I installed a Napoleon 1401 basically the same insert except my secondary manifold is welded in place and your fan shrouds are prettier. I installed it my self the fireplace and chimney was very clean like it only burnt gas, so cleaning was a breeze, check the smoke shelf for leaves and debris. Cutting out the damper was quick maybe 20 minutes with a sawsall and had to knock out the top row of fire brick, I used a small sledge hammer. The bricks will usually come out whole if you break the mortar joints. If you have an ash dump or air inlet for the fireplace you will want to seal that off I place sheet metal over mine. I would make the block off plate before you install the insert have it ready to go in, use cardboard for a template. I used lightweight liner approximately 18' I was able to feed it in myself standing on top of the chimney while I had help pulling it down. If you don't want to buy a pulling cone you can make a ball out of old plastic shopping bags and tape that in the open end, pull the stainless mesh over your insulation together and tie a guide rope on that so some one can pull to guide it down the flu.
The 1402/ 1401 sits out on the hearth so you liner will be close to the front of the fire place it makes it a little rough to connect to the insert. I used 3 "L" brackets to hold the appliance adapter to the insert, I attached The" L's" first then screwed through them into the liner. I then fastened my block off plate in place with the liner coming through the hole, make sure you cut the hole 1/2 to 3/34 inch larger to give the liner wiggle room, you can always place some insulation around the gap. To get the liner and adapter seated all the way in the flu collar I had to tilt the insert back towards the fireplace. I placed boards under the front edge tilting the top until it hit the bricks on the sides, let it down slowly, you don't want to damage the liner. You will have to work the liner a bit to get it set where you want it.
I am very happy with my stove usually 9 hours on a burn glass stays pretty clean and will usually burn any soot off on it own when it gets hot. When the secondary kick it good you will see a really cool twin counter rotating vortex in the top its unlike any stove I have seen before, then followed by the lazy blue flames. Hop it goes well and enjoy.
