Tarm Boiler: Ash in Flue Pipe

I agree-- in my opinion, this is one of the few real nuisances of a gasification boiler - partly because this ash is so fine that it's hard to clean it out without having it become airborne and spreading around.

I think I recall that the Wood Gun has a cyclone separator on its outlet, which I assume is to remove/ accumulate ash.

In concept, you could perhaps add something like that to another unit, but it seems like it would be bulky/ heavy to mount on a flue pipe.

Alternatively, you could have a large chamber after the boiler and before the main run to the flue-- drop the velocity, allowing the ash to fall out of the vapor stream. However, that might adversely affect draft (not sure). Or maybe a "vertical trombone" (almost like a trap under a sink) with a cleanout hatch (again, adding bends may adversely affect draft).

I'll be interested to hear what peoples' ideas are on this.

is anyone using a 'base tee' for this kind of ash trap? Instead of using a 90* elbow at the back of the boiler, install a tee with one end pointing straight down with a cap on it. This should allow a lot of fly ash that would otherwise settle in the elbow to settle in the bottom of this tee arrangement and be easily cleaned out by removing the cap. Like this "-l"

Alternately, if there is a long-ish horizontal run before the chimney turns upward, put the tee in so that one end points straight through the 90 - again with a cap on it. This way you can remove the cap and use a brush or ash vac to clean out the horizontal run. Like this "_l_"

sorry for the "artwork"!

Chris

Tarm and ash. Wouldn't trade the Tarm because of the ash. Love the unit easy to operate etc.
But while we are on this subject... I know it's not recommended to remove the lower refractory to clean out the ash from below the tubes. Does any one have any tricks to clean out the way back under the fire tubes ? I just cleaned mine by sticking a shop-vac down the fire tubes. That doesn't really clean area out well, and the refractory is in the middle you can't rake much ash forward either.

I burn dry pine almost exclusively and never have regarded the ash as a problem or safety hazard. My stack takes a 90 off the back of the Tarm and then vertical, first with 8' of single wall black stove pipe then Class A for 11'. When I brush the hx tubes, which I do every 2-3 weeks, I also scrape the walls of the smoke box and use my shop vac to vacuum out the smoke box, and I shove the hose into the 90 from inside the smoke box to suck out whatever ash has settled. Works well. I brush the stack only once per year at the end of the heating season, and never more than maybe a 1/8" coating of ash in the stack, no creosote or other hard deposits. I am a surprised by comments on large quantities of ash, something I never have experienced.

Tarm Sales Guy said:

is anyone using a 'base tee' for this kind of ash trap? Instead of using a 90* elbow at the back of the boiler, install a tee with one end pointing straight down with a cap on it. This should allow a lot of fly ash that would otherwise settle in the elbow to settle in the bottom of this tee arrangement and be easily cleaned out by removing the cap. Like this "-l"

Alternately, if there is a long-ish horizontal run before the chimney turns upward, put the tee in so that one end points straight through the 90 - again with a cap on it. This way you can remove the cap and use a brush or ash vac to clean out the horizontal run. Like this "_l_"

sorry for the "artwork"!

Chris

Click to expand...

I have EKO 40 but same T like you describe. I can take off the plug on the bottom and clean out most of the fly ash using my hand and a garbage bag in the horizontal flue pipe going to the boiler. Since it is loose it works pretty well using only hand.

[quote author="Tarm Sales Guy" date="1290551727"i... if there is a long-ish horizontal run before the chimney turns upward, put the tee in so that one end points straight through the 90 - again with a cap on it. This way you can remove the cap and use a brush or ash vac to clean out the horizontal run. Like this "_l_"
Chris[/quote]

That's how I've got it, since I could not avoid the horizontal run between where my boiler fits and where my masonry chimney is. I had an elbow the first season, and after discovering the rather amazing amount of ash in the pipe, switched to the tee with cap. My flue run from boiler to chimney is far from ideal (due to old house basement factors)- about 12 feet with 3 turns [I know that both the length and turns are to be avoided whenever possible, but I could not avoid them- thankfully, I was able to get upward pitch the whole way, and my masonry chimney has excellent draft, which makes it all work) (all of the turns are now tees with caps to allow inspection and cleanout).

I accept that the cleanout tee works, but it would be great if there were some feasible "ash trap" so that I didn't have to clean out the long horizontal run.

Do you clean out the ash from the bottom of the boiler every day when you load it?

I clean out bottom front, sides and refractory every burn. I have turbulators installed in the fire tubes maybe that's why my ash doesn't get to the top and into the flue pipe. I do get some ash up top but not much.

Squeezle Bob said:

Do you clean out the ash from the bottom of the boiler every day when you load it?

Click to expand...

Not in the past, but I am this year, in hopes that it'll lead to less in the flue pipe.

RobC - good point on the possibility of the turbulators preventing/reducing ash up the stack. They do slow down the velocity of the flue gasses, and that may reduce the fly ash into the stack. I have the homemade chain turbulators, and I do get ash on top of the smoke box but very little beyond that.

Occasionally, when I notice an ash buildup (there always will be some ash, which is of no concern) but not every burn, I rake out ash from the gasification chamber with the rake supplied by Tarm. I modified this rake by tack welding a semi-circular piece of steel on one side that has the curvature of the gasification tunnel, and also occasionally I will rake any accumulated ash from the tunnel if it doesn't seem to blow clear during a burn. I think a small quantity of ash in this area provides some protection for the refractory.

This may not cover the original question about ash in the flue pipe, but it is related to the cleaning process, so I'll chime in:

After years of using my "official' Tarm fire tube cleaning brush, it dawned on me that there must be an easier & more effective way of getting the "scaly" stuff off the sides. The answer for me was a cheap 3" hole saw (because I'm not using it to cut steel), along with 2 extension rods. I did modify the connection from the hole saw to the extension rod, as the small allen screw wasn't rugged enough. Plus I added a "spacer" of sorts to better match the my cleaning rig to the ID of my tubes. I use a 1/2 HP drill to run it, and find that it cuts my cleaning time down to a fraction of what it was, and I get a much cleaner tube. I'll post photos of my setup for anyone who might be interested.

I have the Tarm "turbulators" in my oil-burner-side fire tubes, but haven't thought of trying them on the wood burner side. I would think they would plug things up a lot quicker. I also suffer from a lot of ash buildup in my section of flue pipe between the boiler and chimney, and like the idea of using tees and cleanout caps. Thanks for that tip!

Works well. A post sometime ago did the same think with a cup wire brush. Here are some pics of my tubes after a full month of burning pine. Very little ash. Also shown are the chain turbulators in place.

Jim, Your turbulators sure look good - I'll have to give them a try! My "oil side" turbulators are getting pretty well burned up after a couple of decades of oil burning, and I was wondering how to replace them - looks like the chains would work well on that side as well.

Since I'm doling out advice as well as getting some, here are my notes about using a wet/dry vac to help clean up ash:

[First, a disclaimer: Don't take any advice that would potentially cause fire or damage to your home - check with your local fire department before doing anything that might put you or your family in harm's way.]

*I use my Craftsman 2HP 16 Gal unit (bought in 1984 and still going strong!) when cleaning the boiler, BUT I would caution anyone to make sure there are no live embers in the ash when doing this. I failed to do that once when cleaning out oil soot (long story), and didn't realize it until the paper filter started to smolder. Nothing like black oily soot spread all around the basement (and one less-than-pleased wife) to drive home a little common sense!

*Along with the paper filter / live embers issue, keep in mind that the plastic hose will melt on you if things get too hot. I have replaced my hose just once in 26 years (and not because I melted it), so you should be okay if you keep an eye on things.

*If I had cleanouts on my flue pipe, I think I could get a fairly thorough cleaning using the wet/dry vac without disconnecting the entire pipe. The hose will snake through the elbows fairly well, and by gently banging on the sides of the pipe, you will knock the more stubborn stuff off & directly into the vacuum hose. But don't just assume it's all good when the ash stops flowing - verify that all is clear. I have used a basic inspection mirror for this in the past (available at auto parts stores), but I found an even better way the last time: digital camera. With the light the flash provides, you'll get a much better look inside the pipe, and if it takes 10 attempts to get a good photo, who cares? I'll attach a "before cleaning" photo I took. You'll see the cutout for my barometric damper on the left (something I must deal with using my single outlet flue on my 2 fuel Tarm).