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Ricing up my woodstove?!

Posted: Wed Oct 05, 2011 12:56 am
by Jarod
Yep. Going to put a cold air intake on it. and upgrade the supercharger to a twin supercharger while I'm at it.
Thinking about adding NOS too...

But seriously, I've been doing some reading and found several pages: ... trofit.htm ... info/1677/

I don't think I want to install a cat into my furnace chimney but I'm thinking seriously about the cold air intake and also the secondary burn modifications.

My stove has been badly abused by the previous owner, nearly all the electronics (Wires, Wirenuts, thermostaty thingy) had been melted due to over firing and an improperly oriented draft inducer damper flapper thingy among other problems. Which compounded the overfiring because the blower motor wires got fried but the draft inducer motor wires had not, so the draft inducer ran until the stove was cranking out 600+ degrees on the chimney and over 300 degrees on the heat exchanger goober thing. (Measured with infrared thermometer, flue gases were quite likely much higher)

All of this together melted the cast iron grate for the ashes to fall through to the point it was no longer a grate but more of a rod.

I've fixed the electronics, re-manufactured the dampery thing so that it works now.
Last night I put 4 pieces of wood into it, the blower fan ran on and off from about 9pm to somewhere between 3 and 5 am. it kept the house at 65 all night, and its still holding around 60 now after the fire has been out all day.

I'm quite happy with that as that indicates I might be able to get away with far less than the ~20 face cord estimate I was given by the previous homeowners.

As you can tell I'm an absolute furnace expert, I know all the technical terms and proper names for components.

Re: Ricing up my woodstove?!

Posted: Fri Oct 07, 2011 3:44 am
by foxmiles
I've got a plan for you! see what you think

While stainless steel is by far the best material for a secondary burn system, Why not build a test system out of black iron?

Replace the baffle with 3x 1/2" black iron pipes connected at one end, capped on the other, 10 or so small holes drilled in each one, with 1" angle iron welded to the front and rear one to support a new baffle of firebrick?
the end would elbow down and out the bottom or low down on the side. Don't have a drawing app handy, so see if this makes sense (baffle only):

Firebrick |
Firebrick |

If it works well a stainless one could be built. I've got the stuff to cut and thread pipe, and weld together.

1. You want the gas exiting the chimney at 300*F to reduce creosote, though stove pipe temp is usually much lower that flue gas. I'm not sure you need a draft inducer at all, (maybe startup on a cold chimney) usually a 13ft+ chimney supplies sufficient draft for most stoves.
2. Cast Iron is almost impossible to melt (it will, but not like steel), it's awesome stuff, it will glow red-hot and still break instead of bend. Some grates are steel, cast is better (imo). You can weld up some steel ones in a pinch.
3. It's not cold yet.
4. From the Centers for Stuff I Heard From Some Guy: I've heard if your chimney is clean to start, running your flue up to 600 or so every morning for a few minutes will cause a little baby chimney fire to clean any creosote that built up in the last 24hr, though I'm a little nervous to try myself.
5. I'll see if this seems like such a good idea in the morning. (#4 is already pretty iffy)
6. I'll fire up inkscape in the morning and try to make some better diagrams.

Re: Ricing up my woodstove?!

Posted: Fri Oct 07, 2011 1:19 pm
by foxmiles
I think #4 would be OK with a stainless chimney, they are designed to withstand a chimney fire, if done frequently enough the risk of burning debris would be minimal. I wouldn't attempt this on a brick and mortar chimney.

Re: Ricing up my woodstove?!

Posted: Fri Oct 07, 2011 11:47 pm
by Tom
ok, so I ran another test fire last night since it was really cold.
I assumed everything would be perfectly fine if I just let it run automatically. wrong.

after about 15 minutes the face of the stove was over 1500 degrees and had swelled out about 1 inch. the chimney was around 550-600 degrees. the blower fan was running full bore and it does not push enough air to do anything useful.

the draft inducer fan was also running, inside the stove was an inferno.
I turned off the draft inducer manually (first thing I did was install a switch on that thing)

So what I'm thinking I can do is change it so the draft inducer turns off as soon as the blower motor turns on.
also possibly adding a higher cfm blower motor as the one that's on there is really wimpy, it doesn't even push the heat into the upstairs lol

I'll have to see better pictures or you show me what you're talking about lol.

Re: Ricing up my woodstove?!

Posted: Sat Oct 08, 2011 12:33 am
by foxmiles
See if this makes any more sense
Secondary air baffle replacement

Re: Ricing up my woodstove?!

Posted: Sat Oct 08, 2011 12:52 am
by foxmiles
I don't remember quite how the blower works, If it sends basement air upstairs you may need to leave the basement door ajar to allow return air flow. You want circulation, not to force the air out of the upstairs. At 1500* the air should flow without a fan...
1. Could need the bearings lubed too, usually it's 20 weight (atf should be ok too. Especially on old, dirty bearings).
2. On the draft inducer - that's way too hot, does it have a air supply flap? It should, adjust that to keep temperatures under control. try for little to no smoke outdoors and (surface) flue temp of 350-500*F (not quite sure where it should operate) 600+ is sufficient to start a chimney fire if there is creosote in it.
3. How much smoke do you get out the chimney? (just curious)
4. Be careful. At 900*f on the surface you could be over 2000*f inside and, depending on the thickness of the metal, melting the insides...
5. I don't know a lot about wood furnaces, my experience is mainly with stoves.
6. You may need a damper, and just turn off the draft inducer once the fire is going and see if that works.
7. You're not there yet, but sometimes you're better off buying a better stove. I fussed with my first one for 4 years of freezing cold nights (inside), a very smoky house, and glowing cast iron in the middle of the night before I gave up and bought my new stove. It's not perfect, but it's the exception rather than the rule that it's smoky or cold in here now.

Re: Ricing up my woodstove?!

Posted: Sat Oct 08, 2011 11:41 pm
by Tom
I'm not sure the bearings can be lubed, there's no spots for oil that I can see. It does pull air from the basement but I leave the door open anyway since the basement gets hot from the stove radiating heat.

The draft inducer has a supply flap that was broken, so I built a new one out of a coffee can, some sheet metal, a bolt and some wire.

I've never seen any smoke out the chimmney ever. And I just cleaned it so there's no creosote, or at least not much.

Yea, the temps worried me very much so I shut off the draft inducer and got the stove to cool down before I went to bed, I didn't want melting stoves in my basement lol.

Idk where I should put a damper in the system since its so goofy. Idk where the combustion air even comes from. Is there any chance you could bring your welder down when you come down here??

Yea id think about buying a stove or something but where would I put it and how big would it have to be to heat the whole house?