AO Smith ATO140HN Tankless Water Heater Condensing Outdoor 120,000 BTU Natural

Item#: ATO140HN

Brand: AO Smith

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Product Details
The 140H Series offers high efficiency Ultra-Low NOx condensing technology allowing for the use of 3” PVC venting and has 0” clearance to combustibles. Indoor models are certified up to 10,100 ft. altitude. Provides a variety of installation options: indoor, outdoor and direct vent. Complies with Ultra-Low NOx regulations and meets the energy efficiency requirements of ASHRAE 90.1b-1992.

The ATO-140H-N tankless water heater uses up to 120,000 BTUs of natural gas to deliver a max flow rate of 6.6 GPM. It utilizes condensing technology to achieve an Energy Factor of 0.93, and is ENERGY STAR qualified. this model meets Ultra-Low NOx emission requirements, and comes with a 15-year limited warranty.

How it Works

The comprehensive line of A. O. Smith tankless water heaters provide hot water on-demand.

• A hot water tap is opened 
• The opened tap allows water to flow through the water heater. An internal water flow sensor detects this flow 
• Upon flow detection, the flow sensor sends the activation signal to the computer board 
• The computer automatically ignites the burner 
• As water flows through the heat exchanger, it absorbs heat from the burner 
• By the time the water exits the heater, it has reached the designated set temperature 
• When the hot water tap is closed, the water heater automatically turns off

Product Specifications

Tech Specs
Emissions: Ultra-Low NOx
Maximum BTUs: 120,000
Minimum BTUs: 15,000
Limited Heat Exchanger Warranty: 15 Years
Limited Parts Warranty: 5 Years
Water Connection Location: Bottom
Water Connection Size: 3/4"
Heat Exchanger: Copper & Stainless
Secondary Heat Exchanger: Stainless Steel
Voltage: 120
Energy Factor: 0.93
Remote Control: Yes
Technology: Condensing

Dimensions & Venting
Type: Space Saving
Height: 22 7/8"
Width: 13 7/8"
Depth: 10 13/16"
Product Weight: 44lbs/20kg
Shipping Weight: 50lbs
Vent Material: PVC, CPVC, PP, ABS, SS

Product Features & Options

Dual Heat Exchanger

The primary heat exchanger is constructed of commercial-grade HRS35 copper, which is stronger than standard copper and more resilient against erosion. Condensing models feature 316L stainless steel secondary heat exchanger, providing additional protection against corrosion.

Space Savings

A. O. Smith tankless water heaters take up much less space that your conventional tank-style water heater. With no tank to steal valuable storage space, our wall-mount design allows for additional storage and flexibility.



Safety Features

Includes freeze, overheat, surge protection and troubleshooting diagnostic codes.


Endless Hot Water

The comprehensive line of A. O. Smith tankless water heaters are an excellent whole-home water heating solution that supply endless hot water.