| Heat Capacity (input) (Natural gas) | 13,300 - 199,900 BTU/h |
| Heat Capacity (input) (Propane) | 13,300 - 199,900 BTU/h |
| Efficiency ratings (UEF (NG & LP)) | 0.96 |
| Flow rate (DHW) (35°F temp rise) | 11.2 GPM |
| Flow rate (DHW) (45°F temp rise) | 8.7 GPM |
| Flow rate (DHW) (67°F temp rise) | 5.8 GPM |
| Minimum flow rate | 0.5 GPM |
| Connection sizes (Cold water inlet) | 3/4" NPT |
| Connection sizes (Hot water outlet size) | 3/4" NPT |
| Connection sizes (Gas inlet) | 3/4" NPT |
| Water pressure | 15-150 PSI |
| Natural gas supply pressure (from source) | 3.5 " WC to 10.5 " WC |
| Propane gas supply pressure (from source) | 8 " WC to 13 " WC |
| Natural gas manifold pressure (min-max) | -0.03 " WC to -0.96 " WC |
| Propane gas manifold pressure (min-max) | -0.02 " WC to -0.96 " WC |
| Power supply (Main supply) | 120V AC, 60 Hz |
| Power supply (Maximum power consumption) | 200 W (max 2 A), 350 W (max 4 A) with external pump connected |
| 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) |
| Venting (Intake) | 2" or 3" PVC, CPVC, approved polypropylene and stainless steel 2" or 3" special gas vent type BH (Class II, A /B/C) |
| Venting (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. |
| Dimensions | 17.3" W x 27.4" H x 13.2" D |
| Boiler weight | 73 lbs |
| Materials (Casing) | Cold rolled carbon steel |
| Materials (Heat exchangers) | Primary heat exchanger: stainless steel Secondary heat exchanger: stainless steel |
| Safety Devices | Flame rod, APS, ignition operation detector, water temperature high limit switch, exhaust temperature high limit sensor, power surge fuse, burner high limit fuse, vent installation detector (VID) |
| AHRI number | 206368362 |
| Energy star certified | Yes |
| CSA | Yes |
| NSF (Standard 5) | Yes |
| Low Lead (<0.25%) | Yes |
| SCAQMD 1146.2 (NOx, <20ppm) | Yes |
- NPE-2 Specification Sheet PDF ↗
- NPE-2 Installation & Operation Manual PDF ↗
- NPE-2 User's Information Manual PDF ↗
- NPE-2 Commercial Application Guide PDF ↗
- NPE-2 High Altitude Conversion Guide PDF ↗
- NPE-2 LP Gas Conversion Guide PDF ↗
- NPE-2 Quick Installation Guide PDF ↗
- NaviLink Lite Wi-Fi Control Spec Sheet PDF ↗
Description
The Navien NPE-240S2 is a condensing tankless water heater from Navien's NPE-2 series. Same cabinet and the same pair of stainless steel heat exchangers as the NPE-240A2, without the internal pump — which is why it carries the higher efficiency rating of the two.
Rated input is 13,300 - 199,900 BTU/h on natural gas or propane — the unit is certified for both. It modulates from 199,900 BTU/h all the way down to 13,300, so it is not running at full fire to fill a sink.
How much hot water you actually get
Navien rates every tankless unit by temperature rise, because the colder the incoming water, the less of it one burner can heat. Here is what the NPE-240S2 delivers:
| Temperature rise | Flow rate | Typical use |
|---|---|---|
| 35°F | 11.2 GPM | Warm-climate groundwater, or a preheated feed |
| 45°F | 8.7 GPM | The usual design point across most of the U.S. |
| 67°F | 5.8 GPM | Northern winter, incoming water near 40°F |
Sized against a 2.5 GPM showerhead, the 67°F column is worth roughly 2 showers at once on the coldest day of the year, and more than that the rest of the year. Size to the 67°F row if your winter groundwater runs cold.
Minimum activation flow is 0.5 GPM, so it fires for a hand wash, not just a full shower.
Installing it
- Cabinet: 17.3" W x 27.4" H x 13.2" D
- Weight: 73 lbs
- Water connections: 3/4" NPT cold in, 3/4" NPT hot out
- Gas connection: 3/4" NPT
- Water pressure range: 15-150 PSI
- Power: 120V AC, 60 Hz
- Venting: 2" or 3" PVC, CPVC, polypropylene or stainless steel, intake and exhaust
- Vent clearance: 0" to combustibles
- Altitude: approved to 10,100 feet for both NG or LP gas. See the installation manual for the details.
- Heat exchanger: dual stainless steel, primary and secondary
Ratings and certifications
- UEF: 0.96
- ENERGY STAR® certified
- CSA certified
- NSF Standard 5
- lead free (<0.25%)
- SCAQMD 1146.2 low-NOx (under 20 ppm), the rule that governs Southern California
- AHRI: 206368362
Model details
- Brand: Navien
- Manufacturer part number: NPE-240S2
- UPC: 884954920894
Ships in the manufacturer's carton. Shipping is calculated at checkout by weight, dimensions and destination. Gas connection, venting and condensate disposal must be done by a licensed installer, to the Navien manual and to your local code.