Armstrong International has introduced the Flo-Direct line of gas-fired water heaters. Flo-Direct has a top-mounted gas burner that fires downward through a centrally located flame tube. The resulting heat from the flame heats the falling water, which comes in contact with the bed of packing rings where heat transfer occurs. The hot gases and water are not separated by an exchanger wall, so scale in the unit is minimized. The water heater is made of stainless steel, and water temperatures from 130 degrees to 185 degrees F are available within 15-20 seconds of demand. A two-pass flow of hot gases ensures a 98% or greater fuel efficiency. Armstrong International.