ao smith ati-340h-n 8 gpm residential/commercial condensing natural gas indoor tankless water heater with 180000 maximum btu input ao smith ao smith ati-340h 8 gpm residential/commercial condensing natural gas indoor tankless water heater with 180000 maximum btu input details: ati-340h never run out of hot water again with a steady 8 gpm flow rate conveniently mounts to your wall for a low profile installation features a built-in temperature controller and factory installed power cord can be used with either category iii or iv power direct venting in either a 3" or 4" size electronic ignition ensures you never have to mess with a pilot light again complies with lead-free standards vent material: pvc, cpvc, pp, abs, ss ultra low nox emissions yes protected by a multitude of built-in safety features such as an overheat cutoff fuse, constant temperature monitoring, and air fuel ratio rod durable heat exchanger is constructed of commercial-grade copper resulting in greatly increased heat transfer and resistance to erosion designed for indoor use only height: 23-5/8" width: 17-3/4" depth: 11-1/4" maximum flow rate: 8 gpm fuel type: natural gas energy factor: 0.95 max btu input: 180000 minimum input capacity 15000 btu voltage 120 volts phase 1 frequency 60 hz primary vent pipe diameter 4 inches gas connection size 3/4 inch cold water inlet 3/4 inch hot water outlet 3/4 inch maximum altitude 10100 feet designed for indoor use only