A. O. Smith Water Heater Manuals
Select your A. O. Smith model number below for installation steps, settings, maintenance schedules, troubleshooting and the full specification sheet. Your model number is printed on the rating plate.
A. O. Smith water heaters by model number
| Model | Description | Certified |
|---|---|---|
| ACT-199O-N 1T-H3-OS-N 1** | 199,000 Btu/h natural gas tankless water heater | February 2023 |
| ACT-199O-P 1*1T-H3-OS-N 1** | 199,000 Btu/h propane tankless water heater | February 2023 |
| ACTH-199M-(N,P) 1 | 199,000 Btu/h gas tankless water heater | July 2026 |
| ATHR-160M 1 | 160,000 Btu/h gas tankless water heater | December 2023 |
| ATHR-160X3 1ATHR-160M 1** | 160,000 Btu/h gas tankless water heater | December 2023 |
| ATHR-180M 1 | 180,000 Btu/h gas tankless water heater | December 2023 |
| ATHR-180X3 1ATHR-180M 1** | 180,000 Btu/h gas tankless water heater | December 2023 |
| ATHR-199M 1 | 199,000 Btu/h gas tankless water heater | December 2023 |
| ATHR-199X3 1ATHR-199M 1** | 199,000 Btu/h gas tankless water heater | December 2023 |
| ATI-340H 1T-H3S-DV-N | 180,000 Btu/h natural gas tankless water heater | February 2023 |
| ATI-340H 1*1T-H3S-DV-N | 180,000 Btu/h propane tankless water heater | February 2023 |
| ATI-340HX3-N 1T-H3S-DV-N | 180,000 Btu/h natural gas tankless water heater | February 2023 |
| ATI-340HX3-P 1*1T-H3S-DV-N | 180,000 Btu/h propane tankless water heater | February 2023 |
| ATM-140M-N 1 | 140,000 Btu/h natural gas tankless water heater | July 2026 |
| ATM-140X3-N 1ATM-140M-N 1** | 140,000 Btu/h natural gas tankless water heater | July 2026 |
| ATM-160M-N 1 | 160,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-160M-P 1*1 | 160,000 Btu/h propane tankless water heater | July 2026 |
| ATM-160X3-N 1ATM-160M-N 1** | 160,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-160X3-P 1*1 | 160,000 Btu/h propane tankless water heater | July 2026 |
| ATM-180M-N 1 | 180,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-180M-P 1*1 | 160,000 Btu/h propane tankless water heater | May 2026 |
| ATM-180X3-N 1ATM-180M-N 1** | 180,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-180X3-P 1*1 | 160,000 Btu/h propane tankless water heater | May 2026 |
| ATM-199M-N 1 | 199,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-199M-P 1*1 | 160,000 Btu/h propane tankless water heater | May 2026 |
| ATM-199X3-N 1ATM-199M-N 1** | 199,000 Btu/h natural gas tankless water heater | April 2025 |
| ATM-199X3-P 1*1 | 160,000 Btu/h propane tankless water heater | May 2026 |
| ATO-240H 1T-H3J-OS-N | 160,000 Btu/h natural gas tankless water heater | February 2023 |
| ATO-240H 1*1T-H3J-OS-N | 160,000 Btu/h propane tankless water heater | February 2023 |
| ATO-240HX3-N 1T-H3J-OS-N | 160,000 Btu/h natural gas tankless water heater | February 2023 |
| ATO-240HX3-P 1*1T-H3J-OS-N | 160,000 Btu/h propane tankless water heater | February 2023 |
| ATO-540H 1T-H3-OS-N 1** | 199,000 Btu/h natural gas tankless water heater | February 2023 |
| ATO-540H 1*1T-H3-OS-N 1** | 199,000 Btu/h propane tankless water heater | February 2023 |
| ATO-540HX3-N 1T-H3-OS-N 1** | 199,000 Btu/h natural gas tankless water heater | February 2023 |
| ATO-540HX3-P 1*1T-H3-OS-N 1** | 199,000 Btu/h propane tankless water heater | February 2023 |
| ATO-540P-N 1T-H3-OS-N 1** | 199,000 Btu/h natural gas tankless water heater | February 2023 |
| ATO-540P-P 1*1T-H3-OS-N 1** | 199,000 Btu/h propane tankless water heater | February 2023 |
| CAHP-40 2 | 36-gallon heat pump water heater | August 2026 |
| CAHP-50 2 | 46-gallon heat pump water heater | August 2026 |
| CAHP-66 2 | 68-gallon heat pump water heater | August 2026 |
| CAHP-80 2 | 81-gallon heat pump water heater | August 2026 |
| FPTU-50 1 | 46-gallon heat pump water heater | February 2023 |
| FPTU-66 1 | 67-gallon heat pump water heater | February 2023 |
| FPTU-80 1 | 82-gallon heat pump water heater | February 2023 |
| GC6-PS4050*V 1 | 38-gallon natural gas storage water heater | February 2023 |
| GC6-PS5065*V 1 | 49-gallon natural gas storage water heater | February 2023 |
| GC9-PS4050NV 1GPCT-40L 1** | 38-gallon natural gas storage water heater | November 2024 |
| GC9-PS5065NV 1GPCX-50L 1** | 49-gallon natural gas storage water heater | March 2025 |