- Nov 27, 2012
- 0
Question:
Can you please help me out or point me in the right direction on this? I recently purchased a home with a boiler and hot water heater powered by gas. These units vent into a shared flue that also connects to two brick fireplaces (upstairs & downstairs). At the time of purchase, my home inspector suggested that I think very carefully about using the fireplaces if they vent to the same shared flue as gas appliances. His reasoning was that this arrangement would not be up to code for a new house (mine is 32 years old), and even though it is legal, it might not be wise. I consulted two professionals on this: The gas boiler technician who serviced my units said definitely do not use the fireplace to burn wood. He suggested a gas log for safety, although I should point out his company also sells gas logs. A fire fighter acquaintance said that even though the gas log guy is technically correct, he is probably required to be over-cautious on this and is also likely to steer customers in the direction of gas log sales anyway. The fire fighter said the likelihood of danger was extremely minimal, and pointed out the heavy usage marks from the previous owners, who apparently burned wood in the fireplaces without incident for many years under this arrangement. My goal, by the way, is not to heat the entire house with the fireplaces, but rather to use them occasionally for aesthetics. I have yet to light a fire in either. What's your recommendation?
Answer:
The whole arrangement sounds questionable. Here are some guidelines.
1. Gas boilers and hot water heaters, in recent years, have usually been vented into liners which extend all the way up the existing chimney to the top. Venting them into a large flue that is masonry is asking for trouble, specifically erosion of the flue and the possibility of leakage of flue gases into the home.
2. In general, fuels should not be mixed. Wood and gas should not vent up the same flue.
3. Even the wood fireplace chimneys should have clay liners in them...check to see if yours does. Most fireplaces built in the last 100 years should be lined.
One possible solution, if the flue area is large enough, might be to line the chimney using stainless steel to feed the basement boilers and hot water heater - they can share one flue. It may be that the area around this flue would still be large enough to vent the fireplace gases.
A better solution might be to line with aluminum (cost less) to the basement units, and drop a second stainless liner to feed a small stove or fireplace insert installed into the fireplace(s).
A knowledgeable stove shop or chimney sweep will probably have better advice than the gas tech or fireman. I'd suggest you find a local professional and consultant. The inspector was right - you should be wary. --
Can you please help me out or point me in the right direction on this? I recently purchased a home with a boiler and hot water heater powered by gas. These units vent into a shared flue that also connects to two brick fireplaces (upstairs & downstairs). At the time of purchase, my home inspector suggested that I think very carefully about using the fireplaces if they vent to the same shared flue as gas appliances. His reasoning was that this arrangement would not be up to code for a new house (mine is 32 years old), and even though it is legal, it might not be wise. I consulted two professionals on this: The gas boiler technician who serviced my units said definitely do not use the fireplace to burn wood. He suggested a gas log for safety, although I should point out his company also sells gas logs. A fire fighter acquaintance said that even though the gas log guy is technically correct, he is probably required to be over-cautious on this and is also likely to steer customers in the direction of gas log sales anyway. The fire fighter said the likelihood of danger was extremely minimal, and pointed out the heavy usage marks from the previous owners, who apparently burned wood in the fireplaces without incident for many years under this arrangement. My goal, by the way, is not to heat the entire house with the fireplaces, but rather to use them occasionally for aesthetics. I have yet to light a fire in either. What's your recommendation?
Answer:
The whole arrangement sounds questionable. Here are some guidelines.
1. Gas boilers and hot water heaters, in recent years, have usually been vented into liners which extend all the way up the existing chimney to the top. Venting them into a large flue that is masonry is asking for trouble, specifically erosion of the flue and the possibility of leakage of flue gases into the home.
2. In general, fuels should not be mixed. Wood and gas should not vent up the same flue.
3. Even the wood fireplace chimneys should have clay liners in them...check to see if yours does. Most fireplaces built in the last 100 years should be lined.
One possible solution, if the flue area is large enough, might be to line the chimney using stainless steel to feed the basement boilers and hot water heater - they can share one flue. It may be that the area around this flue would still be large enough to vent the fireplace gases.
A better solution might be to line with aluminum (cost less) to the basement units, and drop a second stainless liner to feed a small stove or fireplace insert installed into the fireplace(s).
A knowledgeable stove shop or chimney sweep will probably have better advice than the gas tech or fireman. I'd suggest you find a local professional and consultant. The inspector was right - you should be wary. --
