If the duct is a standard size, remove the register and drop the fan into the boot. Secure it to the floor on each side with screws. If the duct is smaller than standard, see photos below. Plug the ...

QDEAR BARRY: My home has a forced-air heating system, with ducts installed beneath the concrete slab floor. When it rains for several days in a row, the vents get wet, and some have standing water in ...