-3 weeks, black powdery build up.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,404
NE Ohio
When I had the Tundra 1 furnace, I got in the habit of doing a HX cleaning every week...if you monitor your flue and plenum temps like I do, it makes a very noticeable difference...and its so quick n easy on the SBI furnace design, why not?!
I just cleaned the HX on the Kuuma VF100 yesterday...and that brings up one of my complaints on the VF, after being used to how easy it is to clean the SBI style HX, cleaning the VF HX kinda stinks...not the worst, but it sure could be easier...it just takes some time to get all the nooks and crannies, although I probably went overkill with it for just a mid season cleaning, but it really makes a big difference...flue temps are back down at least 50*, and plenum temps up 3-5*...house was warmer when I got up this morning than what I was used to here recently too.
I have made some special tools to facilitate cleaning, but its still too time consuming IMO, (anybody with a VF that has come up with a slick system, let me know!) I had about 1.5 hours in it, although like I said, it could be done quicker I'm sure...but the last two winters I have only done one mid season cleaning (January) and then a full cleaning soon after the end of the heating season.
Not sure if OP was wanting to hear from all us furnace guys or not, since he has a boiler? ==c
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
I'm the OP and no boiler here LOL.
 
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brenndatomu

Minister of Fire
Aug 21, 2013
6,404
NE Ohio
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usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Everyone has to make their first mistake eventually. Took you a while but you got there.... ;);lol;lol
 
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Brokenstone

Member
Jan 13, 2017
19
indiana
Once a month on my Yukon Eagle/Husky.
It doesent always need it.
One sure sign it does is open up the combustion chamber door and it smokes-it needs cleaning.
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Interesting thoughts on the smoke roll in issue. Now that you mention it, I notice more of it right before a cleaning too...
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,404
NE Ohio
Once a month on my Yukon Eagle/Husky.
It doesent always need it.
One sure sign it does is open up the combustion chamber door and it smokes-it needs cleaning.
What is your definition of "need it"?
I agree with the smoke rollout when the HX is almost plugged...but if that's the case, it "needed it" long before that. One of the biggest reasons mine went buh bye...was too "needy"
Interesting thoughts on the smoke roll in issue. Now that you mention it, I notice more of it right before a cleaning too...
I would be shocked if your HX is actually plugged up enough to cause this issue...if that's the case you have some wet wood brother! ;)
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
It be true my friend. The Max Caddy is VERY prone to smoke roll in. Early season it seems great but after a month or so I need to load faster and faster to avoid it. I never put it together before as you don't notice when things are going right but you perk up when they aren't. It's back to good after a good scraping though... IE: now since I just did it again a couple days ago. The day before I was off to the races every time I loaded. Now I have a good 20 seconds before the coals get the wood to start smoking enough to cause roll in... Same wood, same draft, no other variables. As to wet wood, I sure don't. 3 year old red maple mostly that's about 7% on a fresh split. To quote one of my favorite lines from The Natural, "It's as dry as your granddaddy's skull!" LOL Joking aside, the Caddy is so prone to roll in, I NEVER load white birch, paper side down directly over coals as it will ignite too fast and there is no way to win that race...
 
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JRHAWK9

Minister of Fire
Jan 8, 2014
1,689
Wisconsin Dells, WI
and that brings up one of my complaints on the VF, after being used to how easy it is to clean the SBI style HX, cleaning the VF HX kinda stinks...not the worst, but it sure could be easier.

I will second that after watching a video of how easy it is on the SBI stuff. After I'm done cleaning my VF100 I look like I am part negro.....above the waist that is. ;lol All one needs to do is wipe the metal surfaces with anything and the flyash falls right off, but gaining access to all the surface area is what is the pain as Bren mentioned above. The HX area is a rather large area with metal tubes running through it at an angle, creating some nooks and crannys.
 
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