Gasser"& oil Boiler same chimney?

[ozzie88]

I read on different web. sites that if the oil boiler goes into chimney above wood boiler it be ok?
[ htpp:WWW.InspectAPedia.com/chimneys/shared_chimney_flues_OK.htm ] ] And also wood boiler has to have its own air supply different from oil boiler? And the air has to be able to shut off Completely when running other boiler to not effect the burning or draft of the running boiler.
The chimney would have to be cement block big enough for both if ever run together,[which hardly would happen] I can see how bad it could effect the draft of the boilers but if done right like i read should work ok from what i can tell?
Or would it just be better to power vent oil boiler outside and leave gasser alone?

 

[JP11]

ozzie

In Maine when fuel got expensive in 08 they reversed there previous law change saying no two appliances in one flue. The kicker is that they said that it's only for homes older than X years that already had it installed that way. To me... and what my plumber said was... That's dumb! It's either safe to have or it's not. But typical politicians.. when the heat was on with high oil prices, they caved.

Power vent would be the way around it. Common sense of having enough draft doesn't play into it.

JP

 

[maple1]

Mine are both into one 7 inch stainless flue. Oil over wood. Sometimes the oil kicks on when there is a wood fire going - no biggie, although depending on conditions sometimes it will puff a very small puff of smoke out the wood draft door. Check your local codes, they vary. Some might rule it out all together, some might want a cut out on the oil so it can't come on when the wood is burning.

 

[stee6043]

That's a big no-no here in Michigan. I have no clue about other states. In my humble opinion it seems like a bad way to save money. I'd power vent your oil boiler and sleep soundly at night. Just my two cents.

 

[pybyr]

I had a wood/ hot air furnace and an oil hot air furnace on a shared flue when I first bought my house. It worked fine but from everything I understand, is a no-no under anything considered current codes or good practices. I had to rebuild the masonry chimney anyway, so built the new one with 3 separate flues (oil, wood central unit, and the wood cookstove in the kitchen).

I personally would NEVER put a wood gasification boiler and an oil appliance (or anything other than the wood gasification boiler unit unit) on the same flue. Some wood-G units with some batches of wood can experience conditions where you get momentary but substantial pressure in the flue from situations where wood gas production briefly occurs faster than combustion- and then combustion catches up all at once. Sometimes it's a series of pulses, sometimes it's a big WHOOMP. Those events vary in frequency, pattern and intensity but do definitely seem to carry-push some significant amounts of very fine fly ash with them. Either way (pulsating woofing or big whoomp) it is nothing that I would want to have at risk of being directed into a separate combustion appliance or any flue, flue pipe, barometric damper, etc., that have not been specifically set up/ expected/ tested to fully "meet" these potential conditions.