boilers AGA Input Rating 100 MBH . 100000 BTU Hour . 125 MBH . 125000 BTU Hour . 150 MBH . 153000 BTU Hour, 125000 BTU Hour . 164000 BTU Hour . 170000 BTU Hour . 187000 BTU Hour, 175000 BTU Hour . 200 MBH .. in the past