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NHB Condensing Boiler Installation & Operation Manual Model NHB-055 NHB-080 NHB-110 NHB-150 Keep this manual near this boiler for future reference whenever maintenance or service is required. WARNING If the information in these instructions is not followed exactly, a fire or explosion may result, causing property damage, personal injury, or death.
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Requirements for the State of Massachusetts NOTICE BEFORE INSTALLATION This appliance must be installed by a licensed plumber or gas fitter in accordance with the Massachusetts Plumbing and Fuel Gas Code 248 CMR Sections 2.00 and 5.00. IMPORTANT: In the State of Massachusetts (248 CMR 4.00 & 5.00) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall...
Contents 1. About the Boiler 7. Connecting the Power Supply 1.1 Included Items 8. Installation Checklist 1.2 Accessories 1.3 Specifications 1.4 Components 9. Operating the Boiler 1.5 Dimensions 9.1 Turning the Boiler On or Off 1.6 Rating Plate 9.2 Adjusting the Temperature 9.3 Viewing Basic Information 2.
Safety Information The following safety symbols are used in this manual. Read and follow all safety instructions in this manual precisely to avoid DANGER unsafe operating conditions, fire, explosion, property damage, personal injury, or death. DANGER Indicates an imminently hazardous situation which, if not avoided, could result in severe injury or death.
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CAUTION WARNING Do not turn on the boiler unless the water and gas ● supplies are fully opened. Doing so may damage the boiler. Do not use this boiler for anything other than its ● intended purpose, as described in this manual. Do not remove the front cover unless the power to the ●...
Check the box for each of the following items before installing the boiler. Installation & Operation Manual, Quick Installation Manual User’s Information Manual Navien Manifold System Navien Manifold System (for primary zone) (for secondary zone) 2 in Vent Termination Caps (x2)
2. Based on U.S. Department of Energy (DOE) test procedures. 3. The net AHRI water ratings shown are based on a piping and pickup allowance of 1.15. Consult Navien before selecting a boiler for installations having unusual piping and pickup requirements, such as intermittent system operation, extensive piping system, etc.
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General Specifications Item NHB-055 NHB-080 NHB-110 NHB-150 Dimensions 17in (W) x 12in (D) x 24in (H) 17in (W) x 13in (D) x 24in (H) Weight 73 lb (33 kg) 80 lb (36 kg) Installation Type Indoor Wall-Hung Venting Type Forced Draft Direct Vent...
1.4 Components The following diagram shows the key components of the boiler. Component assembly diagrams and particular parts lists are included in the Appendixes. Intake Air Exhaust Air Filter Air Vent Connection Flue Duct LWCO Front Panel Space Heating Supply Power Switch About the Boiler...
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Ignition Transformer Metal Fiber Premix Burner Igniter & Flame Rod Primary Heat Exchanger Mixing Gas Guide Secondary Heat Exchanger Fan & Motor Gas Valve Dual Venturi Gas Connection Condensate Trap Space Heating Return About the Boiler...
Installation procedures at normal manifold pressure. For installation instructions at altitudes higher than 4,500 ft, please contact Navien. *Cet appareil est certifié pour une utilisation à des altitudes de 0 à 4,500 pieds (1,370 m) conformément aux toutes les procédures d’installation à...
Carefully consider the following factors Navien will not be responsible for water damages that occur as a when choosing an installation location: result. For more information about condensate drainage, refer to “3.2 Connecting the Condensate Drain”...
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Adequate Installation Clearances Clean, Debris and Chemical-free Combustion Air Do not install the boiler in areas where dust and debris may ● accumulate or where hair sprays, spray detergents, chlorine, or CAUTION similar chemicals are used. Do not install the boiler in areas where gasoline or other ●...
2.2 Mounting the Boiler to the Wall WARNING Navien NHB boilers come with an upper mounting bracket that is pre-drilled at 16 in (400 mm) on center for easy installation on The boiler is heavy. Always lift the unit with assistance. Be ●...
All systems, old and new, system. Freeze protection for new or existing systems requires must be cleaned to remove flux, grease and carbon residue. Navien specially formulated glycol, which contains inhibitors to prevent recommends cleaning the boiler system with cleaning products the glycol from attacking the metallic system components.
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(oxygen) and other impurities. To avoid the presence of oxygen, ensure all of the air is removed from The Navien NHB boiler comes with an air vent and an adapter the system during commissioning via strategically placed and bushing that must be connected to the air vent connection.
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Internal LWCO Install a backflow preventer valve in the make-up water supply to the unit as required by local codes. The Navien NHB boiler is equipped with a factory-installed, pressure-sensing type low water cutoff (LWCO) device. The Expansion Tank minimum operation pressure for this device is 6 psi by default.
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Method 2 it is installed in a manifold system. in, 30 psi (max.) pressure relief valve on the space heating hot If the installed system does not have a Navien manifold system, water outlet. An ASME approved HV pressure relief valve for space install a pressure relief valve with the air vent.
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Space Heating Supply The following tables list the specifications for the available pumps and Navien's manifold system. If you are not using one of the pumps listed below, you must use a circulator with check valve installed at pump outlet or a pump with an integral check valve.
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PQ Curves NHB-055/080 NHB-110 Q[GPM] Q[GPM] NHB-150 Q[GPM] Installing the System Piping...
(refer to "3.2.1 Condensate Neutralizer Kit" on page 23). The Navien NHB boiler creates condensation when it operates. This condensation has an acidic pH of 3-5. Follow all local codes If you choose this option, the neutralizing agent Note and regulations when disposing of condensate from the boiler.
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Do not connect more than one appliance to the neutralizer. overflow bypass ● If option 'b' (p. 22) is selected as the disposal option, the Navien condensate neutralizer kit is recommended. The condensate from the appliance flows through the neutralizing media and increases the pH of the condensate.
If the pH level is not specified, replace the neutralizing media when the pH is below 6.0. For replacement media, contact your local Navien distributor. Pressure Relief Valve Air Separator 3.3 Filling the System...
Read and follow the guidelines listed below when installing system Sulfate 205 mg/l piping for the Navien NHB boiler: System application drawings are intended to explain the system ● 2. Close the manual and automatic air vents and the boiler drain piping concept only.
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Refer to the "3.1.1 Guidelines for a Space Heating Installation" on page 34 for wiring connections. Air Handler Interface The Navien NHB boiler can control the operation of an air WARNING handler when a thermostat is used in combination with the air handling unit.
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3.5.2 System Application - Zone System with Zone Valves Additional Zone Zone #2 Zone #1 Zone Valve System Pump (Typical) Air Separator Not to exceed 4 pipe Dia or Max. 12" Make-up Water Backflow preventer Pressure reducing valve Expansion Tank Boiler Pump System application drawings are intended to explain the system piping concept only.
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3.5.3 System Application - Zone System with Pumps Additional Zone Zone #2 Zone #1 Air Separator Not to exceed 4 pipe Dia or Max. 12" Make-up Water Backflow preventer Pressure reducing valve Expansion Tank Boiler Pump System application drawings are intended to explain the system piping concept only. Note ●...
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3.5.4 System Application - Air Handler System Air Separator System Pump (Boiler Pump) Make-up Water Backflow preventer Expansion Tank Pressure reducing valve Air Flow Air Handler System application drawings are intended to explain the system piping concept only. Note ● Refer to "3.3 Filling the System"...
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3.5.5 System Application - DHW System with Indirect Tank System Pump Air Separator Make-up Water Backflow preventer Pressure reducing valve Expansion Tank DHW Outlet Anti-scald mixing valve Indirect Tank Boiler Pump DHW Pump DHW Inlet System application drawings are intended to explain the system piping concept only. Note ●...
3.6 Examples of Electrical Connections 3.6.2 Wiring Diagram - External LWCO WARNING Improperly connecting the electrical supplies can result in electrical shock and electrocution. Follow all applicable electrical codes of the local authority having jurisdiction. CN10 CN12 CN24 CN25 CN29 CN30 Connecting the electrical components should be performed only by a licensed professional.
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3.6.3 Wiring Diagram - the Navien SmartZone + When Navien boilers are used with a Navien Smartzone+ zone pump controller, an RS-485 data communication link is established through the Ready-link connection. This allows the controller and the boiler to share operational information and to control the zones more efficiently by minimizing unnecessary pump operation.
3.6.4 Wiring Diagram - Generic Zone System with 3.6.5 Wiring Diagram - Generic Zone System with Zone Valves Circulators <NHB> <NHB> CN10 CN12 CN24 CN25 CN29 CN30 CN10 CN12 CN24 CN25 CN29 CN30 System System AC24V System AC24V System LWCO Supply LWCO Supply...
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Indirect Tank T/T If you are using the navien manifold system, connect the pump wires to the system pump. If you are not using the navien manifold system, connect the pump wires to either the system pump or the boiler pump.
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3.6.8 Wiring Diagram - Optional Supply/Return Temperature Sensors <NHB> CN10 CN12 CN24 CN25 CN29 CN30 System AC24V System LWCO Supply Return Output Temp. Temp. (optional) (optional) Temperature sensor Cable tie Thermal insulation Refer to "6.1 PCB DIP Switches" on page 48 to control the boiler supply or return water temperature using the external Note temperature sensors, and set the DIP switches accordingly.
This boiler cannot be converted from natural gas to propane ● or vice versa without a Navien gas conversion kit. Do not 5. Install full port valves on the gas supply line and boiler. attempt a field conversion of this boiler without a Navien gas 6.
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BTUs. Also, ensure that the flexible line has no crimps or tight bends in it, as this will restrict gas flow. When using rigid pipe, Navien recommends the ● installation of a union on the gas supply line close to the boiler, to facilitate any future maintenance or service.
4.1 Gas Pipe Sizing Tables The following tables are referenced from 2012 National Fuel Gas Code for reference only. Please consult the gas pipe manufacturer for actual pipe capacities. Maximum Natural Gas Delivery Capacity In Cubic Feet (ft ) per Hour (0.60 Specific Gravity; 0.5 in WC Pressure Drop). Contact your gas supplier for BTU/ft ratings.
Maximum Liquefied Propane Delivery Capacity In Thousands of BTU/H (0.5 in WC pressure drop) Length (including fittings) Pipe Size 10 ft 20 ft 30 ft 40 ft 50 ft 60 ft 80 ft 100 ft 125 ft 150 ft 175 ft 200 ft 250 ft (3 m)
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To measure the inlet gas pressure: 9. Remove the front cover by loosening the 4 Phillips head screws securing it to the case. 1. Shut off the manual gas valve on the gas supply line. Opened Closed Gas Valve 10. Loosen the screws indicated in the figure below and connect a manometer to the pressure port.
We recommend regular filter cleaning and maintenance in these Navien also recommends installing a new vent system with this areas. appliance. If reusing an existing vent system, thoroughly inspect For best results, keep the venting system as short and straight as ●...
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Description Canadian Direct Vent Installations US Direct Vent Installations Clearance above grade, veranda, porch, deck, or balcony 12 in (30 cm) 12 in (30 cm) Clearance to window or door that may be opened 36 in (91 cm) 12 in (30 cm) Clearance to permanently closed window Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 ft (61 cm) from...
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Vent Pipe 2" problem, any freezing damage which occurs from back drafting will not be covered by the Navien warranty. If there is any question about the possibility of back drafting in the installation location, use a direct venting system for the boiler.
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Canadian Non-Direct Vent US Non-Direct Vent Description Installations Installations Clearance above grade, veranda, porch, deck, or balcony 12 in (30 cm) 12 in (30 cm) 48 in (120 cm) below or to side Clearance to window or door that may be opened 36 in (91 cm) of opening;...
5.2 Selecting Vent Pipe Materials When PCB DIP switch 2 #8 is set to Off (factory Note ● default), the boiler does not operate without an exhaust thermostat installed. Venting requirements differ in the US and Canada. Consult the following chart or the most recent edition of ANSI Z223.1/NFPA When you set PCB DIP switch 2 #8 to On, ensure ●...
5.4 Terminating the Vent Indoor Boiler Installation Venting Examples The following are some possible indoor venting options: Before installing the boiler, determine what type of vent termination is appropriate for the installation location and 2 in or 3 in Two-pipe Sidewall Venting ●...
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Non-concentric Sidewall Venting – Air is drawn from a different 2 in or 3 in Two-pipe Vertical Venting – Intake and exhaust pipes ● ● location that is at least 12 in (300 mm) away from the exhaust do not have to terminate in the same area. termination.
6. Setting the DIP Switches Dip Switch 2 (8 switch unit) CAUTION The DIP SW 2 on the circuit board configures the temperature control modes, country, and enables or disables the space heating Do not remove the front cover unless the power to the thermostat.
6.2 Front Panel Dip Switches Dip Switch 2 (2 switch unit) The DIP SW 2 on the front panel configures settings for the type of Dip Switch 1 (10 switch unit) gas. Before changing the settings, lift the rubber cover to access the The DIP SW 1 on the front panel configures the temperature unit front panel DIP switches.
Do not connect the boiler to a 220-240V AC power supply. Doing ● so will damage the boiler and void the warranty. All the Navien NHB boilers are supplied with a factory-installed, ● 3-pronged (grounded) plug. The boiler’s current rating is 5 A and can be plugged into any grounded electrical outlet adjacent to the boiler.
To troubleshoot any operational problems refer to “Troubleshooting” in the Owner’s Manual. If you have additional questions or need assistance with installation, contact Technical Support at 1-800-519-8794 or 1-949-420-0420, or refer to the technical support section of Navien’s website (www.navien.com). Installing the boiler...
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Connecting a Pressure Relief Valve Have you installed an approved pressure relief valve on the boiler? Does the rating of the pressure relief valve match or exceed the maximum BTU rating of the boiler? Is the pressure relief valve in on the space heating outlet? Have you installed the pressure relief valve on the space heating supply pipe near the boiler? Have you installed a discharge drain tube from the pressure relief valve to within 6-12 in (150-300 mm) of the floor? Connecting the Condensate Drain...
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PCB DIP switch setting (DIP SW 2, set of 8) Is switch #1 set correctly for Return Water Control (ON) or Supply Water Control (OFF)? If continuous boiler operation is required, is switch #7 in the up (ON) position? If high temperature venting has been installed (CPVC or polypropylene), is switch #8 in the up (ON) position? Front Panel DIP switch setting (DIP SW 1, set of 10) Is switch #2 set correctly for Celsius (ON) or Fahrenheit (OFF)? Is switch #4 and #5 are set correctly for the installation altitude?
9. Operating the Boiler 9.1 Turning the Boiler On or Off 2. Press the + (Up) or – (Down) buttons until the desired temperature appears on the display. To turn the boiler on or off, press the Power button for 0.3 seconds. MODE MODE You can adjust the temperature while the display is flashing.
9.2.2 Adjusting the DHW Indirect Supply 9.3 Viewing Basic Information Temperature To view information about the boiler, press the Mode button three To adjust the water temperature: times. “INFO” will appear on the display. 1. Press the Mode button twice. The DHW mode icon turns on. 2.
Display Description Display Description Space heating return water Space heating water pressure in PSI temperature (°F) DHW priority time Not Available System supply water temperature (°F) (with optional temperature Not Available sensor) System return water temperature (°F) (with optional temperature Not Available sensor) Outdoor air temperature (°F)
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Display Description Display Description System supply water temperature Blower fan motor target RPM (x 10) (°F) (with optional temperture sensor) System return water temperature Blower fan motor current RPM (x 10) (°F) (with optional temperture sensor) APS target voltage DHW priority time in minutes Current exhaust gas temperature2 APS current voltage (°F)
9.5 Setting the Operation Mode Display Description 1. On the Front Panel, press and hold the Diagnostics Button for over 5 seconds until “1.PAR” is displayed. DHW pump status Overheating sensing (HTL) status MODE Dual venturi status Low water cut-off (LWCO) status 2.
9.6 Setting the Parameters If you enter an incorrect password 10 times or make Note ● no inputs 5 minutes, the boiler will return to Normal mode. You can modify parameter settings for boiler operations, such as the space heating and DHW temperature ranges, in different To return to the previous mode, press the Reset ●...
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Setting the Heat Load for the Outdoor Reset Control Mode Setting the Lowest Outdoor Temperature Display Description Display Description Outdoor Reset heat load types 1: Finned tube baseboard Lowest outdoor temperature (°F) 2: FAN coil 3: Cast iron baseboard 4: Low mass radiant 5: High mass radiant 6: Radiator Lowest outdoor temperature not...
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Setting the Pump Freeze Protection Temperature Setting the Boost Interval Time Display Description Display Description Pump freeze protection temperature Boost interval time (min) (°F) This menu is used to configure the circulation pump freeze The boost interval time may be set to prevent interruption in protection temperature.
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Setting the Pump Overrun Time Setting the Burner-On Temperature Differential Display Description Display Description Pump overrun time (min) Burner-on temperature (°F) The pump overrun time is the duration the circulation pump During space heating, the boiler turns on the burner when continues to run between the space heating supply or return the space heating supply temperature is below the burner-on temperature reaching the set point and the burner turning off.
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Setting the Supply Absolute MIN Temperature Setting the Return Absolute MIN Temperature Display Description Display Description Supply absolute Min set point (°F) Return absolute MIN set point (°F) This menu can be used to change the minimum supply This menu can be used to change the minimum return temperature range in Supply Control mode.
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(On) T-T Zone Controller Connection (Off) Use system pump (Yes) Use this menu to operate the boiler with a Navien SmartZone+ Use this menu to set system pump operation for DHW mode. controller connected via a Ready-Link cable. Default: Off ●...
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Low Burning Time Setting the Space Heating Min Heat Capacity Display Description Display Description Low burning time during initial DHW Min heat capacity (%) heating Default: 1 min ● This menu is used to configure the desired DHW minimum capacity. When the boiler operates in Normal mode, the minimum Range: 1–20 min ●...
9.7 Resetting the Boiler Setting a New Password If an error message appears, reset the boiler to resolve the Display Description problem. To reset the boiler, press the Reset button. Change password This menu may be used to set a new password to access the MODE parameter setting menu.
WARNING This conversion kit must be installed by a qualified service agency* in accordance with Navien’s instructions and all applicable codes and requirements of the authority having jurisdiction. The information in these instructions must be followed to minimize the risk of fire or explosion or to prevent property damage, personal injury or death.
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7. Remove the PCB assembly. 10. Once the gas inlet pipe is detached from the gas valve, find location B - the connection above the gas valve where it is attached to the fan motor assembly. Carefully remove the four screws by hand using a Phillips screwdriver and pull the gas valve away from the fan assembly to access the gas orifice.
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Failure to comply will Navien NHB boilers are shipped ready to fire natural gas cause a gas leak, resulting in severe personal injury or death. ONLY.
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Fuel The set screw is located behind the screw-on Note cover. This must be removed first. NHB-055 10.2 10.8 d. Activate multiple zones and set the boiler to operate at 2-stage D. MAX mode (refer to “9.5 Setting the Operation Mode”...
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Offset NAC-N1 -0.04 in ±0.01 in The set screw is located behind the screw-on cover. Note NHB-055 This must be removed first. NAC-L1 -0.03 in ±0.01 in d. At high fire, do not check the offset value and never adjust NAC-N2 -0.04 in ±0.01 in...
Make sure wiring connections are secure before closing the cap. ● The sensor is a water resistant device. ● Any damage to the device may require the replacement of the ● entire component. Navien Outdoor Temperature Sensor Kit Appendixes...
10.6 Outdoor Reset Control Outdoor Temperature Sensor Installation Guidelines The Outdoor Reset Control feature may be used to enhance energy Supply Set Point Return Set Point efficiency while maintaining optimal heating performance. With Heat Load Range Range the Outdoor Reset Control, the space heating temperature setting automatically changes according to the outdoor temperature and Finned Tube 120-180°F...
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NHB Condensing Boiler Installation & Operation Manual Getting Service If your boiler requires service, you have several options for getting service: Contact Technical Support at 1-800-519-8794 or on the website: www.navien.com. ● For warranty service, always contact Technical Support first. ●...
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