Single Chimney usage for 2 burners

[Jackofthetrade]

Adding a Coal/Wood add on boiler to an exisiting Oil burner boiler customer with a metal chimney. The manufacturer of the add on stipulates masonry chimney as per NFPA. The manufacturer recommends the use of a separate chimney but also states a single chimney can be used with proper drafting.

Anyone run into any issues with single chimney usage ?

[mcaylor]

I don't believe there is any instance where you would connect a wood burning device to the same chimney used by any oil or gas furnace or water heater. You might be able to connect two woodburning units in the same flue. In general, the wood burner's flue temperature will be much higher, unless it is a wood gasification unit where the flue temps are greatly decreased. Even then, you wouldn't want to use the same flue. I would bet that any professional will tell you that you need two flues in your chimney. A metal chimney for the woodburner should be triple wall stainless steel.

[big johnson]

Find out what NFPA says and local codes and follow it to the letter. Too much liability involved and you may want to sleep better at night knowing you've done the right thing for your customer.