The 540H is well suited for residential/commercial applications such as small restaurants and beauty salons. Utilizing HRS35 copper alloy for the heat exchanger tubing, the 540H is also suitable for heavier-residential usages such as space heating or domestic recirculation systems. Remote control included as a standard feature. Indoor models are certified up to 10,100 ft. altitude. Thicker heat exchanger drum and utilizes HRS35 (heat-resistant) copper for the heat exchanger tubing. Provides a variety of installation options: outdoor and direct vent. Includes a pump control port, ensuring efficient operation of all circulation pumps. Complies with Ultra-Low NOx regulations and meets the energy efficiency requirements of ASHRAE 90.1b-1992. Easy-Link System capable up to 4 units. Multi-Link System capable up to 20 units.
The ATO-540H-N tankless water heater uses up to 199,000 BTUs of natural gas to deliver a max flow rate of 10 GPM. It utilizes condensing technology to achieve an Energy Factor of 0.95, and is ENERGY STAR® qualified. This model meets Ultra-Low NOx emission requirements, and comes with a 15-year limited warranty.
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: |
199,000 |
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: |
HRS35 Copper Alloy |
Secondary Heat Exchanger: |
Stainless Steel |
Voltage: |
120 |
Energy Factor: |
0.95 |
ENERGY STAR®: |
Yes |
Remote Control: |
Yes |
Technology: |
Condensing |
Dimensions & Venting |
Type: |
Space Saving |
Height: |
23 5/8" |
Width: |
17 3/4" |
Depth: |
11 1/4" |
Product Weight: |
59lbs/27kg |
Shipping Weight: |
63lbs |
Vent Material: |
PVC, CPVC, PP, ABS, SS |