Woke up this morning to CO alarm going off. The monitor is in the back living room where our insert is. I had it throttled all the way back for the overnight burn and there was a moderate bed of coals left this morning. Fire company and gas company say it’s tbe boiler in the basement as it was back drafting a little when they did some test however the basement had minimal co in it. My concern is could my insert have back drafted that bad to spill into our house and reach the whole way upstairs? I worked til 4 am yesterday morning and when I came he no alarm. However when I got up at 10 it was going off. The outside temp also went from 36 degrees to 60 in a just a few hours. I live in south central PA. My boiler has been red tagged and is going to be completely replaced. My concern is it was the insert. The gasket has a small fray at the bottom right in the middle of the door. It has been that way since we got it new and have not had a problem thus far. Am I wrong to think it was the stove and not the boiler?
CO alarm
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wooduser
Minister of Fire
Interesting question. I used to be a first responder for the gas utility I worked for, so I would have been the guy from the gas company.
The salient fact to keep in mind is that carbon monoxide has almost the same specific gravity as air, so once it get in the air of a house it tends to hang around, sometimes for hours.
Your wood stove is almost certainly making large amounts of carbon monoxide, which is a main component of wood gas produced when wood is burned. So it's essential to be sure that it is venting reliably and not back drafting into your home. Did the fire department or gas company test for CO around the insert and the venting? They should have. The insert and the venting should all be under negative pressure so that room air goes into any leaks on the stove or vent pipe.
Usually a back drafting wood stove or insert would announce that issue by venting smoke into the room, you might look over the insert and venting carefully for any smoke coming into the room when it's operating. Have you noticed any odor of smoke around you insert? I would expect that CO from your insert would be linked with a smoky odor, although CO by itself is odorless.
The boiler might just need cleaning and maintenance to make it work right. The most common issue in boilers vented into unlined masonry chimney is the brick grout on the inside of the flue deterioration, falling to the bottom of the flue and blocking off the gasses from the boiler. Alkl that needs to be done in that case is to dig out the sand and clean and maintain the boiler so that it's not making CO.
It may be simpler, faster and a lot cheaper to have a salty old furnace repairman to come out and analyze what's going on and what can be done about it.
A red tag usually has a written statement of the reason for disconnecting the appliance. What did that say? How old is the boiler? When was the last time the boiler was serviced by a repairman?
I'm sure others here can provide better advice than I on the insert.
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wooduser
Minister of Fire
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Wood smoke smell will not necessarily be found with CO coming from the stove in a reverse draft . I’ve had it happen with no smell - at the end of a burn with just coals left.
When the fire department was at my house, they used their sensitive handheld around the furnace and woodstove to see if they could pinpoint the issue but could not.
One thing about regular household CO alarms is that they don’t go off until you have a certain level register for a certain amount of time - so, for example, CO would need to be at 70 for an hour before the alarm sounds. This can make it more of a challenge to nail down the source. If they found a reverse draft at the boiler, then that seems like reason for concern and if it had been drafting for a while with the boiler off, then clean air coming in the basement through the boiler vent could have been pushing CO air upstairs. Do you have a monitor in the basement as well?
When the fire department was at my house, they used their sensitive handheld around the furnace and woodstove to see if they could pinpoint the issue but could not.
One thing about regular household CO alarms is that they don’t go off until you have a certain level register for a certain amount of time - so, for example, CO would need to be at 70 for an hour before the alarm sounds. This can make it more of a challenge to nail down the source. If they found a reverse draft at the boiler, then that seems like reason for concern and if it had been drafting for a while with the boiler off, then clean air coming in the basement through the boiler vent could have been pushing CO air upstairs. Do you have a monitor in the basement as well?
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There was no Smokey smell throughout the house which was why they were convinced it was the boiler. The boiler is 40 years old and makes sense if it’s starting to fail. It was serviced 2 years ago. Our water heater and boiler vent into our masonry chimney which is unlined. A chimney sweep came and did a video inspection which showed most of the mortar missing, and there were able to see the cinder block foundation of our house . Columbia gas and the fire company were convinced there was a blockage in the chimney since the boiler was back drafting. however the chimney was wide open. They were unable to detect any CO around the stove, but the patio door in that room had already been open.
As I said earlier my biggest concern is that the stove was leaking. Is it possible that simply the weather caused all of this?
We don’t have a monitor in the basement but we have on at the top of the basement steps as we didn’t know if we would her it down there.
The red tag says due to not venting properly
As I said earlier my biggest concern is that the stove was leaking. Is it possible that simply the weather caused all of this?
We don’t have a monitor in the basement but we have on at the top of the basement steps as we didn’t know if we would her it down there.
The red tag says due to not venting properly
Sawset
Minister of Fire
Maybe not expertise, but I've experienced somewhat similar types of situations, where outside conditions have contributed to backdrafting. Usually, the conditions are calm, humid, with a pronounce rise or elevation in temperature. Air inversion may be a possibility. Pilots call it heavy air. A look at fog or smoke outside that appears to flatten into layers would indicate an inversion. If the layer is at or just above the top chimney level, then air escaping through the layer becomes difficult, and backdrafting is a real possibility. Look outside - smoke rising, fanning put, or immediately dropping to the ground all indicate different extents and locations of layering. My stove usually has excellent draft. But sometimes, very rarely, the conditions are just right that lighting the stove is a real chore, with extra time spent initiating and maintaining enough draft to keep smoke out of the house. A couple times I've almost abandoned trying to light the stove because the outside air was so heavy and was seriously blocking any draft. I've never noticed it later when the stove is warm, at least enough to set off any alarms. That doesn't mean it wasn't happening, just that the co alarms haven't indicated it.
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The best answer I have to your question is yes, you can get CO from a stove without a smoke smell. I did, twice, confirmed it at the source with my low level CO monitor the second time (after having my system checked out to confirm there were no apparent issues with the setup). I have since addressed it with some changes that helped me with a strong negative pressure problem in my basement where the stove is. And yes, atmospheric conditions can contribute to a reverse draft. Temperature, wind direction, and many other factors can play a part. But, while weather may contribute, the systems should be set up so that it is not a factor in safe operation.
I would not discount the experience and recommendations of the fire department and gas company that have observed your system first hand. You mentioned that they observed a reverse draft at the boiler and were concerned. It also sounds like you may have flue issues that need to be addressed. If it were my family, I would not operate that equipment again until it has been inspected top to bottom and any potential issues have been addressed. If that CO alarm fails or doesn’t catch it in time, that’s it.
I would not discount the experience and recommendations of the fire department and gas company that have observed your system first hand. You mentioned that they observed a reverse draft at the boiler and were concerned. It also sounds like you may have flue issues that need to be addressed. If it were my family, I would not operate that equipment again until it has been inspected top to bottom and any potential issues have been addressed. If that CO alarm fails or doesn’t catch it in time, that’s it.
I would take this very seriously. Maybe buy a second or even third detector and place one close to the boiler, the other one close to the stove and a third one where you sleep. Also open the window a bit in the room where you sleep and close the door until the problem is identified and corrected.
missedbass
Member
I would make sure you have a roll out switch on the boiler which will shut off the boiler when there is negative pressure and also crack a window in the basement to provide make up air.
wooduser
Minister of Fire
If that's what they did, I consider it sloppy work.
They should have checked to see if the boiler was drafting properly, or whether it was spilling combustion gasses at the barometric damper. And they should have tested the combustion gasses for the level of carbon monoxide found in them. A level of 25 PPM or so is OK (remember these combustion gasses should be going out the chimney) A level of 100 PPM or more is a good indication that the boiler needs to be serviced and inspected.
<<Columbia gas and the fire company were convinced there was a blockage in the chimney since the boiler was back drafting. however the chimney was wide open.
Here you are saying that they actually found the boiler not venting, which typically means they found combustion gasses spilling out of the barometric damper ---- the "flapper" that should be on the vent pipe.
Boilers typically have a long life, and I wouldn't conclude that you need to replace the boiler unless a furnace repairman concludes that the boiler is too deteriorated to repair. I would say that the probability that it can be repaired a a modest cost is good, even if it's causing the problem. A CO/venting problem can usually be corrected by doing needed maintenance work by cleaning and inspecting the burner and venting system ----probably an hour labor charge.
Since it's been two years since you had that done, it's time to do it again anyway.
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wooduser
Minister of Fire
That's a very good idea. As mentioned earlier, if the boiler doesn't vent, the hot combustion gasses come pouring out the barometric damper on the vent pipe ---the "flapper." A temperature sensitive switch can be installed on the damper which will trip if it's hit by hot combustion gasses, and shut off the boiler until it's serviced. These can be retrofitted pretty cheaply and offer good protection against a boiler that isn't venting.
wooduser
Minister of Fire
Well, I'm not a wood stove Xpert. But I would want a venting system that will ALWAYS vent, and NEVER vent combustion gasses/smoke into a room except when the door is open and the stove is being charged with firewood and such.
The idea of having a stove that will fail to vent at night and flood a house of sleeping people with carbon monoxide gives me the willies!
I don't consider it acceptable even when the stove door is open and being fed wood.
Lot going on here so lets try and sort through:
- You first say the CO monitor is close to the insert, but then worry that the insert backdrafted to reach 'the whole way upstairs'?
Not sure how to reconcile that. CO is roughly the same density as 'air' so it doesn't have a great tendency to float or sink. It would generally be produced by combustion, so might be a bit warmer and have a slight tendency to rise, but CO detectors are perfectly happy near the floor (ie plugged into an outlet) in contrast to smoke detectors which are always on the ceiling. But either way, an insert burned down to coals would be mainly emitting CO and CO2, not smoke - so entirely possible to get a CO alarm with no smoke smell. Basically, if you have the option to track concentration, then wherever the concentration is highest, that is the source.
- Outside temp going from 36 to 60 in just a few hours
Presume you mean the outside temps were doing that while the insert was burning down? If that is the case, then it's probably the 'worst case scenario'. If your insert is cooling and the outside air is warming then you're loosing draft at a much faster rate. Generally, the fire is burning down as you go through the night - which also means colder temps outside - so sort of a wash.
- Gasket has a small fray
Likely irrelevant to this issue. A leaky gasket will make it hard to control inlet air and may lead to an overfire/runaway situation. But for CO backdraft, the insert already has an air inlet and that would allow CO out just as well as it allows air in. So fixing the gasket may help burning, but won't do a thing for CO.
- Wrong to think it was the stove, not the boiler?
Well, we've been talking about an insert all this time... are you just using 'stove' as an analogous term or are there really three appliances here? ...stove, insert and boiler?
My fault, the stove and insert are the same thing. The boiler is 40 years old and doesn’t really have any safety trips. The gas guy lit a match at the vent of the boiler and it started back into the basement. They then concluded there must be a block in the chimney. So later that day a sweep came out and concluded the chimney was clear however is missing all of the mortar between the tiles and were able to visualize our cinder block foundation. An HVac man came and said we needed a flue liner, but had to keep our boiler shut off until it was put in. He could not pin point the reason it was back drafting therefore he and his boss said the safest thing to do is replace it, as a new boiler will have all of the safety features in place to prevent this from happening.
We have bought four new detectors now including one in the basement. The boiler was red tagged by the gas company and the hvac company agreed the best bet is to leave it off until it’s replaced. The gas and pilot are now off to the boiler. We have not been using our insert either since the incident and have been sleeping in front of our pellet stove .
All should be replaced on Thursday including a chimney liner with new boiler and water heater. Yes it’s an investment but why take a chance on something so old. We had planned to replace it when we bought the house but were told at the time to run the boiler in to the ground because they last forever. And that was when we also purchased our CO detector Incase this day came
We have bought four new detectors now including one in the basement. The boiler was red tagged by the gas company and the hvac company agreed the best bet is to leave it off until it’s replaced. The gas and pilot are now off to the boiler. We have not been using our insert either since the incident and have been sleeping in front of our pellet stove .
All should be replaced on Thursday including a chimney liner with new boiler and water heater. Yes it’s an investment but why take a chance on something so old. We had planned to replace it when we bought the house but were told at the time to run the boiler in to the ground because they last forever. And that was when we also purchased our CO detector Incase this day came
missedbass
Member
A new boiler will come with all the latest safety switches ( roll out , spill switch, etc.) and be more efficient and give you piece of mind but your draft issue still needs to be addressed. You need to make sure that you have plenty of make up air available.
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