Sulfur Smell from Keystoker Bay Window Direct Vent

I have a Keystoker Bay Window Direct Vent and it's been burning great and with no problems the last month or so. The last two days when I came home from work, I noticed a sulfur smell in the house. I have brand new CO detectors with digital readouts and they both register at 0. Yesterday the hopper was about 1/3 full so I thought it might be a little gas sneaking up through the coal but today it was 2/3 full. It's been pretty cold so the stove has been running hard the last couple of days. Could it be the coal in the hopper is getting a little hot and giving off the smell?

Is the coal in the hopper wet?

Have you checked to see if the stove pipe is partially clogged with fly ash?

Have you check and adjust the draft on the Direct, they can be adjust slightly. Maybe it's a bit low or has fly ash not creating enough draft in the stove.

Could be the Coal, i know mine smells a bit of sulpher, but my CO's also read Zero....

You won't smell Co in has none. Sulfur gas is another type of gas that is in coal when you burn it. You will smell Sulfer in the house if you have a poor draft or no draft or the stove is not sealed up correctly. Check your draft & seals on the
stove & DV. Pipe.You will sometimes smell sulfur on the outside aswell on a damp or wet day when the air is heavy. Some coal will have more Sulfer then other's

I got the same smell at beginning of this cold snap along with sweat inside the hopper. Tweaked the rheostat on the powervent a bit and all is well.

If you have been burning a Direct vent for over a month you probably need to clean the flue pipe . With a direct vent the say to clean the pipe at least once per month in the alaska manual. That is one of the major disadvantages of the direct vents and the power vents is the added maintanence. I f yoy are getting sulfur smell or condensatiion on the hopper lid you are haveing draft issues.

I would wrap every joint in the pipe with hi temp tape. I had the same problem, did this, and it went away.

No smell at all today. My coal is dry and there is no condensate in the hopper. All of the pipe joints were sealed with high temp silicone when it was installed this summer. I'll shut her down tomorrow and clean her out. Thanks for all of the tips. This forum is tremendous!
By the way, I got my gas bill from 10/4-11/3 and it was only $61. I did run the heat once for a few hours one day. I compared it to last year and it I used half the amount of gas this year that I used last year. I supported the local economy buying a stove made right here in NEPA from a dealer right hear in NEPA. It burns coal mined right here in NEPA that is delivered to my home by a great guy who lives right here in NEPA. I get some exercise fetching coal from the cellar and taking out the ashes and my house is toasty warm. All this and I'm saving a pile of money. Its a win-win-win all the way around.