American Tankless Water Heater

If looking to buy a product with on demand water heating, American tankless water heater, made by an American WH Company and owned by AO Smith Corporation, might be a solution for you. See why...

What should you know when buying American tankless

The main reasons for buying an American are the Energy Star compliance and energy savings, an endless supply of hot water, on demand water heating at the preset temperature and the recognized name. For the review of the most advanced features and benefits read further.


American tankless water heater can be found in six categories, designed for residential and light duty commercial water heating (below are the new and old models). They come with different capacities, power range and installation options. All of them are wall mounted, some are direct vented units for indoor use while other are for the outdoor installation and they do not require venting.

The main advantages of the American tankless heaters over storage tank type models are the continuous supply of hot water, technology that works on demand and when it is needed; and plenty of hot water for the whole house use.

american tankless water heaterAmerican tankless water heater is the energy efficient gas unit with 84% thermal efficiency and high performance level; it reduces the energy loss and increases money savings. All models are Energy Star compliant, and with a high efficiency they are eligible for rebates.

Standard equipment like direct electronic ignition (no pilot light and waste of gas) and accurate remote temperature control of +/-2 F are also helping in reducing energy waste.

Temperature remote controller is included with 510 models and is very convenient feature. It allows you to set the temperature, monitor the operation and check if something is wrong with the heater, when the error code flashes.

Every American tankless water heater is using natural gas, which is factory set option, but can be easily converted to use propane gas. The efficient gas burner was designed to produce less NOx gases, which makes these water heaters environment friendly or "green".

Indoor models are direct vent and combustion sealed, so the outside air is drawn inside the chamber while inside air is protected of being used. At the same time the flue gases, as products of combustion, are forced out through the venting system. The venting pipes can be directed either horizontally or vertically, which adds even more flexibility in the installation.

Every American tankless water heater that is built for the residential use come with the 12-year limited warranty on heat exchanger and 5-year warranty on parts. They are used not only for potable water heating, but in hydronic heating, radiant floor heating, recirculation and combination of domestic and heating applications.

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Models and Specifications

  • GT-110 -NI and GT-110 -NE are indoor and outdoor models that are used for residential and light commercial applications, as the models 310 and 510 below. Fully modulating gas blower is a standard feature for every American tankless water heater and for these models it works in a range from 19,500 to the maximum of 140,000 Btu. The heaters are providing maximum of 6.6 gallons per minute of hot water which makes them good for 1-2 bath homes.

  • GT-310-NI is an indoor direct vent while GT-310-NE is the outdoor model, both designed with the gas input from 11,000 to 190,000 Btu and maximum water flow of 8.0 GPM, which is perfect for 2-3 bath homes.

  • GT-320-NIH and GT-302-NEH are the high efficiency and condensing tankless water heater that use two heat exchangers for more efficient heating and energy savings. As the previous models, they produce maximum hot water of 8.0 GPM but have slightly different gas inputs; 13,000 for the minimum and 180,000 for the maximum and higher energy factor of 0.91. They are equipped with the LCD display which shows the temperature and the error codes for easy troubleshooting.

  • GT-510-NI and GT-510-NE have the minimum Btu input of 11,000 and maximum of 199,000, and the water flow reaches high 10 GPM. Without using the additional accessories these models can be linked to up to 4 units for home with a higher demand.

  • GT-520-NIH and GT-520-NEH are condensing and tankless water heaters that are able to provide high energy efficiency (EF is 0.91) and 9 GPM hot water flow rate in continuous supply. A convenient built-in display shows the temperature and error codes. Easy-Link allows up to 4 units to be connected and work as one.

  • American tankless water heater from GT-305 series is designed to work with min 15,000 BTU/h and max. 180,000 BTU/h gas input, providing maximum of 7.5 GPM of hot water. With energy factor, EF of 0.82, 305 models are Energy Star qualified.

  • Models GT-505 are designed to work within the range of min 15,000 BTU/h and max. 199,000/190,000 (propane) BTU/h gas input, providing maximum of 9.4 GPM of hot water. With energy factor, EF of 0.82, 505 models are Energy Star qualified.

  • American tankless models GT-705 are designed to work with min 19,000 BTU/h and max. 237,000 BTU/h of gas, providing maximum of 9.8 GPM of hot water. 705 models are not Energy Star considered as the rule applies only on units up to 199,000 BTU/h.


  • Heat exchanger

  • Heat exchanger thermistor or over-heat switch

  • Gas burner

  • Spark electrode and flame rod (it proves ignition)

  • Flue outlet

  • Combustion fan - when it is energized, it purges the combustion chamber.

  • Solenoid valves

  • Thermal fuse

  • PC board - monitors inlet and outlet water temperature inside the tankless water heater, flow rate, flame rod, fan motor frequency...

  • Frost sensing switch

  • Modulating gas control valve - modulates gas input to required value.

  • Water flow device and sensor - send pulses to PCB when minimum water flow is established.

  • Water inlet and outlet

Safety Features

  • Overheating system shuts the tankless water heater automatically if there is an excessive temperature rise, much higher that the pre-set temperature.

  • If the above overheating system fails, a fusible link will break, shutting off the unit.

  • Flame failure system is used to shut the system off if the burner flame is not present.

  • If there is a situation with power failure, the water heater will cut off the gas automatically.

  • In a case of over-current, the power surge glass fuse will blow and shut the tankless water heater off.

  • Freeze protection that includes electrical heating elements and intermittent firing of the burner.

Note: Keep in mind that a minimum flow rate of 0.6 GPM and min. pressure of 20 PSI has to be provided for normal performance, for any American tankless water heater.

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(All pictures are courtesy of American)