Two applianecs on one flue ?'s

[cuttingedge]

We are moving to our house in Maine after the new year. The current set-up is, in the basement an oil heater and our Cawley 600 wood stove share the same flue. Upstairs we have an older insert with a blower. Although the set-up in the basement is "Grandfathered", I know that this is not an ideal. Since we are moving to the house during the winter I have some questions regarding safe burning practices. Being that the house is vacant, we turned the heat to 55 degrees to save on heating oil. When we arrive I will obviously turn the heat up to make the house comfortable. Since we have a stove in the basement and an insert upstairs, I would like to primarily heat with wood.

My questions are:

1. Can I use the wood stove while the heat is turned on?
2. Should I worry about using the stove and oil heater simultaneously being that they share a common flue?
3. What would be the ideal stove top temps for an old stove like this?

Thanks for any suggestions,
Jason

 

[MDFisherman]

Does that furnace have any type of backdraft protection? I would be very worried about the woodstove exhaust fowling the heat exchanger in that furnace.

A much safer route would be to disconnect one of the appliances while using the other one.

Be sure to have your chimney checked/swept.

 

[Jags]

Is the insert upstairs on its own flue?

 

[cuttingedge]

Is the insert upstairs on its own flue?

Does that furnace have any type of backdraft protection? I would be very worried about the woodstove exhaust fowling the heat exchanger in that furnace.

A much safer route would be to disconnect one of the appliances while using the other one.

Be sure to have your chimney checked/swept.

I do not know about backdraft protection with the oil heater. The heating system was completely rebuilt this year, and they added a few modifications. Unfortunately I was not at the house to ask what they did but I did notice that the added a "flapper" to the pipe that enters the chimney as well as changing most of the pipe. What do you mean as far as disconnecting one of the appliances?

 

[cuttingedge]

Is the insert upstairs on its own flue?

Yes the insert is on its own separate chimney. The problem is that it is at the other end of the house (away from the bedrooms) so I am not sure that it alone will be sufficient at heating the house. We are going to have a stove (Jotul F55) installed next year in place of the insert.

 

[webbie]

Stove temps would be similar to most others with a single wall top.....from about 400 to 700 in normal operation, hotter is fine - especially on the cook plates.

The common flue question is tougher to answer. Most modern codes forbid it unless the specific combo are tested (like a multi-fuel), BUT the reasons they do so are mostly common sense. That is, most flues are correctly sized to an appliance, so a small (7x7 ID) flue for the oil burner may not have enough capacity (draft) for the two appliances operating at full

Unlike most other states, Maine had actually addressed these situations in state code years ago and did allow multiple venting for oil and wood - IF the flue capacity equaled the combination of both appliances, etc. - your installation may have happened under this code.

Whether that code has been continued is something I don't know (and doubt....).....

So, the answer is a bit fuzzy. You can gauge the capacity of the flue based on some commonly available tables of height and size. However, code and insurance and safety wise, you'd have to check with the ME fire marshalls office or other authorities and see what the current situation is.

 

[MDFisherman]

I do not know about backdraft protection with the oil heater. The heating system was completely rebuilt this year, and they added a few modifications. Unfortunately I was not at the house to ask what they did but I did notice that the added a "flapper" to the pipe that enters the chimney as well as changing most of the pipe. What do you mean as far as disconnecting one of the appliances?

I mean physically removing the flue pipe and closing the chimney opening.

There are many types of backdraft dampers, spring loaded, manual and electronic. You can do a google search.

I am not sure if this is approved by your local codes but it would be piece of mind for myself and the appliances to install some backdraft dampers. Personally I would add a manual butterfly damper one each of the flue's and only use one appliance at a time opening the one you will be using and closing the one not in use. The dampers should seal tight to prevent leaking and should be placed as close to the chimney as possible.

You need to be worried about solid particulates getting into your wood furnace for safety and efficiency reasons. You also need to worry about the oil furnace venting properly or you could get CO escaping through the woodstove.

THIS IS NOT A PERMANENT SOLUTION! If you plan on burning wood you need to install a dedicated flue for each appliance.

Please be sure you have some CO detectors installed if not already.

 

[Jean-Claude]

Wood stove under the stairs??? Doesn't seem safe for some reason.

 

[begreen]

Wood stove under the stairs??? Doesn't seem safe for some reason.

Nor does having a woodstove a couple feet away from a boiler seem acceptable. Does someone know the mechanical code here?

 

[Jean-Claude]

I've seen lots of stoves located close to oil boilers in my region. The boiler already has a pressure relief valve on it so even if the wood stove radiated heat it's protected. Oil doesn't explode like natural gas or propane so I don't see a huge issue there either. But under the stairs??? Can't be good for the homeowner or firefighter needing to access the basement in case of a wood stove problem, and egress from the basement could be hindered as well.

 

[cuttingedge]

I've seen lots of stoves located close to oil boilers in my region. The boiler already has a pressure relief valve on it so even if the wood stove radiated heat it's protected. Oil doesn't explode like natural gas or propane so I don't see a huge issue there either. But under the stairs??? Can't be good for the homeowner or firefighter needing to access the basement in case of a wood stove problem, and egress from the basement could be hindered as well.

Ok I understand everyone's concern. The house has been set-up this way for a long time and obviously the previous homeowner (my great uncle/ aunt) did not have any problems with the way it's set-up. I understand that it is not ideal but was hoping that I could use it as it is for this season. The stairs have sheet metal to protect them and heating oil is not nearly as flammable as say propane or natural gas. BTW I have been a firefighter for 12 years. So should any problems arise, I know what to do.

 

[cuttingedge]

Ok I understand everyone's concern. The house has been set-up this way for a long time and obviously the previous homeowner (my great uncle/ aunt) did not have any problems with the way it's set-up. I understand that it is not ideal but was hoping that I could use it as it is for this season. The stairs have sheet metal to protect them and heating oil is not nearly as flammable as say propane or natural gas. BTW I have been a firefighter for 12 years. So should any problems arise, I know what to do.

I hope that I did not come across as arrogant with that post. If I did I am sorry.

 

[cuttingedge]

Some good news,
I have just been in contact with a family friend whom spent a lot of time in the house during the previous winters.
He said that both the wood stove and the oil furnace were both used together all winter. He also said that the flue has the capacity for both appliances and that he remembers that the only time that the wood stove was not being used was when it was full and needed to be cleaned out.
This at least puts my mind at ease for this year.

Thank you for all of the replies