Stoker Hopper Fire
Speaking with a guy yesterday he said he knew someone who had their Stoker fire in the unit "backup" and catch the hopper of coal on fire. I told him I did not think this can happen. Anybody know if this is possible and if so under what conditions? Thanks!
- Adamiscold
- Member
- Posts: 1116
- Joined: Fri. Feb. 29, 2008 7:09 am
- Location: Winchendon,Ma
Isn't one of the reason for a hopper fire is leaving the ash door open for an extended period of time?
- CoalHeat
- Member
- Posts: 8862
- Joined: Sat. Feb. 10, 2007 9:48 pm
- Location: Stillwater, New Jersey
- Stoker Coal Boiler: 1959 EFM 350
- Hand Fed Coal Stove: Harman Magnafire Mark I
- Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
- Coal Size/Type: Rice and Chestnut
- Other Heating: Fisher Fireplace Insert
A hopper fire can start due to improper draft, the fan forced fire on the grate has to vent the products of combustion somewhere. If there's no or poor draft the stove has to vent somewhere, if a positive pressure develops inside the stove it has to go somewhere. If the pressure starts to feed up through the coal and into the hopper a fire can result. A direct or power vent system is more likely to cause this if the motor on the vent fails. I have no hands-on experience with these systems but I think they have a safeguard switch on them if this occurs.
The other causes of a hopper fire is using the wrong size coal that allows combustion to vent back into the hopper and not having the areas around the grate properly sealed.
Many hopper-fed stoves have a tight fitting lid on the hopper to keep the hopper tightly sealed to help prevent a hopper fire. I have no lid on my stoker and have no problems with the fire burning back into the hopper.
Also a stoker runs on a very low draft, a good chimney will provide more then enough drafting potential, hopper fires become a non-issue.
A properly installed stoker stove with a good constant draft and operated properly won't have hopper fires.
The other causes of a hopper fire is using the wrong size coal that allows combustion to vent back into the hopper and not having the areas around the grate properly sealed.
Many hopper-fed stoves have a tight fitting lid on the hopper to keep the hopper tightly sealed to help prevent a hopper fire. I have no lid on my stoker and have no problems with the fire burning back into the hopper.
Also a stoker runs on a very low draft, a good chimney will provide more then enough drafting potential, hopper fires become a non-issue.
A properly installed stoker stove with a good constant draft and operated properly won't have hopper fires.
- Richard S.
- Mayor
- Posts: 15234
- Joined: Fri. Oct. 01, 2004 8:35 pm
- Location: NEPA
- Stoker Coal Boiler: Van Wert VA1200
- Coal Size/Type: Buckwheat/Anthracite
There's along thread here with a lot of info. Hopper Fire - Alaska Channing 3 With Direct Vent
- CoalHeat
- Member
- Posts: 8862
- Joined: Sat. Feb. 10, 2007 9:48 pm
- Location: Stillwater, New Jersey
- Stoker Coal Boiler: 1959 EFM 350
- Hand Fed Coal Stove: Harman Magnafire Mark I
- Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
- Coal Size/Type: Rice and Chestnut
- Other Heating: Fisher Fireplace Insert
Richard, I was looking for that thread but I couldn't find it.
The first year I bought my Alaska 3 I let the coal get too low in the hopper while it was set on a low setting. The hopper is like a funnel in that coal gets stuck on the sides and then an opening forms where the coal usually is pushed on to the grate. The DV unit is always pulling full force. They design the unit to handle the largest fire that is possible but when the stove is on low there are minimal fumes and much of the heat is pulled out of the stove. Anyway, the coal on teh sides of the hopper caught on fire and eventually burned itself out. One time it happened I was away and came back to ash in my hopper. It was a mess to clean up and scary too. The next time I was home and had to push the hot ashes out of the hopper into the ash pan. The 2nd time it melted my feed control box. After that I installed a rheostat and baro. I now feel safe.
- Richard S.
- Mayor
- Posts: 15234
- Joined: Fri. Oct. 01, 2004 8:35 pm
- Location: NEPA
- Stoker Coal Boiler: Van Wert VA1200
- Coal Size/Type: Buckwheat/Anthracite
Google gives better results for specific phrases when you use quotes:Wood'nCoal wrote:Richard, I was looking for that thread but I couldn't find it.
**Broken Link(s) Removed**
- CoalHeat
- Member
- Posts: 8862
- Joined: Sat. Feb. 10, 2007 9:48 pm
- Location: Stillwater, New Jersey
- Stoker Coal Boiler: 1959 EFM 350
- Hand Fed Coal Stove: Harman Magnafire Mark I
- Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
- Coal Size/Type: Rice and Chestnut
- Other Heating: Fisher Fireplace Insert
Thanks Richard and Trader on the search tips.
On my Alaska I let the hopper run too low once. Apparently when the coal ran out over the carpet the fire just went out, the hopper has square corners on the bottom, the coal there was untouched. The only reason I can see for this is that my stove is piped into a chimney, not a power or direct vent.
On my Alaska I let the hopper run too low once. Apparently when the coal ran out over the carpet the fire just went out, the hopper has square corners on the bottom, the coal there was untouched. The only reason I can see for this is that my stove is piped into a chimney, not a power or direct vent.
Hopper fires are the reason you should use a properly set baro damper on stoker stoves. Too much draft will cause air to be drawn from the hopper and the coal fire will follow the draft up into the hopper. The lower the coal gets in the hopper the more air the draft can suck through the coal and soon you have enough air moving through the coal in the hopper to support combustion. With a properly set draft and using the right sized coal you should be able to let the hopper go empty without any issues.jrn8265 wrote:Speaking with a guy yesterday he said he knew someone who had their Stoker fire in the unit "backup" and catch the hopper of coal on fire. I told him I did not think this can happen. Anybody know if this is possible and if so under what conditions? Thanks!
-
- Member
- Posts: 381
- Joined: Mon. Jan. 23, 2006 7:30 pm
- Location: Berwick, pa
- Contact:
Well said gambler. You hit it on the head.
Jerry
Jerry
- k9 Bara
- Member
- Posts: 499
- Joined: Mon. Mar. 31, 2008 11:27 am
- Location: Red Creek, Fair Haven area NY
- Stoker Coal Boiler: 1996 EFM 520 DF
- Coal Size/Type: Buck / Reading
OK guys, you got me thinking and nervous. Does this happen to direct vent stoves? If so, what do I need to do to prevent it?
Thanks,
George
Thanks,
George
I am not familiar with direct venting but I think that you need to measure the over fire draft and a way to adjust the direct vent to regulate the draft.
I am sure some of the other members with direct vent experience will chime in.
I am sure some of the other members with direct vent experience will chime in.