High CO levels this morning.

Hey everyone I have some questions concerning carbon monoxide. I’ve had a detector down by my furnace since I’ve been burning and it never went off but does not give an actually number that you can read, just goes off when it’s too high. I bought two more and set them up last night and this morning all 3 in different locations were going off. Highest reading I got was 50 in the basement. I have no idea why all of a sudden.

First thing I though was maybe my fire is not hot enough. It’s been in the 50s during the day and I have the air cut way back on it to slow the burn. At night the temps have been in the 30s still.

When they went off I opened some doors and windows and opened the ash door. Shook the ash and let the fire get ripping. After 20mins I reset them all and shut all the doors and windows. They’re all reading zero now since then. And the highest saved reading I’ve gotten since resetting has been zero on all three levels of the house.

So my question would be is this a draft problem ? Or is it a fire not hot enough problem ? Even tho I have the air cut back the fire is still plenty warm enough to keep my house 68-70 through the 30-40 degree night. The fact that the fire takes off within 20mins with the ash door wide open, even after a 12 hour burn still loaded with ash has me confused.

In my mind I should be able to cut the air to the fire back as much as I need to slow the burn, and as long as it’s still drafting any carbon monoxide it produces should just go right up the chimney ? I’m new to this coal burning thing so maybe I’m not understanding drafting correctly ? Or could one of my pipes be leaking back into the house ? As of now I’m just letting the fire finish burning out until I can come up with a reason for why it got that high. Any help or opinions would be much appreciated!

I would start by installing a manometer to monitor the draft.

Yes, it could depend on your chimney and draft settings. LIke lee said, get a draft gauge/manometer, mine will go off if I leave the ash door open too long while changing the pan, etc....some may leak out if the doors are opened/closed, depending on the draft you have. sometimes when it's warmer, you have to run a little hotter to keep a good draft.

Lightning wrote: ↑

Thu. Dec. 26, 2019 11:52 am

I would start by installing a manometer to monitor the draft.

Yeah I just ordered the one you recommended to me . I Just can’t understand how it can burn so well and not be drafting properly.

Right.. that is puzzling. It might be a brief draft reversal due to wind direction or some other factor. Refresh me about your setup. In the basement, I assume. Do you have a cold air return back to the furnace from the living area?

Yeah it has a cold air return upstairs. I’m still learning this whole forced air thing. I’ve always had hot water. But could the fact that I’m sharing a flu with the oil furnace be causing some other issue somehow ?

Jared220 wrote: ↑

Thu. Dec. 26, 2019 12:21 pm

Yeah it has a cold air return upstairs.

Is it plumbed directly to the furnace?

Yeah the sharing flue could surely impact your draft..

Lightning wrote: ↑

Thu. Dec. 26, 2019 12:45 pm

Is it plumbed directly to the furnace?

Yeah the sharing flue could surely impact your draft..

The way it looks to me is the cold air return goes from my bed room back to the just the oil furnace. I don’t see anyway it’s tied into the coal furnace

Okay.. do you leave the basement door open so that air can return to the coal furnace?

Lightning wrote: ↑

Thu. Dec. 26, 2019 1:28 pm

Okay.. do you leave the basement door open so that air can return to the coal furnace?

No actually I do not. I always keep it closed simply because my thermostat is close to the basement door. Sounds like I should not be doing that ?

Okay... I think we're making progress here.. my hypothesis is that the convection blower on the coal furnace is creating a low pressure area in the basement, effectively sucking exhaust back down the chimney. This would be even more evident during mild weather and cooler burns.

That, coupled with sharing a flue is destroying the chimney draft. Do you depend on the oil burner at all? If not, I would suggest a lock out, tag out, cut power to it and stuff the oil burner's exhaust pipe with fiberglass insulation.

You can do a lot of air current and leak checking with a smoke/incense stick place where direction or leak might be suspect...
Also, with weaken fire it can be easier for other household exhaust equipment to over come any weak chimney draft, like clothes dryer and kitchen and bath exhaust fans ...All this especially with a 'shared chimney'...can you cover oil furnace barometric damper with aluminum foil?
Does home have a fireplace?

Lightning wrote: ↑

Thu. Dec. 26, 2019 1:49 pm

Okay... I think we're making progress here.. my hypothesis is that the convection blower on the coal furnace is creating a low pressure area in the basement, effectively sucking exhaust back down the chimney. This would be even more evident during mild weather and cooler burns.

That, coupled with sharing a flue is destroying the chimney draft. Do you depend on the oil burner at all? If not, I would suggest a lock out, tag out, cut power to it and stuff the oil burner's exhaust pipe with fiberglass insulation.

I don’t use it for anything. I actually have it turned off in the breaker box. I can Disconnect it then block off the flu behind the Boro.

So do you think by keeping the basement door closed it is causing the basement to become more of a low pressure area ?

Also as far as the cold air return goes. Should there be on to the actual coal furnace ? Or the fact that there is one to the oil furnace is good enough even tho the oil furnace doesn’t run at all ? Not sure I fully understand how the cold air returns work so sorry it If I sound ridicules