I have a K2 keystoker coal boiler that I've had for a few years. This season when I just began using it, it's been blowing a coal smell from the venter.
The venter has a small motor that runs a fan on the outside of the vent and a larger fan inside the exhaust vent. There are air slots behind the motor and around the first fan. The smell is coming from the outside fan air slots. It's a warm coal smell but not an exhaust smell. The draft is checked repeatedly and kept as close to a .02 wc. The vent has heat tape around every connection. There is a c0 detector near the boiler which registers no ppm at all.
I've called keystoker and they thought it might be the venter was dirty and partially blocked. Right after the call, I turned off the boiler and disconnected the venter. I was unable to remove the set screw holding the larger fan so I used a flexible vacuum hose with a small tip as well as a can of compressed air to clean everything. I also tapped the entire piece which removed a lot of ash and rust. Finally I oiled the mechanisms at the fan shafts as well as the draft slider. The venting out of the house was checked and cleaned as well.
![[Hearth.com] Coal boiler smell](https://www.hearth.com/talk/attachments/img_20191109_150859-webp.250984/ "[Hearth.com] Coal boiler smell")
Once restarted there was no coal smell. I tried to smell coal inches from the venter but there was nothing. After some time passed and the boiler reached higher temps the smell returned.
The only solution I can come up with is to block the air vents around the first fan, but doing so would probably result in fan motor over heating and a quick failure. What can I do to eliminate the smell?
The venter has a small motor that runs a fan on the outside of the vent and a larger fan inside the exhaust vent. There are air slots behind the motor and around the first fan. The smell is coming from the outside fan air slots. It's a warm coal smell but not an exhaust smell. The draft is checked repeatedly and kept as close to a .02 wc. The vent has heat tape around every connection. There is a c0 detector near the boiler which registers no ppm at all.
I've called keystoker and they thought it might be the venter was dirty and partially blocked. Right after the call, I turned off the boiler and disconnected the venter. I was unable to remove the set screw holding the larger fan so I used a flexible vacuum hose with a small tip as well as a can of compressed air to clean everything. I also tapped the entire piece which removed a lot of ash and rust. Finally I oiled the mechanisms at the fan shafts as well as the draft slider. The venting out of the house was checked and cleaned as well.
Once restarted there was no coal smell. I tried to smell coal inches from the venter but there was nothing. After some time passed and the boiler reached higher temps the smell returned.
The only solution I can come up with is to block the air vents around the first fan, but doing so would probably result in fan motor over heating and a quick failure. What can I do to eliminate the smell?
