How often do you guys clean your heat exchangers?

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Brokenstone

Member
Jan 13, 2017
19
indiana
Its the secondary heat exchanger. I am on at least the 3 year plan.​
All fuel is below 20*/. Moisture.​
I should probably slow my blower down.​
My yukon is a newer one with stainless secondary exchanger.​
26 feet of class a chimney.​
No it doesnt plug that bad but i look at it once a month or so. Its really easy to do and i can open it up and look and have it back together in 10 minutes.​
20 if i decide to scrape the tubes and run the shop vac down them.​
I have never needed to clean the flue in over 10 years. Theres nothing there.​
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,405
NE Ohio
Its the secondary heat exchanger. I am on at least the 3 year plan.​
All fuel is below 20*/. Moisture.​
I should probably slow my blower down.​
My yukon is a newer one with stainless secondary exchanger.​
26 feet of class a chimney.​
No it doesnt plug that bad but i look at it once a month or so. Its really easy to do and i can open it up and look and have it back together in 10 minutes.​
20 if i decide to scrape the tubes and run the shop vac down them.​
I have never needed to clean the flue in over 10 years. Theres nothing there.​
How big is your house? You are getting drastically different results than I did...and I had 2-3 YO year wood back then too...more like 4-5 YO year wood now. I always wondered if someone with more heat load would have better results from a Husky....there was just no call for heat after the initial one...or maybe later in the day, but by then the wood was gone so...
 

Brokenstone

Member
Jan 13, 2017
19
indiana
It's difficult to run the husky until the temp gets down to 30f.
Running it for just a little heat is quite the balanceing act.
It got easier after i retired last year. It not a good thing for a husky to just sit and idile for a long time. I heat 2700 sq. Ft. 1100 of which is basement with bare concrete uninsolated walls. Rest of house is sprayfoamed.
House is all hardwood i sawed out of my land with a manual woodmizer lt40.

I burn about 3 cords a year.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,405
NE Ohio
It be true my friend. The Max Caddy is VERY prone to smoke roll in.
Huh...surprised to hear that...I assumed that the Max was just a larger version of the Caddy...and those don't have much issues with smoke rollout that I have heard of...and I didn't deal with it much on the Tundra either, which is same firebox design/setup.
All one needs to do is wipe the metal surfaces with anything and the flyash falls right off, but gaining assess 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.
Yes, I should have described better...the cleaning itself is easy, just flyash and some dry fluffy soot that comes off easily...its the access that is my issue. I have enlarged my HX access hole too (to match what the new VF100's have now) that helped some for sure, since I couldn't get my arm in much past my elbow before! ;lol
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
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 assess 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.


The only area I can't get to easily on mine is in the back where the tubes go vertical at the top of the firebox. I'm trying to figure out a brush system to get them. It will involve removing the vermiculite baffles at the top and a complete cooling down as I'd have to reach way into the back of the firebox to get them.
 

usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
Huh...surprised to hear that...I assumed that the Max was just a larger version of the Caddy...and those don't have much issues with smoke rollout that I have heard of...and I didn't deal with it much on the Tundra either, which is same firebox design/setup.

My situation could be exacerbated by the fact that my home is new construction which is quite tight. So, my basement has decent negative pressure... especially with a lot of make up air going up the chimney through my barometric damper. I'm learning that my situation isn't the norm on a lot of fronts...
 

woodey

Burning Hunk
Feb 8, 2018
206
ST. Lawrence Valley N.Y.
I clean the HX on my Kuuma about half way though the heating season . Will have to get at it tomorrow as it will be in the lower 30’s and then daytime highs in single digits and nights a few degrees below zero. I’m with you Brenn on the idea of a better gadget to clean the HX. I have a nephew on the farm who has a nicely equipped machine shop and can build just about anything if I could only come up with a decent design for one.
 
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brenndatomu

Minister of Fire
Aug 21, 2013
6,405
NE Ohio
I’m with you Brenn on the idea of a better gadget to clean the HX.
Here is what I made...nothing fancy...just cobbled together in a few minutes...3x5" (ish) piece of 18 GA metal with a 1/4 x 3/4" slot cut in the middle. 1/4" steel rod for a handle, inserted into the slot at a steep angle and welded in place...I wish I had made the handle longer though...like 36" instead of 28".
The steep angle of the blade allows you to turn it on its side to get between the HX tubes, and also behind...can scrape the backside of the tubes and HX ceiling too...just flip the blade over once its behind the tubes, the angle allows you to get right up to the ceiling and down to the back wall (including the back wall...but that is a little cumbersome...would be better with that longer handle I mentioned)
The other things I've tried was my Sooteater brush...works ok, but kinda messy and hard to control precisely...barely fits between the tubes also.
You can also wipe down the upper parts of the tubes with a Scotchbrite pad if you don't mind sticking your arm clear in there...like I said, can only get part of it though...and you have to be part contortionist.
I really hardly use the scraper that comes with the VF at all since I made my own.
Here's some poor pics.
IMG_20210121_180406945.jpg laying on its back
IMG_20210121_180439668.jpg laying on its side
IMG_20210121_180522838.jpg laying on its face
 
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woodey

Burning Hunk
Feb 8, 2018
206
ST. Lawrence Valley N.Y.
Here is what I made...nothing fancy...just cobbled together in a few minutes...3x5" (ish) piece of 18 GA metal with a 1/4 x 3/4" slot cut in the middle. 1/4" steel rod for a handle, inserted into the slot at a steep angle and welded in place...I wish I had made the handle longer though...like 36" instead of 28".
The steep angle of the blade allows you to turn it on its side to get between the HX tubes, and also behind...can scrape the backside of the tubes and HX ceiling too...just flip the blade over once its behind the tubes, the angle allows you to get right up to the ceiling and down to the back wall (including the back wall...but that is a little cumbersome...would be better with that longer handle I mentioned)
The other things I've tried was my Sooteater brush...works ok, but kinda messy and hard to control precisely...barely fits between the tubes also.
You can also wipe down the upper parts of the tubes with a Scotchbrite pad if you don't mind sticking your arm clear in there...like I said, can only get part of it though...and you have to be part contortionist.
I really hardly use the scraper that comes with the VF at all since I made my own.
Here's some poor pics.
View attachment 272461 laying on its back
View attachment 272462 laying on its side
View attachment 272464 laying on its face
Looks good. Do ya think if I got the torches and cut the access opening larger it could mess with the warranty?;lol
 
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brenndatomu

Minister of Fire
Aug 21, 2013
6,405
NE Ohio
Looks good. Do ya think if I got the torches and cut the access opening larger it could mess with the warranty?
I did very carefully open mine up a bit using a 4" angle grinder/cutoff wheel...took 3/4" more off the bottom (IIRC) whichever side had all the extra overlap from the cover...turns out they started doing this on the new ones now...I never could understand why the cover was so much bigger than the hole, and the hole not "centered" top to bottom...sounds like they are now though.
 
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Wood1Dennis

Burning Hunk
Jan 17, 2016
144
Eastern Wisconsin
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 have a Caddy, I very seldom have smoke roll in. It has happened on really damp warm days when the draft seems weak. I'm surprised that you have a problem.
I just cleaned my HX, for only the second time this season. Some build up, but not bad. Not enough to hurt the draft, but it is so easy to do I like to clean it out from time to time.
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,689
Wisconsin Dells, WI
I just cleaned my HX, for only the second time this season. Some build up, but not bad. Not enough to hurt the draft, but it is so easy to do I like to clean it out from time to time.

For how easy you guys have it on those SBI units...I think I'd be cleaning it weekly. Wouldn't hurt anything. Doesn't take much flyash to insulate and reduce heat transfer.
 
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Wood1Dennis

Burning Hunk
Jan 17, 2016
144
Eastern Wisconsin
For how easy you guys have it on those SBI units...I think I'd be cleaning it weekly. Wouldn't hurt anything. Doesn't take much flyash to insulate and reduce heat transfer.
JR, I think that was one of the selling points on my furnace. My parents had an old 1980 vintage Russel Stove furnace. It was an early and not very effective attempt at a gasifier furnace and it had a heat exchanger that routed the smoke up, forward, around both sides and back out the back. The only way to clean that thing was to push a vacuum cleaner hose in from the fire box end and from the stovepipe end. And I would reach up there as far as I could with my arm. Even then, I think there were parts I never did reach! Had an old pair of coveralls I hung in the basement just for the job. They were permanently black with creosote and ash. My gosh, it was a miserable job. Did it twice a year.
 
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usernametaken

Burning Hunk
Nov 25, 2017
142
Western, MA
As I said previously, my install is not typical. I do have negative pressure in my basement being that I'm new construction and the house is very tight. So, is a contributing factor. I have walk out doors about 5 feet from the furnace and if I open one of them wide, there is less smoke. However, I'm not going to bother with that each time I load so I've learned to load quickly and not put anything like paper birch at the bottom on the coals because it will smoke almost instantly. All that said, I'll revise my comment to say that MY Max Caddy is very prone to smoke roll in and when I get ash build up in the tubes, it increases. I've learned from being on these forums that there is no common ground between wood furnace installs. The same unit can be in a lot of different homes and act differently to some extent in each. Sure, there will always be two guys who say, "Me too" and have the identical results. However, one off issues are possible as well with all the variables that can effect a wood appliance install...

PS: JR, I agree on the frequency of cleaning. I'm not going to once a week religiously. But, I'll sure be doing more often than once ever 1.5 months like I did before...
 
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