Overview
Specifications
| Heat Capacity (Input) | Natural Gas | 10,000 - 150,000 BTU/h (2.93 – 43.95 kWh) |
| Propane | 10,000 - 150,000 BTU/h (2.93 – 43.95 kWh) |
|
| Efficiency Ratings | UEF (NG & LP) | 0.95 |
| Flow Rate (DHW) | 35 ºF temp rise | 8.4 GPM (31.8 l/min) |
| 45 ºF temp rise | 6.5 GPM (24.6 l/min) | |
| 67 ºF temp rise | 4.3 GPM (16.3 l/min) |
| Dimensions | 17.3" W x 27.4" H x 13.2" D (43.9 cm W x 69.6 cm H x 33.5 cm D) |
| Boiler Weight | 73 lbs (33.1 kg) |
| Installation Type | Indoor or outdoor wall-hung |
| Ignition | Electronic ignition |
| Water Pressure | 15-150 PSI (1.055 – 10.545 kg/cm2)) |
| Natural Gas Supply Pressure (from source) |
3.5" WC to 10.5" WC (0.87 Kpa to 2.61 Kpa) |
| Propane Gas Supply Pressure (from source) |
8″ WC to 13″ WC (1.99 Kpa to 3.23 Kpa) |
| Natural Gas Manifold Pressure (min-max) |
-0.03″ WC to -0.55″ WC (-0.0075 Kpa to -0.14 Kpa) |
| Propane Gas Manifold Pressure (min-max) |
-0.2″ WC to -0.55″ WC (-0.005 Kpa to -0.14 Kpa) |
| Minimum Flow Rate | 0.5 GPM (1.893 l/m), <0.01 GPM (0.04 l/m) option* |
| Connection Sizes | Cold Water Inlet | 3/4" |
| Hot Water Outlet Size | 3/4" | |
| Gas Inlet | 3/4" | |
| Power Supply | Main Supply | 120V AC, 60 Hz |
| Maximum Power Consumption | 200 W (max 2 A), 350 W (max 4 A) with external pump connected | |
| Materials | Casing | Cold rolled carbon steel |
| Heat Exchangers | Primary heat exchanger: stainless steel Secondary heat exchanger: stainless steel |
|
| Venting | Exhaust | 2″ or 3″ PVC, CPVC, approved polypropylene and stainless steel 2″ or 3″ special gas vent type BH (Class II, A/B/C) |
| Intake | 2″ or 3″ PVC, CPVC, approved polypropylene and stainless steel 2″ or 3″ special gas vent type BH (Class II, A/B/C) | |
| Vent Clearances | 0″ to combustibles |
| High Elevations | 10,100 feet for both NG or LP gas. Please refer to installation Manual for additional details and instructions. |
| Safety Devices | Flame rod, APS, ingnition operation detector, water temperature high limit switch, exhaust temperature high limit sensor, power surge fuse, burner high limit fuse, vent installation detector (VID) |
* Available for NPE-A2 models configured in an optional ComfortFlow® recirculation mode. Energy consumption will increase when the system is configured for recirculation.
Dimensions
| Width | 17.3" (43.9 cm) |
| Height | 27.4" (69.6 cm) |
| Depth | 13.2" (33.5 cm) |

Connection Sizes
| (A) Air intake | 2" |
| (B) Exhaust Gas Vent | 2" |
| (C) Hot Water Outlett | 3/4" |
| (D) Gas Inlet | 3/4" |
| (E) Recirculation Inlet | 3/4" |
| (F) Condensate Outlet | 1/2" |
| (G) Cold Water Inlet | 3/4" |


Certification Summary
All NPE-2 models are field convertible from NG to LP gas.
Product Approvals
| CSA | Yes |
| NSF (Standard 5) | Yes |
| Low Lead (<0.25%) | Yes |
| SCAQMD 1146.2 (NOx, <20ppm) | Yes |
| AHRI Number | 206368357 |
| Energy Star Certified | Yes |
Efficiency Ratings*
| Uniform Energy Factor (UEF) | 0.95 |
| MAX GPM (67 ºF Rise) | 4.3 GPM (16.3 l/min) |
Annual Energy Consumption* (Residential)
| Natural Gas (Therms/Year) | 179.0 |
| Propane (Gallons/Year) | 196 gal (741.9 L) |
| Natural Gas Estimated Operating Cost** | $195 |
| Propane Estimated Operating Cost** | $472 |
* Based on U.S. Department of Energy (DOE) test procedures.
** Based on a national average natural gas cost of $1.09/therm, propane cost of $2.41/gallon.
Certifications / Qualification

Temperature Rise
| Temperature Rise | NPE-180A2 |
| 35 ºF (19.4 ºC) rate | 8.4 GPM (31.8 l/min) |
| 40 ºF (22.2 ºC) rate | 7.4 GPM (28 l/min) |
| 45 ºF (25 ºC) rate | 6.5 GPM (24.6 l/min) |
| 50 ºF (27.8 ºC) rate | 5.9 GPM (22.3 l/min) |
| 55 ºF (30.6 ºC) rate | 5.3 GPM (20.1 l/min) |
| 60 ºF (33.3 ºC) rate | 4.9 GPM (18.5 l/min) |
| 65 ºF (36.1 ºC) rate | 4.5 GPM (17 l/min) |
| 70 ºF (38.9 ºC) rate | 4.2 GPM (15.9 l/min) |
| 75 ºF (41.7 ºC) rate | 3.9 GPM (14.8 l/min) |
| 80 ºF (44.4 ºC) rate | 3.7 GPM (14 l/min) |
| 85 ºF (47.2 ºC) rate | 3.5 GPM (13.2 l/min) |
| 90 ºF (50 ºC) rate | 3.3 GPM (12.5 l/min) |
| 100 ºF (55.6 ºC) rate | 2.9 GPM (11 l/min) |
| 110 ºF (61.1 ºC) rate | 2.7 GPM (10.2 l/min) |
| 120 ºF (66.7 ºC) rate | 2.5 GPM (9.5 l/min) |
| 130 ºF (72.2 ºC) rate | 2.3 GPM (8.7 l/min) |
| 140 ºF (77.8 ºC) rate | 2.1 GPM (7.9 l/min) |
DHW Capacity
| Model | NPE-180A2 |
| Natural Gas | 10,000 - 150,000 BTU/h (2.93 - 43.95 kWh) |
| Propane | 10,000 - 150,000 BTU/h (2.93 - 43.95 kWh) |
Operating Cost
| Navien Tankless | 179.0 therms | $195* |
| Other Tankless | 228 therms | $249 |
| 50 Gallon Tank | 293 therms | $319 |
* Based on Energy Guide cost estimates using $1.09 per therm of natural gas. Cost is in US dollars.
