Of Clogged Combustors and Wood Stoves

Published by: Nick Meissner

Okay, so I have a confession to make...

2016 was a crazy year in our lives and last fall I was so pushed for time that I was late in getting my firewood in. So late that some of it wasn’t totally cured and much of it got soaked by the rain. 🙁  Kind of a bad spot to be in with winter approaching! Not to mention that it's hard on our stove combustor.

I tried to compensate by splitting the wood smaller and burning hot fires, but it caught up with me. The catalytic combustor in my stove, which was already getting old, didn’t take very kindly to this sub-par wood.

In fact, it decided to clog up. It would simply put out the fire if I turned it on, so I was left with burning combustor-less, which works but is not as efficient.

The Downsides To A Combustor

It is not uncommon for a catalytic combustor to need replacement every 5-10 years (yours may vary). I was expecting this, but it caught us at a bad time.  In December we had the longest stretch of arctic weather I ever remember seeing. It was over a month without breaking 30°F and most of it far below that.  So I didn’t really want to cool the stove off and change it out right then.

In addition, they are not cheap.  For my stove it would cost in the neighborhood of $200-$300.

How I Unclogged My Combustor

However, I discovered something this winter and I’ll pass this on in case you find it helpful. I have noticed this little trick work in the past, but this winter it was a lifesaver.

If I am naughty and clog my combustor up, I can often clean it out by simply burning really hot fires for a few days.  I’ll leave the combustor off and get the stove hot enough so the stove thermometer is near the upper end of the safe zone.  I’ll let it burn there for a while and then turn the combustor on.  Likely the temperature will start falling soon.  Once the temperature gets back down to the middle of the safe zone, I’ll take the combustor off again and let the fire flare up, repeating this cycle as often as possible for a few days.

It works much better to do this during a cold snap, or else you’ll be opening up windows all day (which isn’t a bad thing).

After several days of this, I usually find that my combustor is working much better.  Maybe not back to normal, but much better than it was.

When the weather warms up this spring I will probably take the time to clean it. Be sure to follow the manufacturers instructions when you clean your stove, as it’s a fairly involved process.  If the thorough cleaning doesn’t do the trick, then we’ll purchase a new one.  And hey, that wouldn’t be a bad thing to have around as a spare, would it?

Why Not Combustor-less Stove?

All of this may bring up the question—why not just get a stove that doesn’t have a catalytic combustor?  You certainly could, and I totally understand why.  But for the sake of discussion, I’ll mention a few reasons why many folks prefer one with.

First, thanks to EPA regulations, I’m not aware of very many combustor-less stoves available.  Not very many at all.  There may be more, but Vermont Castings is the only brand that comes to my mind that make a few combustor-less stoves.

An added advantage to having a combustor is that your burn times are typically longer.

Lastly, I like the amazing job that a good combustor does.  It reduces the particulate in your smoke. How it does that is by re-burning the smoke that would ordinarily go straight up the stovepipe.  That means more BTU’s from your stove.

Just to illustrate the efficiency of our stove, I have gone over a YEAR without cleaning my ashes out!  Mind you, we live in a climate where we have a fire burning continuously for close to 6-8 months and intermittently for another 2-4 months.  That is phenomenal, as it shows how little of that wood is left once the stove is all done with it.  5 cords of wood in the bottom of one stove!

What If The Combustor Bites The Dust?

If your combustor (or mine) is beyond repair and you are not able come up with a new one anytime soon, all is not lost!

As long as your stove is a good one, it should be very air tight and should function just fine without it.  Yes, it will plow through more wood than normal.  Yes, you will notice a shorter burn time.  But it will work and it should keep your home warm.

And that’s why I don't worry about using a stove with a combustor in it.


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