

Combination Boiler: Where Technology Meets Ecology
→ Heats water only when needed, making it environmentally sound and cost efficient.
→ The ideal solution for people who need both a space heating application and a domestic hot water heater.
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Benefits of Hydronic Heating
→ Clean and comfortable: no air movement means low likelihood for creating dust or excessively dry air.
→ Silent: silent heating, with no blowers needed for forced circulation.
→ Comfort: makes people feel warm and comfortable by keeping the floor warm and indoor air fresh.
→ Coverage: radiant heat from the floor to the ceiling.
→ Economical: radiant heat from the floor can send warmth throughout the house even hours after turning off your heater.
Features
Ultra Condensing Efficiency
→ Navien's Condensing Technology allows high efficiency heating
→ Significant energy savings over traditional water heaters
Dual Stainless Steel Heat Exchangers
→ Longer life expectancy than copper heat exchangers. More resistant to corrosion
→ Less mineral scaling and deposits
Low NOx Emissions
→ New metal fiber burner delivers a consistent gas/air mixture
→ Less greenhouse gas emissions and acid rain
→ SCAQMD 1146.2 compliant
2" PVC, CPVC, Polypropylene Venting
→ 2" vent allows you to install a flue through an existing vent
→ 3" vent can be used up to 150' on standard 2" x 3" adapters
Uses Existing 1/2" Gas Line
→ Dual venturi fan and negative pressure gas valve for better adaptability with low gas pressure
→ Installation in 1/2" gas lines up to 24 feet
Field Convertible
→ Allows easy conversion from/to natural gas and liquid propane
Automatic Water Filling System
→ Automatically fills the space heating pipes with water when the unit senses water shortage.
Powerful Anti-Freeze Feature
→ Built-in Control System keeps the unit's plumbing frost free in winter.
Front Panel Command Center
• Easy setup
• Self-diagnostics
• User friendly interface
• Convertible display from °F to °C
• Cascade operation status display
• Temperature and water flow rate indicator
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Specifications
Important: Navien water heaters are shipped ready for natural gas. Consult the Gas Conversion Guide for use with liquid propane.
NCB-180 | NCB-210 | NCB-240 | |
Space Heating Energy Input | 14,000-80,000 BTU/H | 18,000-100,000 BTU/H | 18,000-120,000 BTU/H |
Domestic Hot Water Energy Input | 14,000-150,000 BTU/H | 18,000-180,000 BTU/H | 18,000-199,900 BTU/H |
AFUE (annual fuel utilization efficiency) | 95% | 95% | 95% |
Flow Rate that results in a 77°F (43°C) Temp Rise | 3.4 GPM (12.9 L/m) | 4.0 GPM (15.1 L/m) | 4.5 GPM (17.0 L/m) |
Dimensions | 17"(W) x 28"(H) x 12"(D) | 17"(W) x 28"(H) x 12"(D) | 17"(W) x 28"(H) x 12"(D) |
Weight | 74 lbs (34kg) | 84 lbs (38kg) | 84 lbs (38kg) |
Installation Type | Indoor Wall-Hung | Indoor Wall-Hung | Indoor Wall-Hung |
Venting Type | Forced Draft Direct Vent | Forced Draft Direct Vent | Forced Draft Direct Vent |
Ignition | Electronic Ignition | Electronic Ignition | Electronic Ignition |
Water Pressure (Hydronic/DHW) | 12-30 PSI / 15-150 PSI | 12-30 PSI / 15-150 PSI | 12-30 PSI / 15-150 PSI |
Natural Gas Supply Pressure (from source) | 3.5"-10.5" WC | 3.5"-10.5" WC | 3.5"-10.5" WC |
Propane Gas Supply Pressure (from source) | 8.0"-13.5" WC | 8.0"-13.5" WC | 8.0"-13.5" WC |
Natural Gas Manifold Pressure (min to max) | -0.07" WC to -0.66” WC | -0.05" WC to -0.36" WC | -0.06" WC to -1.2" WC |
Propane Gas Manifold Pressure (min to max) | -0.06" WC to -0.62" WC | -0.1" WC to -0.66" WC | -0.03" WC to -0.98" WC |
Minimum Flow Rate (DHW) | 0.5 GPM (1.9 L/m) | 0.5 GPM (1.9 L/m) | 0.5 GPM (1.9 L/m) |
Heating Supply/Return Connection | 1" NPT | 1" NPT | 1" NPT |
DHW Inlet/Outlet Connection | 3/4" NPT | 3/4" NPT | 3/4" NPT |
Gas Inlet Connection | 3/4" NPT | 3/4" NPT | 3/4" NPT |
Auto Feeder Connection | 1/2" NPT | 1/2" NPT | 1/2" NPT |
Condensate Outlet Connection | 1/2" NPT | 1/2" NPT | 1/2" NPT |
Main Power Supply | 120V AC, 60Hz | 120V AC, 60Hz | 120V AC, 60Hz |
Maximum Power Consumption | 200W (up to 2 amperes) | 200W (up to 2 amperes) | 200W (up to 2 amperes) |
Casing | Cold Rolled Carbon Steel | Cold Rolled Carbon Steel | Cold Rolled Carbon Steel |
Heat Exchangers | Primary/Secondary Heat Exchanger: Stainless Steel DHW Heat Exchanger: Stainless Steel | Primary/Secondary Heat Exchanger: Stainless Steel DHW Heat Exchanger: Stainless Steel | Primary/Secondary Heat Exchanger: Stainless Steel DHW Heat Exchanger: Stainless Steel |
Exhaust Venting | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) |
Intake Venting | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) | 2” or 3" PVC, CPVC, Polypropylene 2” or 3" Special Gas Vent Type BH (Class II, A/B/C) |
Vent Clearances | 0" to Combustibles | 0" to Combustibles | 0" to Combustibles |
Safety Devices | Flame Rod, APS, Gas Valve Operation Detector, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor | Flame Rod, APS, Gas Valve Operation Detector, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor | Flame Rod, APS, Gas Valve Operation Detector, Ignition Operation Detector, Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor33 |
Downloads
Installation and operation manual
FAQ (Frequently Asked Questions)
Q1: I would like to buy this Navien heater to replace another water heater that uses metal vent pipe. I read the manual that describes various PVC products to use for venting. The manual does not state that metal should not be used. Are there any performance issues if I use my metal exhaust vent pipe and not the PVC type pipe?
A1: Yes, the reason for using PVC versus metal is for energy efficiency. Navien recommends using PVC because the NPE and NR heaters are condensing type heaters. Using PVC provides the maximum condensing function. The Navien heaters will run more efficiently with PVC.
Yes, you could use your metal venting instead of PVC; the heater will still work safely. Alternatively, you could install the PVC inside the metal venting, using the metal venting as a chase (like a conduit).
Q2: Does the NCB-180 ship from the factory configured for natural gas or propane?
A2: It comes configured for natural gas with an easy conversion kit to liquid propane included.
Q3: What is the difference between the NCB and the NCB-E series?
A3: The NCB-E series has five differences: It has an added pressure release valve ("PRV") on the top of the unit, an integrated air vent, a Grundfos pump, a quieter fan, and a more appealing, beveled design on the front cover.
Installation Help and Recommendations
We recommend that you have a professional tankless water heater installer review the above recommendations. Improper installation may cause loss of life and/or property. Need an installer? Get 4 FREE Tankless Water Heater Installation Estimates Now. It's Quick and Easy!
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Alternate model number spelling: NCB180