Quadrafire 7100 FP question

[Greg D]

Hi all,

I had a question regarding our Quadrafire 7100 FP. As each load of wood nears the end of its burn cycle, and when I re-load, I feel cold air blowing in directly under the handles for the doors. If I turn the outside combustion air knob (on the right side) to the "closed" position, I hear the flap close and this draft stops.

I think the manual says that while burning, the knob should be in the "open" position. Our house is spray foam insulated and very tight, so this cold draft is annoying. It seems that our family room where the insert is located should sustain higher temps during the overnight burn if this cold draft was minimized. What would be the negatives for burning with this knob in the closed position? Or is there some kind of temperature sensitive mechanism that could close the flap when the fire is cooler and open it when the fire is producing enough heat?

Other than this small gripe, we are staying warm durning this long winter, using about half as much wood as I used last year (the power of seasoned wood).

Thanks.

Greg

 

[Village Idiot]

I experience the same thing when I let the fireplace get cold. As long as it has some residual heat in it, that cold air flow doesn't happen.

I am not aware of any mechanism that would close the flap automatically, but it would be great. There are times when we are going to be away all day and I debate with myself the merits of leaving the flap open to use outside air for combustion and the cold air that will come in once the fireplace is cold or closing it and using the inside air and the associated cold makeup air that will be drawn into the house. (With your foam insulation, your house is surely tight and I cannot speak to the amount of makeup air that can get in.) I have tried both and have not arrived at a definitive answer.

Though, I do know we can be grateful that we were not among the early adopters of the 7100. The first units did not have the air knob and flap. It was open all the time. QuadraFire came out with a retrofit kit to add the knob and flap. I read that they originally figured that the fireplace would be burning full time and the cold air infiltration would not be an issue. Glad they fixed it.

 

[Greg D]

I experience the same thing when I let the fireplace get cold. As long as it has some residual heat in it, that cold air flow doesn't happen.

I am not aware of any mechanism that would close the flap automatically, but it would be great. There are times when we are going to be away all day and I debate with myself the merits of leaving the flap open to use outside air for combustion and the cold air that will come in once the fireplace is cold or closing it and using the inside air and the associated cold makeup air that will be drawn into the house. (With your foam insulation, your house is surely tight and I cannot speak to the amount of makeup air that can get in.) I have tried both and have not arrived at a definitive answer.

Though, I do know we can be grateful that we were not among the early adopters of the 7100. The first units did not have the air knob and flap. It was open all the time. QuadraFire came out with a retrofit kit to add the knob and flap. I read that they originally figured that the fireplace would be burning full time and the cold air infiltration would not be an issue. Glad they fixed it.

Thanks for the response! So other than pulling heated air from inside the house to use for combusition, is there any other downfall to burning with the outside air closed?

Just curious- do you prefer to burn N/S or E/W in your 7100?

 

[Village Idiot]

You said you have foam insulation, so that means you should be pretty tight. But, the makeup air has to come from somewhere. It will get pulled through any crack it can. I have read that in a well sealed house, even running the exhaust fan over the stove can de-pressurize the house and cause performance issues with burning.

I have essentially just learned to live with it and will flip the flapper closed if I think cold air will be an issue.

As for how I burn, I load to get as much wood in as possible. I scrounge all of my wood, so I cannot control the length of the pieces. So I tend to do E/W on the right side and N/S on the space left on the right. Overall, I don't get too hung up over how I load. As long as I am feeding in well seasoned wood, ,y goal is to extract as many BTUs as I can over a decent number of hours.