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T-H3-OS-NG 199,000 BTU Condensing Ultra-Low NOx Tankless Water Heater

T-H3-OS-NG 199,000 BTU Condensing Ultra-Low NOx Tankless Water Heater

T-H3-OS-NG 199,000 BTU Condensing Ultra-Low NOx Tankless Water Heater
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T-H3-OS-N or  T-H3-OS-NG  (199,000 BTU High Efficiency Condensing Ultra-Low NOx Outdoor Natural Gas Tankless Water Heater)
The T-H3-OS-NG Outdoor On Demand Endless Hot Tankless Water Heater is well suited for residential/ commercial applications such as small restaurants and beauty salons. Complies with Ultra-Low NOx regulations. Utilizing commercial grade copper alloy for the heat exchanger tubing, the money and energy saving T-H3-OS-NG condensing outdoor Natural Gas tankless water heater is also suitable for heavier residential usages such as space heating or domestic recirculation systems. Remote control included as a standard feature on Outdoor models. Certified up to 10,100 ft. altitude
Number of showers this unit can handle, depending on ground water temperature.

Warmer Climates 

Cooler Climates 


The T-H3-OS-NG outdoor condensing instant and endless hot on-demand tankless natural gas water heater supplies hot water to domestic hot water systems (directly or indirectly) which can be used with storage tanks, recirculation systems, hydronic heating systems, radiant floor systems, and/or domestic & heating applications.
  • ENERGY STAR® qualified
  • Maximum flow rate of 10.0 GPM at 35°F temperature rise (5.4 GPM at 70°F rise)
  • Primary heat exchanger utilizes commercial-grade copper alloy for 25 times better heat transfer than stainless steel
  • Secondary heat exchanger utilizes 316L stainless steel for better corrosion resistance
  • NSF certified for commercial applications
  • Complies with Ultra-Low NOx regulations of less than 14 ng/J (<20ppm)
  • Easy-Link up to four units without a Multi-Unit Controller
  • Multi-Link up to 20 units with a Multi-Unit Controller
  • Includes remote control as standard feature
  • Venting with Schedule 40 PVC, CPVC, PP, Category III stainless steel
  • Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes
  • 15-year limited heat exchanger, 5 yrs limited parts Residential use
  • 5-year limited heat exchanger, 5 yrs limited parts Commercial use

Tech Specs

Emissions: Ultra-Low NOx
Maximum BTUs: 199,000
Minimum BTUs: 19,500
Water Connection Location: Bottom
Water Connection: 3/4"
Flow Rate: 10.00
Heat Exchanger: Copper & Stainless
Voltage: AC 120V
UEF: 0.95
ENERGY STAR® Qualified: Yes
LEED Rating: 1.5
Remote Control: Yes
Technology: Condensing
Multilink: Yes

Dimensions & Venting

Height: 22.50"
Width: 17.75"
Depth: 10.75"
Product Weight: 59 lbs.
Vent Type: NA
Vent Size: NA