Sulfur Smell in House

Hello everyone,

I have recently started experiencing the rotten egg/sulfur smell in the house whenever my stoker is running. At idle, no smell. Basic details:

-Wagner stoker with a 55 gallon drum hopper
-Purchased Dwyer #25 manometer and at idle get a reading of .07 at the fire box, flue, and ash pit. At full burn, .10. Both seem high to me.
-No baro damper, 7" flue direct from stoker to chimney
-Flue pipe sealed at seams and inlet to chimney
-I've adjusted air input from combustion fan but little change detected
-Seems to be coming from the hopper, smoke visible from hopper at one point and limiting air from combustion fan seems to have stopped that but not the smell. I thought the worm tube was positively pressurized by the combustion fan but I could be wrong. There's a bypass tube from the fan to the worm tube in the fire box and it's clear.
-CO detector reads nothing
-Flames seem to be erratic as compared to last year when they were calm and even
-Stoker runs 24/7/365 as it heats water as well
-All flue pipes, chimney, fire box cleaned of ash.

Any ideas/tips would be appreciated. I'm trying to find my way with this stoker as I have no literature on it and cannot find any. I think I've covered all the basic tests to pinpoint smell but I'm getting nowhere.

Thank you!

When last did you have stove pipe off and clean fly-ash from the horizontal sections and the from the chimney clean out?

The reading of .10 seems suspicious to me, as, if accurate, it would seem impossible for fumes to back up into the hopper. Are you sure the Dwyer is level?

Or is it maybe connected backwards?

McGiever wrote:When last did you have stove pipe off and clean fly-ash from the horizontal sections and the from the chimney clean out?

Just last week when this problem began. There wasn't much in it.

Edit: no chimney cleanout. Chimney is only accessible from the basement where the flue pipe connects.

franco b wrote:The reading of .10 seems suspicious to me, as, if accurate, it would seem impossible for fumes to back up into the hopper. Are you sure the Dwyer is level?

100% certain

McGiever wrote:Or is it maybe connected backwards?

I have the hose connected to the low fitting on the manometer. Is this correct? If connected to the high, I get no reading as the liquid disappears completely into the negative side.

Low port on the mano goes to the stove, leave the high port open to the room. As mentioned, this arrangement will allow you to read negative pressure on the positive side of the scale, where there is more scale to work with.

McGiever wrote:Low port on the mano goes to the stove, leave the high port open to the room. As mentioned, this arrangement will allow you to read negative pressure on the positive side of the scale, where there is more scale to work with.

Thank you, now I understand better. So draft would be sufficient, correct? -.10 seems like I'm wasting a lot of heat up the chimney.

MarkG wrote:

McGiever wrote:Low port on the mano goes to the stove, leave the high port open to the room. As mentioned, this arrangement will allow you to read negative pressure on the positive side of the scale, where there is more scale to work with.

Thank you, now I understand better. So draft would be sufficient, correct? -.10 seems like I'm wasting a lot of heat up the chimney.

Yes, wasting heat. Time for a barometric damper.

Not sure, but hope that will fix the sulfur smell...might have been with the high draft you have that extra air was being pulled in through auger pipe and causing a slight burn back condition that could of allow that smell to release at some point.

That tube from the fan to the worm tube seems like a possibility, because lowering the fan air helps. I think that needs better understanding.

When I first installed the hand fed and was new to coal burning I had the same issue. I had not learned about controlling draft to the fire, I had the stove piped to the chimney without a baro damper. I kept having issues with a combustion smell in the house after the stove was burning for a while, the CO alarm did not sound (it was an earlier model, no display). I finally realized that the coal fire was hotter then a wood fire, it seemed the heat was expanding the slip joints in the adjustable elbows I used in the smoke pipe. I tried sealing everything up with stove cement, didn't help much.

Then I found this forum and read a lot. I bought a manometer and installed a baro damper...the rest is history.

Do you have any of those adjustable elbows in the smoke pipe run? I don't use them anymore.

We all have to go through the learning curve...especially if we replaced a wood stove like I did:

Me as a newbie : Cold Chimney?

Rob R. wrote:Hello Mark, on an underfed stoker like your Wagner there a few things that can allow gasses to come back through the bin pipe. Basically the gasses will take the path of least resistance. Weak draft and/or excessive combustion air can do it, but it sounds like you have ruled that out. That tube that runs from the fan housing to the auger pipe is very important, it should blow air when the fan is on. Make sure it isn't blocked on the coal side of the auger pipe.

Check for a restriction at the end of the auger that prevents the auger pipe from being full of coal. This would be similar to running the bin empty. It would also be a good idea to check the auger for wear. If it is totally shot, it could cause erratic behavior of the fire.

Lastly, do a full cleanout of the pot. Check the air chamber under the grates/rings, and make sure the air holes or slots in the grates/rings are clear. You want an easy path for the combustion air.

Thanks for this, Rob. I will check all of this on the weekend since it's going to be warmer and rainy. Would be the perfect time to shut it down and give everything a good inspection.

What would signify wear on the auger? I'm fortunate enough to have been left a new one by the person we bought the house from in case I need it.

Wood'nCoal wrote:When I first installed the hand fed and was new to coal burning I had the same issue. I had not learned about controlling draft to the fire, I had the stove piped to the chimney without a baro damper. I kept having issues with a combustion smell in the house after the stove was burning for a while, the CO alarm did not sound (it was an earlier model, no display). I finally realized that the coal fire was hotter then a wood fire, it seemed the heat was expanding the slip joints in the adjustable elbows I used in the smoke pipe. I tried sealing everything up with stove cement, didn't help much.

Then I found this forum and read a lot. I bought a manometer and installed a baro damper...the rest is history.

Do you have any of those adjustable elbows in the smoke pipe run? I don't use them anymore.

We all have to go through the learning curve...especially if we replaced a wood stove like I did:

Me as a newbie : Cold Chimney?

Thanks! I do have the adjustable elbows and intend on redoing the flue pipe when I install the damper this weekend so I'll invest in solid 90s. For as cheap as they are, even if it's not the source, it's one less thing to worry about.