Sorry guys, I've been very busy (busy season for us chimney sweeps) and havent been reading the posts until now so I'll try to answer some questions.
The last post by Greg L explains why I did the fresh air intake (wery well said sir!) and yes, my house is only 5 yrs old and pretty tight. My brother sells Keystoker and we had discussed a fresh air intake several times. His concern was having cold outside air directly feeding the fire might "cool" the fire. Actually the exact opposite has occoured. Looks like the fire was starving for oxygen. It burns so well now that I only have to pins left (in each of the 3 groups) on the timer and still have the 2" of hot coals on idle. I may get it down to just one.
The fresh air intake is about 5' lower than the exhaust which is around the corner. The prevaling wind blows the exhaust away from the side of the house the intake is on, but it really would not matter much if at all if it were a lot closer. if any exhaust was to find its way to the intake area, it would be sucked into the intake and sent right back through the combustion blower and back out the exhaust. No more fumes in the basement, no more heat loss in the basement. Its 80 degrees down there right now with just the radient heat from the unit.
As for the way the duct is attached....well, it really isnt. I just have it stuck near the intake fan for the combustion motor and theres so much suction it just sticks to the wall with no need for an attachment! This is a perfect example of how much vacume the cumbustion motor creates.
As for heat circulation, I have the plenum connected right to the A/C distribution duct which has 7 registers throught the downstairs. I also have 2 "gates" installed in the ductwork for summer and winter operation. I have an access door on the return duct which when open allows the air to return through the return registers to the basement for perfect circulation without having to have the basement door open.
So far the temp upstairs (2nd flr) is only 2 or 3 degrees below the temp downstairs (1st flr). I have no vents going upstairs. Its just heat rising through the stairway.
If theres anything else anyone would like info on, please email me at email@example.com
Finally, I just fabricated a proper funnel to get the coal into my basement. See below .........