Small Hopper Fire

Hi,

I have an Alaska Channing 3 stove. It is a bottom exhaust with direct vent. I installed a baro before the direct vent about 2 years ago to prevent hopper fires. The stove also has an outside fresh air pipe for combustion. Anyway, I came home the other day and smelled something like paint burning. I checked the stove and I could see the fire was moving up the grate. I immediately shut down the stove. From there I scooped out all the coal and saw that the fire was on the paddle which is at the bottom of the hopper. I cleaned out the coal around the paddle and off the grate and used the shop vac to vaccum out the holes in the grate and the flyash inside the stove. I stuck the hose into the direct vent to get as much out as I could. Then I took compressed air and blew out the outside shroud where the exhausts leaves the house. I didn't fully clean the exhaust line though. I figured I only had about a month to get through before I did my end of year cleaning.

Anyway, what would cause the fire to move up the grate? I woke up this morning after I thought the stove was fixed and the hopper was super hot and the fire was right over the paddle at the bottom of the hopper again. I'm going to re-seat the grate and do a full cleaning but what would cause this? I have a barometric dampner and the draft guage reads .03-.05. which is where it always is. Whay should I check?

Also, right aftere I cleaned out the hopper I tried the paddle and it was making noises and wasn't running right away on test mode. Then I waited 5 minutes and tried it again and it was working. Any advice is appreciated. Thanks in advance.

It could be a draft problem, but, Did you clean out UNDER the grates, ALSO, check ALL your gaskets around the grates, hopper, blower plate, etc....you might have an air leak, was your coal LOW in the hopper? Sometimes that will cause it to pull air thru the hopper.

if it's idling a lot, maybe turn the draft down a bit on the DV, to like .02, probably pulling too much air thru the hoopper, causing the fire to burn back.

traderfjp wrote:Hi,

I have an Alaska Channing 3 stove. It is a bottom exhaust with direct vent. I installed a baro before the direct vent about 2 years ago to prevent hopper fires.

Hopper fire has nothing to do with a direct vent or a baro !

Take a look here , it explains it all :

Hopper Fire - Alaska Channing 3 with direct vent

Not all hopper fires have to do with baro or draft settings, but a great many do, especially on Alaska's since they do not provide rheostats or baro dampers with their mechanical venters.

Where are you measuring draft? Hole before the baro damper? Hole in the stove body? Are you sure any internal air channels are clear? If you measure draft at the baro and there is an internal clog, it will still read a reasonable draft but in fact not be inside the burn chamber. In that situation, the combustion air ends up being forced out through the guts of the stoker assembly and up through the hopper, leading to the back burn.

Assuming everything is clear, make sure the back of the grate is sealed up either with a strip of rope gasket like they do on Leisure Lines or with furnace cement as Georgie recommends in the thread he linked to. If that seal isn't good, coupled with the extended idling times you've likely had recently with the warmer temps, you could have developed some fire creep back that you were avoiding earlier in the season.

Make sure the grate holes are clear too. If a significant number get clogged up it can force more air to leak out of a marginal seal, resulting in the same kind of problem.

Thanks for all the replies. I pulled the grate and the silicone I used to seal the back of the grate had failed, as suggested by some of the great replies. This time I ordered the rope seal from Alaska and will do the re-install the right way. I got less then a season with the high temp silicone. While they were shipping anyway I also ordered gaskets for the doors, and hopper. Total cost 43.00.

traderfjp wrote: I also ordered gaskets for the doors, and hopper.

Good idea IMO. Your going to have it shut down and torn apart anyway, might as well go the extra mile. Also as someone else said, that is peace of mind come next season.

Should I use silicone along with the casket on the back of the grate or install it as the factory would?

I would use regular furnace cement, it is good for 2000*, the high temp silicone is only good for 4-500*. A small tub or tube of furnace cement is only about $3-4. And it really sticks well to clean steel and cast iron.

Greg L

Sounds good. I need to take off the grate twice a year for cleaning. WIll the furnace cement be a pin to remove and destroy the gasket or is it easy to remove?

Thanks

I've never had to use furnace cement on my Alaska kodiak's grate in all the years I've had it. After the season is over I completely disassemble the stove, clean it - making sure all the grate holes are open and the fines are emptied from under the grate, and check all the gaskets. I pay very close attention to the gasket at the back of the grate with the strip of metal in it (hardback gasket?). It is here, I believe, that a hopper fire problem can occur if this gasket is missing or worn.

I'm not telling anyone not to use furnace cement but I believe that if you use the proper gaskets in good shape you can save yourself the extra time and mess of having to apply, then remove the furnace cement every time you service the stove.

traderfjp, how do you remove the grate from your Channing iii, I have one with a powervent that is in it's second season and I will have to give it a good cleaning at the end of this season. I was wondering how to remove the grate to clean all the fines, I thought I had to remove the feed mechanism from the back of the stove to remove the grate. Thanks.

The easiest way yo do it, is to have a nice guy like me stop by, since I do it for no charge, I own a place in Gouldsboro, and the next time I am going there, I can make arrangements, especially if you let me give you my SHPIEL about my CoalPilot.

If you insist on not talking to strangers, you may click the link above under my previous posting, and the pictures are self explanatory, if you still hesitate to move the grate out, you may be able to have it totally cleaned, if you remove the mechanism from the back, and insert a narrow tube hooked up to a vacuum cleaner, ( very similar to the way a Gynocologist can rebuilt an entire engine of a car through the muffler )

The grate simply lifts off. You might have to use a rubber mallet to get the grate back on. The bottom of the grate is grooved with a gasket and a gasket at the back of the grate. It's real easy to damage these gaskets if you aren't careful taking it off and on.

I completely disassembled my Channing III last spring and after removing the combustion blower (1 bolt), and the convection blower (just to open up the back), and the hopper (2 bolts), it was 4 bolts into the back of the stove and the entire combustion casting came out of the stove. It was suprisingly heavy (40 pounds or so).

I'll do the same thing this year. I'll probably replace all the rope gaskets as well, including those that mount the combustion casting to the back of the stove.

I don't plan on using furnace cement for anything on the stove...

Thanks for all the info on the Channing iii, I think that between the pictures and the advice on how to remove the grate and taking motors off I should be able to give a better cleaning this spring.