Sign In to View Pricing & Availability
- Ultra-Low NOx gas tankless water heaters with condensing technology featuring an unprecedented 0.95 Energy Factor which lowers operating costs and is environmentally friendly.
Looking for model-specific repair or replacement parts? Enter the unit’s serial number into the A.O. Smith Parts Finder.
A.O. Smith® Tankless Water Heater, Series: ATI-540H, 199000 Btu/hr Heating, Liquid Propane, 3/4 in NPT Gas Connection, Electronic Spark Ignition, Power Direct Vent, 3 in, 4 in Vent, Condensing/Non Condensing: Condensing, 10 gpm, 0.95, 3/4 in NPT Water Connection, 15 to 150 psi, Ultra Low NOx: Yes, Indoor/Outdoor: Indoor, 17-3/4 in W x 11-1/4 in D x 23-5/8 in H, Dual
- The ATI-540H-P tankless water heater uses up to 199000 Btu/hr of liquid propane to deliver an endless supply of hot water for a 3 bath home in northern climates and up to a 4 bath home in southern climates (one shower head per bath)
- Easy link up to 4 heaters
- Multi-link up to 20 heaters
- Air fuel ratio (AFR) sensor
- Exhaust and water temperature safety control
- Overheat cut-off fuse
- Provides flexible venting with PVC, CPVC or ABS pipe for intake and exhaust (solid core only)
- Category III or IV venting can be used
- Certified from sea level to 10100 ft elevation
- Indoor model - Built-in temperature controller and advanced diagnostics to simplify troubleshooting
- Integrated Temperature Controls and Advanced Diagnostics to Simplify Troubleshooting
- Commercial / Residential / DualDualEnergy Factor0.95Flow Rate10 gpmFuel TypeLiquid PropaneHeating Capacity199,000 BTU/hrIndoor / OutdoorIndoorUltra Low NOxYesVent Size3 in, 4 inVent TypePower DirectCondensing / Non-CondensingCondensingDimensions23-5/8 in H x 17-3/4 in W x 11-1/4 in DGas Connection3/4 in NPTIgnition TypeElectronic SparkManufacturerA.O. SmithManufacturer #ATI-540H-PMaterial316L Stainless Steel/CopperPressure Rating8 to 14 psiSeries540TypeHigh-EfficiencyWater Connection3/4 in NPT