Rotten Egg Smell WL-110

I had similar problem with my 110 last week as we had the rotten egg smell and the carbon monoxide detector went off . I also shut down the boiler and opened doors and windows in freezing temperatures . I turned on the oil boiler and did a complete cleaning of the coal boiler the following day . I brushed out the tubes this time as I had vacuumed the top not to long ago . We have had very cold temps and the boiler has been running almost non stop . I usually have to vacuum the top section about once a month due to lots of fly ash . I have a good manometer reading and a clean flu pipe . I use to brush out the tubes every other time I vacuumed and this year I didn't do that , so that was the culprit in my case I guess . I have always used the same coal as it is the only one available in my area . The boiler is running fine now . It doesn't take long to vacuum and brush out the tubes as I can do it without shutting down the boiler . I will have to do a better job now as I did in past years with no problems . It was a wake up call for sure .

Yep, best to not wait for the manometer to tell one that a cleaning is about due.