Need advice, shut down this morning.

I have an Alasksa Channing 3, bottom vent, power venter (with manometer). When I got home this morning Co detector was going off in basement. When I went down to check it out, smelled sulpher and the Co ppms were high. Everything looked good at stove, had a good draft (-.5) feeder system seemed fine, temperature on stove was 300 degrees (where I left it). Then I took the lid off hopper and the top of the coal was soaking wet? and this is where the strong smell of sulphor was comming. I dug into coal and it was warm and did see a little smoke. I immediately shut stove down and ventilated basement.
Well, I am thinking it is a gasket that has failed and allowed air and heat up into hopper.? I know there are diffent gaskets (strongback,grate gasket 2' x channel gasket and feeder housing rope gasket. Also hopper gasket. (I am reading from manual)
This stove is in its 6th year of operation without a single problem. I did feel gaskets at start of year and seemed soft (ok). Any ideas of what gasket failed?

Just guessing without knowledge of your stove. Combustion is regulated by a fan which if draft is not adequate to exhaust those products of combustion will create positive pressure in the fire chamber. The hopper is the easiest path to relieve that pressure and the wet coal is from condensation of the flue gas. I would suspect fly ash is blocking the normal flue gas exit.
Measuring draft over the fire would confirm this. I think this is the best place to measure draft with any stove since it is the place where it really counts and especially with a stoker which is capable of creating that positive pressure in the fire chamber. Drill and tap for 1/4 inch hole in the door and hold a match to it and you will quickly see if the flame pulls in, which it should. Block the hole with a 1/4 x twenty screw when done.

Inspect the entire flue gas path within the stove since it seems obvious to me that draft is positive within the stove. Any leaking gasket normally should have air going in and not out unless that gasket is so bad that it is consuming most of the draft.

If the draft is -0.5 you are way high. The draft should be >-0.04. Even -0.05 is a bit high. If you over draft an Alaska you will have a fire in your hopper. If the firing rate is low and the draft is high it is almost a guarantee. BTDT.

Thanks guys, I meant to say the draft was at -.05. I do have a variable speed power venter, and had cut the speed back a couple years ago ,but the manometer looked ok. But I do understand that positive pressure could be the issue? I will do a total cleaning tommorow aand see if there is a blockage somewhere.

And make sure you calibrate your manometer, unhook it and ZERO it out, sometimes it can get out of calibration. Maybe turn the draft down to -.03-.04 as not to pull to much draft.

Sometimes if you have too much draft, it will pull the air thru the hopper and make it burn back on the grates,
Typically, a gasket leak on/around the grates can cause it to burn back on the grate and cause it to come up thru the hopper.

I would check everything.

The copper tubing that goes into my stove pipe (to my manmometer) (before the baro) is not air tight into the pipe. Could this be giving me a false reading?

Lee1 wrote:The copper tubing that goes into my stove pipe (to my manmometer) (before the baro) is not air tight into the pipe. Could this be giving me a false reading?

No, I do not think so.

Thanks for all your advice ,I ended up finding a blockage of coal ash, bottom of stove pipe. Manometer looked ok because baro damper was opening allowing draft to power venter. (Past blockage)