Gas Water Heater – NPE-150S

Max Input : 120,000 BTU/H
Indoor/Outdoor Installation

  • ½” gas pipe capable up to 24’
  • Field convertible gas system
  • Ultra condensing efficiency .97EF
  • Dual stainless steel heat exchangers
  • Low NOx emissions (≤ 20ppm)
  • SCH 40, 2” venting up to 60’
  • Cascading capable


Ultra Condensing Efficiency

  • Navien’s Condensing Technology offers the high efficiency.
  • Money and energy savings over tank type water heaters and traditional water heaters.

Two Stainless Steel Heat Exchangers

  • Provides longer life expectancy as they are highly resistant to corrosion and erosion compared to copper heat exchangers.
  • Reduces minerals deposits.

Low NOx Emissions (≤ 20ppm)

  • New metal fiber burner is designed to deliver a consistent air/gas mixture improving combustion efficiency.
  • Result in less acid rain and less green house effect.
  • Comply with SCAQMD 1146.2 strict NOx emissions standard.

2” PVC, CPVC, Polypropylene Venting Up To 60’

  • 2” venting option allows for a flue to be pulled through the existing vent.
  • 3” vents can be used up to 150’ with standard 2” x 3” adapters.

Utilizes Existing 1/2″ Gas Line

  • The negative pressure gas valve and fan with dual venturi operation allows for better adaptability to low gas pressure applications.
  • Makes it possible for the NPE to be installed ½” gas lines up to 24’.

Field Convertible

  • NPE models allow for easy convertibility from NG to LP.

Less Water Pressure Drop

  • Simple modular for water path minimizes water pressure drop.
  • Modular design for water path make maintenance easier and service can be performed easily in the field.


Data Field NPE-150S
Heat Capacity (Input) Natural Gas 18,000-120,000 BTU/H
Propane Gas 18,000-120,000 BTU/H
Efficiency Ratings UEF (for NG & LP) 0.96
EF (Canada) (for NG & LP) 0.97
Flow Rate (DHW) 35⁰F(19⁰C) Temp Rise 6.8 GPM (26 L/m)
45⁰F(25⁰C) Temp Rise 5.3 GPM (20 L/m)
67⁰F(36⁰C) Temp Rise 3.2 GPM (12 L/m)
Dimensions 17.3″(W) x 27.4″(H) x 13.2″(D)
Weight 55 lbs (25kg)
Installation Type Indoor or Outdoor Wall-Hung
Venting Type Forced Draft Direct Vent
Ignition Electronic Ignition
Water Pressure 15-150 PSI
Natural Gas Supply Pressure (from source) 3.5 in WC-10.5 in WC
Propane Gas Supply Pressure (from source) 8 in WC-13in WC
Natural Gas Manifold Pressure (min to max) -0.04 in WC to -0.38 in WC
-0.04 in WC to -0.42 in WC
Minimum Flow Rate 0.5 GPM (1.9 L/m)
Connection Sizes Cold Water Inlet 3/4 in NPT
Hot Water Outlet 3/4 in NPT
Gas Inlet 3/4 in NPT
Power Supply Main Supply 120V AC, 60Hz
Maximum Power Consumption 200W (max 2A), 350W (max 4A) with external pump connected
Materials Casing Cold Rolled Carbon Steel
Heat Exchangers Primary and secondary heat Exchangers: stainless steel
Venting Exhaust 2″ or 3″ PVC, CPVC, polypropylene 2″ or 3″ special gas vent type BH (Class II, A/B/C)
Intake 2″ or 3″ PVC, CPVC, polypropylene 2″ or 3″ special gas vent type BH (Class II, A/B/C)
Vent Clearances 0″ to Combustibles
Safety Devices Flame rod, APS, ignition operation detector, water temperature high limit switch, exhaust temperature high limit sensor, power surge fuse

Spec Sheet