Drolet Escape 1800 carbon monoxide issues

[Mmeade]

Help!

Installed my Drolet 1800 escape wood burning insert 2 years ago, haven’t used it much due to draft issues with startup - have that fixed!
However, I can easily start the stove with a top down fire, burns hot and problem free for as long as I keep the damper open and stocked up. I get secondary burn and no black smoke coming from the chimney.
My problem is as the fire burns down, when it gets down to just a few ashed over coals, with the damper closed I end up with carbon monoxide coming into the room.

My setup:

Drolet 1800 insert with distribution fan
6 inch insulated stainless liner - approximately 21 feet from top of insert to top of liner
Liner cap in place with 6 inches of clearance for exhaust
Fireplace is brick with a terra cotta liner in good shape that the liner runs through
No fresh air intake (house built in 1997)
Fireplace is in a den, approximately 200 sq feet, monoxide detector on opposite wall reads 0 when burning, 158 when burning out

Any help would be appreciated

 

[begreen]

This sounds like draft reversal. Is there a device or appliance or heater exhausting or consuming combustion air that is coming on at the time of the high reading? As a test, does leaving a nearby window open 1/2" during the late stage of the burn help prevent the high reading?

 

[Mmeade]

I had a pellet stove running on the other side of the house that doesn’t have a fresh air intake. 50 feet away or so? Would that pull that much air to cause an issue?

 

[begreen]

If the house is pretty tight, then yes there is a possibility that the pellet stove is creating a slight negative pressure when running. In this case, open a window close to the pellet stove 1/2" and see if that stops the issue. If so, add an OAK to the pellet stove.

Is this a one or two-story home? If 2, another thing to check would be air leaks (attic hatch, or door, or vent) or a window slightly open or leaking on the second floor.

 

[Mmeade]

If the house is pretty tight, then yes there is a possibility that the pellet stove is creating a slight negative pressure when running. In this case, open a window close to the pellet stove 1/2" and see if that stops the issue. If so, add an OAK to the pellet stove.

Is this a one or two-story home?

I had an OAK on the pellet stove before, simple enough to add back on and try again…2 story home

 

[kborndale]

I had an OAK on the pellet stove before, simple enough to add back on and try again…2 story home

Just curious, if you had an oak before, why would you remove it?

 

[begreen]

I had an OAK on the pellet stove before, simple enough to add back on and try again…2 story home

Definitely reconnect the pellet stove oak and see if that cures the issue. And make sure there are no air leaks or open windows on the second floor.

 

[Mmeade]

Just curious, if you had an oak before, why would you remove it?

I had a combo thimble, exhaust and OAK, and nice had built a nice home in the intake part, thus resulting in decreased airflow, so I just eliminated it from the equation

 

[Mmeade]

I have a combo thimble, exhaust and OAK, and mice had built a nice home in the intake part, thus resulting in decreased airflow, so I just eliminated it from the equation