- Air-Fuel ratio (AFR) sensor
- Exhaust and water temperature safety control
- Overheat cutoff fuse
- 12-year limited warranty on heat exchanger
Product Description
AO Smith ATO-520H-P Tankless Heater Condensing Residential/Light Commercial Propane Gas Outdoor Minimum 13,000 Btu Input Maximum 199,000 Btu Input Maximum GPM 9.0.
From the Manufacturer
AO Smith ATO-520H-P Tankless Heater Condensing Residential/Light Commercial Propane Gas Outdoor Minimum 13,000 Btu Input Maximum 199,000 Btu Input Maximum GPM 9.0.