On 12/25/2012 4:37 PM, Jim wrote:
Doug Miller wrote:

At least, remove them long enough to find out if the dampers operate
properly, and the fireplaces will draw properly with the unused one(s)
closed.

Thanks for the clarification on the damper.
I didn't know if the clamp was a safety feature or what.
I'll remove the clamnps to see what happens with the air.

If by "see what happens," you mean you're gonna instrument it
under different wind direction/speeds and fire conditions, that's great.
If not, make sure your CO detectors work and your exit strategy
is rehearsed.

My fireplace is capped, 'cause I don't use it.

The range vent hood can pull a 5 Pascal vacuum on the inside.

I'd be nervous about a smoldering fire with negative
pressure.