Who requires this opening of venting 18 " off the floor and ceiling, not
my furnace lennox. Ive never heard of a house having this open vent to
outdoors set up. My apt building with a 1.6 million btu boiler has a
window cracked 1" and the flame is adjusted by a tech with a Bachrach
set up and he says oxygen, color and burner efficiency are tops. boiler
is in a small room, heats 16 units steam heat. Infiltration does the
rest.