Sulpher Smell and Low Co Reading in Hopper

I have a Harman magnum stoker that sometime emits sulpher smell and Co from the hopper. It seems more present on milder days 30 to 40 degree days when the stove cycles in pilot mode. The last three days it was fine but today it was back. I have tried to adjust the air on the fire box blower to correct but I may have other problems. my baro damper only moves on windy days but I think my chimney may be incorrect. I have 6in single wall pipe inside and out total height about 20 foot . Could my chimney be too cold on the outside and cause draft problems? It will suck smoke off of candle in damper when fire blower is running. I am going to get ahold of draft meter tomorrow and check. would a double wall pipe help keep draft from cooling off? The stove heats our 40x40 garage and has been running this way for 5 years now and I never checked the Co before (just got meter for something else and thought I should check, never got sick or anything but have a total Co reading of6or7 in garage sometimes) Any thoughts would be appreciated Thanks

You should check the draft with a manometer. Do you open the door to the fire box? That changes the draft and a sulpher smell at the hopper is possible. I've noticed, that I'll get a little smell at the hopper right after opening the door. Opening the door is an old habit from my wood burning days I think. I keep threatening to make a window in my boiler door so I can see the fire without opening the door. I guess I could make a cut out and secure a piece of ceramic glass over it.

Normally when I come home from work I hit the shop to check coal .Usually when I open the shop door to go in its fine but sometimes I smell sulfur mainly when the thermostat put it in pilot mode (on for5 min off for 12 ) this is not a new problem but I want to make it right. Im thinking that my exterior single wall pipes are to blame possibly cooling off and not drafting right in pilot mode because when the stove run continualy I do not get the smell or Co reading ( I have a pro Bacharach snifit meter thats pretty reliable ) Should I go to a dual wall like the simpson pipe ore any others and if so will it help? I have a window in the door so I don't need to open to see how its burning ( runs 500 deg or a little less on the side of heater so it burns good) I don't have to open the hopper to smell the gas but its definitly coming out of there because I checked it with meter!!! Any thoughts? Thanks

Yes it is quite possible that with the colder temps and your stove at idle the chimney is cooling off and not drafting. The double wall insulated chimney pipe will help this situation if in fact that is what is happening.

Is your combustion fan running only when the stoker feed is running? or do you have is set to run full time.. A full time combustion fan will probably keep the heat moving up the chimney, and eliminate the smell..
Without the full time fan, the chimney draft has to pull the air through the fire,, and if the draft is low, it wiil stink in the Hopper.

Greg

Does the building so tight that the coal unit is starving for air? Maybe try leaving a window open a crack on the windward side & see if it helps?

The stove ran fine yesterday no smell or co and still ran in pilot or idle mode. Building has plenty of air leaks at bottom of garage doors so I think intake air is not the problem. Talked with my stove rep at Martin stove in Butler PA and he suggested double wall pipe so I will give this a try but I still dnt know why this will come and go. I hope this will work as the pipe is sold on the GOLD standard!!! (LOL) Thanks