[1retired06]

I installed the combo in both our 3655 and our 3910. Not a difficult job, does require some muscle. Agree, install must be on the floor not a shelf. Do not trust the decal for the vent, it was way off on the 3910. Mark a spot that is the most direct shot from the back of the unit to the wall, and then make sure that spot is clear of electrical, wall studs. Biggest headache I had was getting the unit over the lip across the cabinet floor entrance, ended up with a ramp setup. It was tight, I had to get 90 degree elbows in order to get to the water hookups, and vent hose was a PITA as I wanted it as short as possible. We got the combo in by putting two come-along straps underneath the unit and sliding it over the ramp and into the pan and two thirds of the way in, doing the vent hookup. I removed the shelf for the install, and replaced it with 1/2 plywood stained to match, and cut it into two pieces, which allows me to lift the back piece off and have easy access the back of the combo if necessary. To ensure I did not screw up the 4 inch wall cut, I first checked with my studfinder, marked the hole, using my smallest bit drilled holes at the 12, 3, 6, and 9 locations plus the center. I also started the cut on the inside, and when my holesaw penetrated the outerwall, finished the cut from the outside in. Did have to remove the stair rail to get the unit up the steps.