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Navien NPE‑240S2 Ultra-Efficient Tankless Water Heater (with Professional Installation)

Navien NPE‑240S2 Ultra-Efficient Tankless Water Heater (with Professional Installation)

Navien NPE‑240S2 ultra-efficient tankless water heaters provide continuous hot water with ENERGY STAR® performance and low emissions.

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Navien NPE‑240S2 Ultra‑High Efficiency Condensing Tankless Water Heater

The NPE‑240S2 is part of Navien’s NPE‑S2 Series—ultra‑high efficiency condensing tankless water heaters designed for residential or light-commercial installations. All models support indoor or outdoor wall mounting, field gas convertibility, and are ENERGY STAR® certified.

Efficiency:

  • Uniform Energy Factor (UEF): 0.96 (Natural Gas or Propane)
  • ENERGY STAR® Certified for high performance and reduced energy costs

Performance:

  • Heat Input Range: 13,300 – 199,900 BTU/hr
  • Flow Rates:
    • 11.2 GPM @ 35 °F rise
    • 8.7 GPM @ 45 °F rise
    • 5.8 GPM @ 67 °F rise

Durability & Safety:

  • Dual stainless steel heat exchangers for corrosion resistance and long service life
  • Built-in safety features include flame sensor, overheat protection, freeze protection, fan motor rotation detector, and vent blockage detector

Installation & Features:

  • Indoor or outdoor wall-hung installation with vent lengths up to 75 ft (2″”) or 150 ft (3″”)
  • Supports ½”” gas piping up to 24 ft for retrofit compatibility
  • EZNav™ control panel with full text diagnostics and setup wizard
  • Ready-Link® system allows cascading up to 32 units or common venting up to 12 units

Plus:

  • Compact dimensions: 17.3″” W × 27.4″” H × 13.2″” D
  • Low NOx emissions — compliant with SCAQMD Rule 1146.2
  • Minimum flow rate: 0.5 GPM (operation down to 0.01 GPM with flow control accessories)

Warranty (Residential Installations):

  • 15-Year Limited Warranty on Heat Exchanger (when used without uncontrolled recirculation)
  • 5-Year Limited Warranty on Parts
  • 1-Year Limited Warranty on Labor

Note: Using uncontrolled external recirculation may reduce heat exchanger warranty to 5 years.

Learn more on the official product page:
Navien NPE‑240S2 Product Details

Item NPE‑240S2
Heat Capacity (Natural Gas) 13,300 – 199,900 BTU/h (3.9 – 58.57 kWh)
Heat Capacity (Propane) 13,300 – 199,900 BTU/h (3.9 – 58.57 kWh)
Efficiency (UEF) 0.96 (NG & LP)
Flow Rate @ 35°F Rise 11.2 GPM (42.4 l/min)
Flow Rate @ 45°F Rise 8.7 GPM (32.9 l/min)
Flow Rate @ 67°F Rise 5.8 GPM (22 l/min)
Dimensions (W x H x D) 17.3″” x 27.4″” x 13.2″” (43.9 cm x 69.6 cm x 33.5 cm)
Unit Weight 73 lbs (33.1 kg)
Installation Indoor or outdoor wall-hung
Venting Type Forced draft direct-vent
Ignition Electronic ignition
Water Pressure Range 15 – 150 PSI (1.05 – 10.55 kg/cm²)
NG Supply Pressure 3.5″” – 10.5″” WC (0.87 – 2.61 kPa)
LP Supply Pressure 8″” – 13″” WC (1.99 – 3.23 kPa)
NG Manifold Pressure -0.03″” – -0.96″” WC (-0.0075 – -0.24 kPa)
LP Manifold Pressure -0.02″” – -0.96″” WC (-0.005 – -0.24 kPa)
Minimum Flow Rate 0.5 GPM (1.9 l/min)
Cold Water Inlet Size 3/4″” NPT
Hot Water Outlet Size 3/4″” NPT
Gas Inlet Size 3/4″” NPT
Power Supply 120V AC, 60 Hz
Max Power Consumption 200 W (max 2 A), 350 W (max 4 A with external pump)
Casing Material Cold rolled carbon steel
Heat Exchangers Primary: Stainless steel
Secondary: Stainless steel
Exhaust Venting 2″” or 3″” PVC, CPVC, polypropylene or stainless steel (Class II, A/B/C)
Intake Venting 2″” or 3″” PVC, CPVC, polypropylene or stainless steel (Class II, A/B/C)
Vent Clearances 0″” to combustibles
High Elevation Limit Up to 10,100 ft (NG or LP)
Safety Devices Flame rod, APS, ignition detector, high-limit switches, exhaust sensor, surge fuse, burner fuse, vent installation detector (VID)

Bacon Wrapped Non-Circ Tankless Install – Turn Key Up To 4 Bath (Natural or Propane Convertible) Includes:

  • Frame to Retrofit
  • Gas Connection
  • Sediment Trap
  • Venting (No Roofer)
  • Service Kit
  • Water Ball Valve
  • Tankless Pan
  • Expansion Tank
  • Condensate Neutralizer
  • Permit and Inspection if Needed
  • Up To $650 In Rebates
  • Manufacturer Warranty: 15 Year Heat Exchanger, 5 Years Parts, 1 Year Labor*

*Ongoing membership to our Friends and Family Plan extends Parts and Labor coverage to 15 Years under the Bacon Wrapped No Hassle Warranty.

Note: Roofer not included. Add attic access if installation is above the first floor.