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Note: Pressure Relief Valve is not included and has to to be purchased separately in order to properly install unit.

Think Green, Save Green. Rebate and incentive programs provide cash-back to consumers for the purchase of appliances that meet certain energy efficiency standards. Most states are offering rebates in the $50 to $250 range. You can search for rebates in your area from here.

The TK-540P-NEH heater integrates a recirculation pump to provide instant hot water in residential applications with dedicated recirculation lines. The pump is easily controlled with a simple user interface and multiple pump settings allow you to customize pump operation to meet your needs while maximizing heater efficiency. As part of the high efficiency tankless family, the 540P series provides endless hot water while being environmentally friendly.

The TK-540P-NEH outdoor tankless water heater uses up to 199,000 BTU/hr of natural gas to deliver an endless supply of hot water for a 3 bath home in northern climates and a 4 bath home in southern climates. It is built with commercial grade materials like marine-grade 316L stainless steel giving it an industry-leading warranty.

  • ENERGY STAR® qualified
  • 15-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Residential applications
  • 6-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Commercial applications
  • Integrated Recirculation Pump - 1/2" pipe - 100'; 3/4" pipe - 500'
  • Primary heat exchanger is constructed of a commercial grade copper that is more resilient to erosion.
  • Secondary heat exchanger is made of type 316L stainless steel to protect against corrosion.
  • Complies with Ultra-Low NOx regulations of less than 14 ng/J (<20ppm)
  • Easy-Link with up to three other T-H3 units to increase flow capacity
  • Condensing Outdoor model
  • Safety features include Air-Fuel ratio (AFR) sensor, freeze protection, overheat cut-off fuse, exhaust & water temperature safety control, and troubleshooting diagnostic codes
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3-5 Showers


Product Type:

Tankless Heater

Fuel Type:

Natural Gas

Vent Type:

Direct Vent

Power Vent

Installation Type:

Outdoor Only

Vent Size:



BTU (Max):


BTU (Min):


Water Connection:


Max Flow (GPM):



Ultra Low NOx

Energy Star Rated:




Energy Factor:




Flow Rate at 40F Temp Rise (GPM):


Flow Rate at 50F Temp Rise (GPM):


Flow Rate at 60F Temp Rise (GPM):


Flow Rate at 70F Temp Rise (GPM):


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