Today I arrived on site AO Smith HWH 40 gal Installation: Returned to install AO Smith HWH for domestic hot water. Installation successfully completed. Equipment is operating correctly at this moment. We returned to install a new AO Smith HWH of 40 gal. I proceeded to cover the floor with drop clothes. We proceeded to disassemble the defective HWH. We disconnected the gas line, we disconnected the water lines, we disconnected the pipe. We proceeded to remove the existing tank. We proceeded to clean the work area. We proceed to put the HWH drain pan in its place. We put the new HWH in its place. I proceeded to connect the water lines of the tank. I proceeded to connect the gas line of the tank. I proceeded to connect the flue pipe. We made all the connections and adjustments necessary to complete the installation of the new HWH. We conclude with the installation of the new AO Smith HWH. We started the HWH inspection for gas leaks. No gas leaks present at this time. Inspect for CO leaka