Navien NFB-175H Installation Manual
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Navien NFB-175H Installation Manual

Condensing boilers
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Installation Manual
NFB-H Condensing Boilers
Model
NFB-175H
NFB-200H
WARNING
If the information in these instructions is not followed exactly, a fire or explosion may result,
causing property damage, personal injury, or death.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or
any other appliance.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
●
Do not touch any electrical switch; do not use any phone in your building.
●
Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instructions.
●
If you cannot reach your gas supplier, call the fire department.
●
Installation and service must be performed by a qualified installer, service agency or the gas
supplier.
The installation must conform with local codes or, in the absence of local codes, the
National Fuel Gas Code, ANSI Z223.1/NFPA 54 and/or CSA B149.1, Natural Gas and Propane
Installation Code.
Keep this manual near this boiler
for future reference whenever
maintenance or service is required.

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Summary of Contents for Navien NFB-175H

  • Page 1 Installation Manual NFB-H Condensing Boilers Model NFB-175H NFB-200H 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.
  • Page 2 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 4.00 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...

  • Page 3: Table Of Contents

    9. Installing a Common Vent System 77 1.4 Components 1.5 Dimensions 9.1 About the Common Vent System 1.6 Rating Plate 9.2 Navien Common Vent Collar Kit (Back- draft Damper) 2. Installing the Boiler 9.3 Starting the Common Vent System 9.4 Connecting and Terminating the Vent 2.1 Removing the Wood Pallet from the boiler 13...
  • Page 4 Safety Information The following safety symbols are used in this manual. Read and follow all safety instructions in DANGER this manual precisely to avoid 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.
  • Page 5 California law requires the following Prop 65 warning to be provided: WARNING WARNING Cancer and Reproductive Harm - www.P65Warnings.ca.gov. CAUTION Do not turn on the boiler unless the water ● and gas supplies are fully opened. Do not store or use gasoline or other ●...

  • Page 6: About The Boiler

    1. About the Boiler 1.1 Included Items 1.2 Accessories When you open the box, you will find the following The following optional accessories are available for items with the boiler. Check the box for each of the the boiler. following items before installing the boiler. Installation &...

  • Page 7: Specifications

    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.
  • Page 8 General Specifications Item NFB-175H NFB-200H Dimensions 17.3 in (W) x 17.3 in (D) x 27.6 in (H) Boiler weight 121 lb (55 kg) Boiler weight with water 148 lb (67 kg) Installation Type Indoor Wall-Hung Venting Type Forced Draft Direct Vent...

  • Page 9: Components

    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 Duct Vent Installation Air Vent Connection Detector Mixing Chamber Igniter Fan & Motor Assembly Flame Rod Dual Venturi...
  • Page 10 Air Intake Filter Mixing Chamber Fan & Motor Assembly Dual Venturi Igniter Flame Rod Igniter Transformer Gas Valve Fire-Tube Type Heat Exchanger Air Intake Pipe Gas Pipe ASME Name Plate Front Panel Terminal Block 24 V Power Power Switch Transformer Heating Return Heating Supply Gas Inlet...

  • Page 11: Dimensions

    1.5 Dimensions The following diagrams show the dimensions of the boiler and the table lists the supply connections. Supply Connections Description Diameter Air Intake 2 in Exhaust Gas Vent 2 in Air Vent Connection Heating Supply Heating Return Gas Connection Condensate Outlet Overhead View Supply Connections...

  • Page 12: Rating Plate

    1.6 Rating Plate The Navien NFB-H boilers come from the factory configured for use with Natural Gas (NG). Before starting the installation, check the rating plate located on the side of the boiler to ensure that the boiler matches the gas type, gas pressure, water pressure, and electrical supply available in the installation location.

  • Page 13: Installing The Boiler

    2. Installing the Boiler 2.1 Removing the Wood Pallet 2. Remove the wood pallet, the upper container, and the lower pad. from the boiler After you open the box, remove the wood pallet and the pallet brackets and then install the boiler. Upper Container CAUTION...

  • Page 14: Choosing An Installation Location

    2.2 Choosing an Installation 4. Remove the two pallet brackets. Location When choosing an installation location, you must ensure that the location provides adequate clearance for the boiler, adequate venting and drainage options, and sufficient access to gas, water, and electrical supplies. Carefully consider the following factors when choosing an installation location: Compliance Requirements...
  • Page 15 Do not install the boiler on carpeting. boiler in a location without a drain will void the warranty and Navien will not be responsible for water damages that occur as a result. For more Install the boiler in an area that allows for service information about condensate drainage, refer to “3.2...

  • Page 16: Mounting The Boiler To The Wall

    2.3 Mounting the Boiler to the Wall Navien NFB-H boilers come with an upper mounting bracket that is pre-drilled at 16 in (400 mm) on center for easy installation on standard wall studs. If the strength of the wall is insufficient or if the framing is non-standard or uneven, reinforce the area before installing the boiler.
  • Page 17 WARNING The boiler is heavy. Always lift the unit with ● assistance. Be careful not to drop the boiler while lifting or handling it to avoid bodily injury or damage to the unit. Do not rest the boiler on the bottom end ●...

  • Page 18: Installing The System Piping

    See System page 24 for additional information regarding the use of glycol. The fire-tube type heat exchanger of the Navien NFB-H boiler is designed to attain the highest level of heat transfer in a compact design. To accomplish WARNING this, the heated gas flows through a series of small- diameter tubes, maximizing the heat transfer area.
  • Page 19 Air Vent boiler outlet. To obtain the minimum system design pressure, follow the piping diagrams The Navien NFB-H boiler comes with an air vent and illustrated in this section. an adapter bushing that must be connected to the The Navien NFB-H boiler’s space heating system air vent connection.
  • Page 20 External LWCO Connect an air separator to the expansion tank ● only if the air separator is located on the suction If local codes require a separate LWCO device, side of the system pump. install one separately. Combining the LWCO with Install the make-up water connection at the same ●...
  • Page 21 If the installed system does not have a Navien manifold system, install a pressure relief valve with the air vent. The illustration below shows an example CAUTION of a pressure relief valve installed with the air vent.
  • Page 22 Space Heating Return 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.
  • Page 23 PQ Curve NFB-175H/200H H[ft] Q[GPM] Q [GPM] 10.6 13.2 15.9 18.5 21.1 23.8 26.4 H [ft] 11.5 Maximum and Minimum Flow Rates through the Boiler Model Minimum Pipe Diameter Maximum Flow (GPM) Minimum Flow (GPM) NFB-175H " 23.1 NFB-200H "...
  • Page 24 Head Flow Rate Head Flow Rate Head (GPM) (Ft) (GPM) (Ft) (GPM) (Ft) NFB-175H NFB-200H 20°F ΔT @ 50% glycol 25°F ΔT @ 50% glycol 35°F ΔT @ 50% glycol Model Flow Rate Head Flow Rate Head Flow Rate Head...

  • Page 25: Connecting The Condensate Drain

    2. Insert the condensate trap to the drain adapter at the bottom of the boiler. Drain The Navien NFB-H boiler creates condensation when it operates. This condensation has an acidic pH of 3-5. Follow all local codes and regulations when disposing of condensate from the boiler. We recommend draining the condensate into a suitable external drain.
  • Page 26 Before connecting the condensate drain, choose To connect the condensate drain: one of the following disposal options: 1. Connect a drain line to the in fitting at the bottom of the boiler. Use only corrosion-resistant material for the drain line, such as PVC or CPVC. Do not reduce the size of this fitting or the drain line to less than NPT 1/2”...
  • Page 27 Do not connect more than one appliance to ● the neutralizer. If option ‘b’ (p. 25) is selected as the disposal option, the Navien condensate neutralizer kit is recommended. The condensate from the appliance Optional overflow bypass flows through the neutralizing media and increases the pH of the condensate.

  • Page 28: Filling The System

    If the pH Screw level is not specified, replace the neutralizing media when the pH is below 6.0. For replacement media, contact your local Navien distributor. Ensure that the vent cap is re-installed Note and the vent screws on the system and boiler pumps are properly tightened before testing or operating the system.

  • Page 29: Testing The Water System

    3.3.1 Make-up Water Connection 1. Fill the system only after ensuring that the water chemistry meets the requirements. An external make-up water connection is required. The illustration below shows an example of an Contaminant Maximum Allowable Level external water supply connected to the system piping.

  • Page 30: Considerations For System Applications

    Read and follow the guidelines listed below when up water pressure. installing system piping for the Navien NFB-H boiler: System application drawings are intended to Ensure the expansion tank cannot become isolated ●...
  • Page 31 Air Handler Interface Refer to the “3.6.9 Wiring Diagram - Air Handler” on page 45 for wiring connections. The Navien NFB-H boiler can control the operation of an air handler when a thermostat is used in WARNING combination with the air handling unit. The Air...
  • Page 32 3.5.2 System Application - Zone System with Zone Valves (Primary/Secondary Piping) Additional Zone Zone #2 Zone #1 Zone Valve System Pump (Typical) Air Separator Return filter 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.
  • Page 33 3.5.3 System Application - Zone System with Pumps (Primary/Secondary Piping) Additional Zone Zone #2 Zone #1 Air Separator Return filter 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.
  • Page 34 3.5.4 System Application - Air Handler System System Pump Air Separator (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 ● Install a filter in the system return to remove foreign objects from the system.
  • Page 35 3.5.5 System Application - DHW System with Indirect Tank (Primary/Secondary Piping) System Pump Air Separator Return filter Make-up Water Backflow preventer Pressure reducing valve Expansion Tank Anti-scald mixing valve Indirect Tank Boiler Pump DHW Pump DHW Inlet DHW Outlet System application drawings are intended to explain the system piping concept only. Note ●...

  • Page 36: Examples Of Electrical Connections

    3.6 Examples of Electrical Connections WARNING Improperly connecting the electrical supplies can result in electrical shock and electrocution. Follow all applicable electrical codes of the local authority having jurisdiction. Connecting the electrical components should be performed only by a licensed professional. CAUTION Label all wires before disconnecting them 3.6.2 Wiring Diagram - External LWCO...
  • Page 37 3.6.3 Wiring Diagram - Zone Pump System The NFB-H Boilers can operate a heating system with up to 3 zones. The following is the wiring diagram for a zone pump system with 3 zones. Without 24VAC connections LWCO AC24VL LWCO AC24VN AC24VL AC24VN...
  • Page 38 With 24VAC connections LWCO AC24VL LWCO AC24VN AC24VL AC24VN 24 VAC N Thermostat Input 24 VAC L Thermostat 1 Boiler pump (max. 2.5 A) 24 VAC N LWCO AC24VL AC24VN Thermostat Input 24 VAC L Thermostat 2 SUPPLY RETURN OUTDOOR DHW TANK Zone pump 1 (max.
  • Page 39 3.6.4 Wiring Diagram - Zone Pump System with DHW Tank The NFB-H Boilers can operate a heating system with up to 2 zones and 1 DHW Tank. The following is the wiring diagram for a zone pump system with 2 zones and 1 DHW Tank. Without 24VAC connections LWCO AC24VL...
  • Page 40 With 24VAC connections LWCO AC24VL LWCO AC24VN AC24VL AC24VN DHW Aquastat (priority) 24 VAC N Thermostat Input 24 VAC L Thermostat 1 Boiler pump (max. 2.5 A) 24 VAC N LWCO AC24VL Thermostat Input AC24VN 24 VAC L Thermostat 2 DHW pump SUPPLY RETURN...
  • Page 41 3.6.5 Wiring Diagram - Zone Valve System The NFB-H Boilers can operate a heating system with up to 3 zones. The following is the wiring diagram for a zone valve system with 3 zones. Without 24VAC connections Zone valve 1 (max.
  • Page 42 With 24VAC connections Zone valve 1 (max. 1A) Zone valve 2 (max. 1A) Zone valve 3 (max. 1A) LWCO LWCO AC24VL LWCO AC24VL AC24VN LWCO AC24VL Boiler pump AC24VN AC24VN AC24VL (max. 2.5 A) AC24VN LWCO AC24VL AC24VN SUPPLY RETURN OUTDOOR DHW TANK DHW pump...
  • Page 43 3.6.6 Wiring Diagram - the Navien SmartZone + The Navien Smart Zone + controller may be used with the NFB-H Boilers to operate a heating system with more than 3 zones. 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.
  • Page 44 3.6.7 Wiring Diagram - Generic Zone 3.6.8 Wiring Diagram - Generic Zone System with Zone Valves System with Circulators <NFB-H> <NFB-H> AC24VN AC24VN LWCO LWCO AC24VL AC24VL AC24VN AC24VN SUPPLY RETURN OUTDOOR DHW TANK SUPPLY RETURN OUTDOOR DHW TANK SUPPLY RETURN OUTDOOR DHW TANK...
  • Page 45 LWCO AC24VL AC24VN SUPPLY RETURN OUTDOOR DHW TANK If you are using the Navien manifold system, SUPPLY RETURN OUTDOOR DHW TANK 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.
  • Page 46 When connecting the DHW Tank Sensor The Navien Universal Temperature sensor can be used as a DHW Tank Sensor. When installing the Universal Temperature sensor to the boiler, follow these guidelines: This sensor is compatible for use with aquastat immersion wells. Attach an aquastat immersion well to the ●...
  • Page 47 3.6.11 Wiring Diagram - Optional Supply/Return Temperature Sensors <NFB-H> SUPPLY RETURN OUTDOOR DHW TANK Temperature sensor Cable tie Thermal insulation To control the boiler supply or return water temperature using the external temperature sensors, Note configure the system accordingly. On the front panel, press the Menu button ( ) to enter the setting menu, and then select 2.

  • Page 48: Connecting The Gas Supply

    This boiler cannot be converted from natural ● Gas Supply Line gas to propane or vice versa without a Navien gas conversion kit. Do not attempt a field conversion of this boiler without a Navien gas conversion kit. Doing so will result in dangerous operating conditions and will void the warranty.
  • Page 49 BTUs. Also, ensure that the flexible line has no crimps or tight Gas Shut off bends in it, as this will restrict gas flow. Valve When using rigid pipe, Navien ● Union recommends the installation of a union on the gas supply line close to the boiler, to facilitate any future maintenance or service.
  • Page 50 Single Regulator System Typical LP Gas piping examples: 2 Stage System with Multiple Gas Regulator (12” WC) Regulators(Recommended) Full size Pipe Gas Pipe Gas Regulator (2 Stage) High Pressure Low Pressure Regulator Gas Tank Full size Regulator (to home or building) Gas Pipe Gas Tank Full size...

  • Page 51: Gas Pipe Sizing Tables

    4.1 Gas Pipe Sizing Tables The following tables are referenced from the 2012 National Fuel Gas Code and are 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;...

  • Page 52: Measuring The Inlet Gas Pressure

    Maximum Liquefied Propane Delivery Capacity In Thousands of BTU/H (0.5 in WC pressure drop) Length (including fittings) Pipe 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 Size...
  • Page 53 To measure the inlet gas pressure: 8. Unfasten the 4 latches (2 at the top and 2 at the bottom) to remove the front cover and gain 1. Shut off the manual gas valve on the gas supply access to the internal components. line.

  • Page 54: Venting For Combustion Air

    5. Venting for Combustion Air Additional Guidelines for Combustion Corrosive Contaminants Muriatic acid/hydrochloric acid Combustion air piping to the outside is ● Refrigerant leaks recommended. (Direct Venting) Chlorine-type bleaches, detergents, and cleaning The boiler may be installed with a single pipe ●...

  • Page 55: Venting The Boiler

    5.1 Venting the Boiler Do not install the boiler in areas with ● contaminated air (containing a high level of dust, sawdust, sand, flour, aerosols, or any other such airborne contaminants), as contaminants can DANGER cause operational problems. The warranty does not cover damage caused by contaminants in the This appliance is certified as a “Category IV”...
  • Page 56 1. Measure 3.0” inches from the end of the vent CAUTION pipe, then draw a mark at that distance. Do not start the vent run with a street elbow at the vent collar. Using an elbow directly at the Mark 3.0” from collar will not allow for a tight seal between the the end of the pipe appliances and vent pipe.

  • Page 57: About The Vent Installation Detector

    Purpose DANGER The VID’s purpose is to guide the installer to fully insert the vent pipe to a depth of at least 3.0 inches If the connections leak, harmful flue gas may or 76 mm, into the collar. If the vent pipe is not cause personal injury or death.
  • Page 58 WARNING WARNING The failure to properly install the vent pipe ● into the boiler collar or using incorrectly The vent sized vent pipe materials in strict compliance installation with installation instructions may cause the detector vent pipe to separate from the boiler which will result in excessive carbon monoxide emissions extremely...

  • Page 59: Selecting A Vent Type

    5.3 Selecting a Vent Type All Navien boilers are Category IV appliances and prepared at the factory to be direct vented (sealed combustion). Navien recommends direct air vent installations whenever possible to avoid back drafting cold air through the boiler unit. If you cannot use a direct vent, ensure that an ample supply of make-up air is available in the installation location.
  • Page 60 Canadian Direct US Direct Vent Description Vent Installations Installations Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 ft (61 cm) from the center line of the terminal Clearance to unventilated soffit Clearance to outside corner Clearance to inside corner 3 ft (91 cm) within a Clearance to each side of center line extended above...
  • Page 61 50 in which occurs from back drafting will not be covered 199 in 10 in (W) x by the Navien warranty. If there is any question NFB- 199,900 5 in (H) or about the possibility of back drafting in the...
  • Page 62 Canadian Non-Direct US Non-Direct Vent Description Vent Installations Installations Clearance above grade, veranda, porch, deck, or 12 in (30 cm) 12 in (30 cm) balcony 48 in (120 cm) below or Clearance to window or door that may be opened 36 in (91 cm) to side of opening;...

  • Page 63: Selecting Vent Pipe Materials

    5.4 Selecting Vent Pipe Materials When you set PCB DIP SW2 (Set of 8 Note Switches) #8 to On, ensure that CPVC, polypropylene or stainless steel piping Venting requirements differ in the US and Canada. is used for exhaust venting. Consult the following chart or the most recent edition of ANSI Z223.1/NFPA 54 or CAN/CGA B149.1, as well as all applicable local codes and regulations...

  • Page 64: Measuring Vent Length

    5.5 Measuring Vent Length Hart & Cooley Polyflue™ SW (Rigid) (Certified to ULCS636) 2PF-xx (2”) or 3PF-xx (3”) The maximum vent length when using 2 in exhaust Z-Flex Z-DENS SW (Rigid) (Certified to UL1738 and ducts is 65 ft (20 m). The maximum vent length ULCS636) when using 3 in vent ducts is 150 ft (45 m).

  • Page 65: Terminating The Vent

    5.6 Terminating the Vent Centrotherm Innoflue® (Certified to UL1738 and ULCS636) ISELL0287 or ISELL0387 (2” or 3” 87° Elbow) Before installing the boiler, determine what type of ISELL0245 or ISELL0345 (2” or 3” 45° Elbow) vent termination is appropriate for the installation IST02 or IST03 (2”...
  • Page 66 Indoor Boiler Installation Venting Two-pipe Vertical Venting - Intake and exhaust ● pipes do not have to terminate in the same area. Examples Exhaust Gas 36” (900 mm) min. The following are some possible indoor venting options: 12” (300 mm) min. Two-Pipe Sidewall Venting ●...
  • Page 67 Indoor Boiler Installation Venting Concentric Sidewall Venting ● Examples (continued) Combustion Air intake Low Profile Two-Pipe Sidewall Venting* Combustion ● Air intake Exhaust Exhaust Exhaust Intake Air (from (from outdoors) 1" (25 mm) min. appliance) Maintain 12" (300 mm) min. clearance above highest anticipated snow level or grade, whichever is greater Concentric Vertical Venting ●...
  • Page 68 Flexible Vent Systems (Polypropylene) ● Only VERTICAL installations are Note ● allowed. Horizontal terminations are prohibited. The use of proper adapters and ● supports are required to fully complete the installation. The following table lists the flexible vent models that are approved for use with this appliance in addition to the maximum allowable vent lengths for the desired vent system.

  • Page 69: Setting The Dip Switches

    The DIP SW1 (Set of 6 Switches) on the circuit board configures the operation status and model settings. Switch Function Setting Normal Operation 1-OFF, 2-OFF 2-stage MAX 1-ON, 2-OFF 1 & 2 Operation Status 1-stage MIN 1-OFF, 2-ON 1-stage MAX 1-ON, 2-ON NFB-200H 5-OFF, 6-OFF 5 & 6 Model Setting NFB-175H 5-ON, 6-OFF Setting the DIP Switches...

  • Page 70: Dip Switch 2 (Set Of 8 Switches)

    6.2 Dip Switch 2 (Set of 8 Switches) The DIP SW2 (Set of 8 Switches) on the circuit board configures the gas type, altitude, temperature control modes, country, and enables or disables the space heating thermostat. Switch Function Setting Comment Natural Gas 1-OFF Gas Type...

  • Page 71: Connecting The Power Supply

    ● power supply. Doing so will damage the boiler CAUTION and void the warranty. All the Navien NFB-H boilers are supplied with a ● Label all wires before disconnecting them factory-installed, 3-pronged (grounded) plug. The when you work on the controls. Wiring errors boiler’s current rating is 12 A and can be plugged...

  • Page 72: Installing A Cascade System

    Use pumps with integral check valves or install check valves at the pump outlets. ● Navien system supply (Included box)/return (Accessory) Temperature sensor must be installed for ● cascade system operation. Adjust the settings at the main unit as the cascade system uses only the main unit settings.
  • Page 73 System Application #1- Cascade System with Closely Spaced Tees ● Main Sub1 Sub2 Supply Air separator Cold water Backflow preventer Expansion tank Temperature 12” (30 cm) sensors (required) maximum Return Connect the “SH Demand (SH T/T or Zone controller)” to the main unit. Note ●...
  • Page 74 System Application #3- Cascade System with DHW Indirect Tank (for High DHW Demand) ● System Air separator pump Supply Cold water Backflow preventer Main Sub1 Sub2 Expansion tank Indirect tank Aquastat Temperature 12” (30 cm) sensors (required) maximum Cold water Return In this configuration, the full capacity of all boilers will be prioritized to the DHW demand.
  • Page 75 System Application #5- Cascade System with DHW Indirect Tank (for Low DHW Demand) ● Supply Main Sub1 Sub2 Indirect Air separator tank Cold water Backflow preventer Expansion tank Aquastat Temperature sensors (required) Return Cold water In this configuration, space heating and DHW can operate simultaneously. Note ●...

  • Page 76: Connecting The Communication Cables

    When plumbing a cascade system, consider the following pipe diameters and flow rates. Note that Up to 16 boilers can be connected with Navien flow rates above 4 ft/s may cause pipe erosion Ready-Link communication cables. Select one of the or velocity noise.

  • Page 77: Installing A Common Vent System

    9.1.1 Guidelines for a Common Vent System System The Navien Common Vent System* provides an easy way to install the vent system for up to 8 Navien CAUTION NFB-H boiler units. By sharing the main intake and exhaust vent pipes, effective system venting is To ensure the correct operation of the ●...
  • Page 78 Adequate Installation Clearances To avoid moisture and frost build-up and to ● maintain clearances to openings on adjacent homes, 45° elbows, 90° elbows, or tees may be attached to the end of the termination vent pipe CAUTION to direct the exhaust plumes away from buildings, as long as the total allowable vent lengths, Do not install the boiler on carpeting.
  • Page 79 Clean, Debris and Chemical-free Cutting and Assembling Common Vent Combustion Air System Components Do not install the boiler in areas where dust and ● Standard tools are suitable for the cutting and debris may accumulate or where hair sprays, assembly of common vent system components. spray detergents, chlorine, or similar chemicals Follow the guidelines listed below when working are used.
  • Page 80 Vent Pipe Pitch and Supports 3. Hold the pipe and pipe fitting together for about 15 seconds until the cement sets. For horizontal runs, slope the horizontal section Use approved solvent type cement Note ● upward toward the vent termination at a rate of ”...
  • Page 81 (H): Total length (L) = W The following illustration depicts an example of a + H. common vent system installed for a cascade system of 8 Navien NFB-H boiler units. Exhaust End cap Intake Siphon loop...

  • Page 82: Navien Common Vent Collar Kit (Back-Draft Damper)

    9.2 Navien Common Vent Collar Specifications Kit (Back-draft Damper) The Navien Common Vent Collar Kit includes a backdraft damper preventing the flue gases and cold outside air from entering the water heater when the combustion fan is off. The kit includes the 5.9”...

  • Page 83: Starting The Common Vent System

    Refer to “9.8 Maintenance” for detailed inspection 3. Connect the Common Vent Collar Kit to the procedures of the Navien Common Vent Collar Kit exhaust duct of the boiler unit. (Back-draft Damper). When using a common vent in a Note...
  • Page 84 5. Remove the front cover of the boiler, and 1. Measure 1- ” from the end of the vent pipe, connect the provided VID jumper wire as shown then draw a mark at that distance. below. You must connect it to the wire with the “VID”...
  • Page 85 2. Assemble the wye joint or wye assembly to the vent pipe. Apply solvent cement to the mating CAUTION surfaces. Do not start the vent run with a street elbow at the vent collar. Using a street elbow directly at the collar will not allow for a tight seal between the appliance and vent pipe.

  • Page 86: Connecting And Terminating The Vent Pipe

    9.4 Connecting and Terminating the Vent Pipe Refer to the following example to install the common vent system. The installation area should be measured to ensure that sufficient space is available to install the boiler units and the common vent system. Ensure that the common vent system is installed near the boiler units while satisfying all clearance requirements that are specified in this manual as well as the Installation Manuals supplied with the boiler units.

  • Page 87: Setting Up The Common Vent System

    9.5 Setting up the Common Vent 9.6 Common Vent Termination System Clearances Refer to the following figures when setting the common vent type. 9.6.1 Direct Vent Application – Vertical Installation To view and configure the cascade settings, press the Back button ( ) and the Menu button ( simultaneously for 3 seconds, and then select 36"...
  • Page 88 9.6.3 Direct Vent Application – Horizontal Installation i n . m ) m 0 0 m 1 2 " ( 3 Exhaust Maximum Exhaust Gas length 20’ (6 m) Minimum length 36” Intake Intake Air (91 cm) In cases where a 12” horizontal clearance is not The illustration is intended for Note ●...

  • Page 89: Installing A Condensate Drain

    9.7 Installing a Condensate Drain To install a condensate drain to the common vent system: Refer to the following examples to install a condensate 1. Form a loop with a drain hose and fix it with a drain hose (field supplied) to the common vent system. tie.

  • Page 90: Maintenance

    9.8 Maintenance 3. Reinstall the gasket and maintenance port cover, and then fix them with a set screw. Periodically check the damper condition inside the Common Vent Collar Kit through the maintenance port to ensure optimal performance of the system. Follow the instructions to check the damper condition and replace the Common Vent Collar Kit if necessary.

  • Page 91: Installation Checklist

    “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.navieninc.com). Installing the boiler...
  • Page 92 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?
  • Page 93 Connecting the Power Supply Is the supplied voltage 110-120V AC? Is the boiler plugged into a properly grounded outlet? If you have made a direct power supply connection, have you installed a power switch to facilitate end-user maintenance? Have you checked the polarity of the electrical connection? PCB DIP switch setting (DIP SW2 (Set of 8 Switches)) Gas type: Is switch #1 set correctly for LP (ON) or NG (OFF)? If continuous boiler operation is required, is switch #7 in the up (ON) position?

  • Page 94: Operating The Boiler

    11. Operating the Boiler 11.1 Operating the Boiler for the First Time FOR YOUR SAFETY READ BEFORE OPERATING WARNING: If you do not follow these instructions exactly, a fire or explosion may result, causing property damage, personal injury or loss of life. A.

  • Page 95: Turning The Boiler On Or Off

    11.2 Turning the Boiler On or Off WARNING To turn the boiler on or off, press the Power button Ensure that the boiler is filled with water ● before turning on the boiler for the first time. Turning on a boiler that is not filled will damage the boiler and result in property damage, severe personal injury, or death.

  • Page 96: Start-Up Wizard

    11.3 Start-Up Wizard 8. Set the DHW Call Signal DHW Thermostat ● The start-up wizard should run the first time the DHW Tank Sensor ● unit is powered on. The wizard must be completed before the boiler can be used. 9.

  • Page 97: Adjusting The System Temperatures

    11.4 Adjusting the System Temperatures In normal operation mode, space heating temperature for each zone can be set depending on the settings in the following table. Settings Space heating settings Zone Priority Settings Zone Settings Pump 1 Settings Disable Space heating temperature settings Space heating temperature settings Enable Zone Pump System...
  • Page 98 11.4.2 Adjusting the Space Heating Temperature (When “3. Zone Priority Setting” is enabled) To adjust the heating temperature: 1. In normal operation mode, rotate the Command dial ( ). The space heating temperature ( ) is highlighted on the screen. 2.
  • Page 99 11.4.3 Adjusting the DHW Indirect 4. Rotate the Command dial ( ) to the right or Supply Temperature left to increase or decrease the temperature. 5. Press the Command dial ( ) to confirm the To adjust the water temperature: new temperature.

  • Page 100: Accessing Basic Menu Items

    11.5 Accessing Basic Menu Items Item Description AHU Space Heating Set In the Menu Select screen, you can view the boiler’s Temperature (°F) operating conditions, configure the space heating and DHW temperatures, and review error history. If AHU is not connected, ●...
  • Page 101 Press the Back button ( ) to return to the previous Item Description screen or menu. Outdoor reset curve load type (displayed when the Item Description outdoor reset option “21. Outdoor Reset” is enabled) Set space heating target 1: Finned Tube Baseboard temperature (°F).
  • Page 102 Warm Weather Shut- the set priorities will be down. initialized. 4-5. WWSD On Diff Setting range: 0°F (0°C) If “5. Navien zone cont. ” is ● ● – 36°F (20°C) enabled, “3. Zone Priority Settings” will be disabled Default: 5°F (3°C) ●...
  • Page 103 Item Description CAUTION Select a heating control type. An outdoor sensor error may occur if the 1: Supply Temperature Outdoor Reset Control mode is enabled without 2: Return Temperature the outdoor sensor installed 3: Sys Supply Temperature 4: Sys Return Temperature In the Outdoor Reset Control mode, the Note...
  • Page 104 Press the Back button ( ) to return to the previous Item Description screen or menu. Select a DHW control type. Item Description 6. DHW control 1. Supply water method 2. Sys Supply water Set the external hot water tank temperature (°F). Default: Supply water ●...
  • Page 105 Press the Back button ( ) to return to the previous Rotate the Command dial ( ) to switch between screen or menu. the list of errors. Press the Command dial ( ) to select an error to view detailed information. Item Description 1.

  • Page 106: Accessing Advanced Menu Items

    Press the Back button ( ) to return to the previous Item Description screen or menu. Select a water pressure unit. Item Description 1. PSI 3. PSI/BAR Setting 2. BAR 1. Elapsed Time After Elapsed time since Install installation Default : PSI ●...
  • Page 107 11.6.2 Viewing Input and Output Status Item Description To view the boiler’s input and output status, press 10. Zone V/V 2 Zone 2 valve output the Back button ( ) and the Menu button ( Status status simultaneously for 3 seconds, and then select 11.
  • Page 108 In the password screen, rotate the Command dial Item Description ) to change numbers and places, and press the Command dial ( ) to enter the password. Set the temperature range to turn off space The factory default password is “1234”. heating.
  • Page 109 Item Description Item Description Set the anti-fast cycling Turn on or turn off the time. system pump in DHW 12. Anti Fast Cycling 19. Sys pump mode. Time* Setting range: 0 – 20 min ● Oper(DHW) Setting range: On/Off Default: 3 min ●...
  • Page 110 * The anti-fast cycling time is the duration that the boiler Item Description stops its space heating operation when the space heating supply or return temperatures reach the set values for Set the service boiler operation stop temperatures. The boiler will not notification according to resume space heating until the duration elapses, even the operating times.
  • Page 111 Press the Back button ( ) to return to the previous Item Description screen or menu. Select this option on the Main unit of a cascade Item Description system to end cascade operation. To enter the Cascade ● Main setting mode, Enter Cascade system ●...
  • Page 112 Press the Back button ( ) to return to the previous Item Description screen or menu. The number of units 6. Number of Oper- currently operating in the Item Description Unit cascade system. Turn on or turn off View the operating status the remote control 7.
  • Page 113 Press the Back button ( ) to return to the previous Item Description screen or menu. Test the DHW (zone 1) pump operation. Item Description The DHW (zone 1) ● Test the fan operation by pump is turned on as manually changing the 5.
  • Page 114 11.6.7 Setting the Special Operation Item Description Modes Test the zone 3 valve operation. To operate the boiler in special operation modes, press the Back button ( ) and the Menu button The zone 3 valve is ● ) simultaneously for 3 seconds, and then select turned on as soon “7.
  • Page 115 11.6.8 Operating in Air Purge Mode To operate the boiler in air purge mode, press the Back button ( ) and the Menu button ( simultaneously for 3 seconds, and then select “8. Air Purge Mode”. Rotate the Command dial ( ) to switch between the parameters.

  • Page 116: Understanding Error Codes

    11.7 Understanding Error Codes When an error code appears on the front panel, refer to the following chart for a definition and possible remedy for the situation. Error Code Reason Self-diagnostic/Action E001 Heat exchanger over temperature Auto reset/Manual reset E003 Ignition failure Manual reset E004...

  • Page 117: Appendixes

    ● without an officially approved conversion kit mixes an odorant with the propane to make and the instructions supplied by Navien. Gas its presence detectable. In some instances the & High Altitude conversion using any other odorant can fade, and the gas may no longer parts will result in extremely dangerous burner have an odor.
  • Page 118 Included Items: Gas Orifice (Table 1) ● Gas Pressure and Conversion Kit Number Labels ● NFB-175H, NFB-200H Orifice Identification Propane Natural Gas Type 5,400- Altitude 5,399 ft 10,100 ft 10,100 ft Orifice GAS : NG GAS : NG(H) GAS : LP...
  • Page 119 Location B: Remove injury, death or substantial property damage. 4 screws here Navien NFB-H boilers are shipped ready to fire natural gas ONLY. Location A: Remove the clip here Figure 3.
  • Page 120 GAS : LP 20052127A 20052133A 20052143A 4.8 / 7.90 5.05 / 8.4 3.90 / 6.00 <NFB-175H, NFB-200H Orifice Identification> Figure 6. Orifice Identification Switch Function Setting Comment Natural Gas 1-OFF 8. Remove the Gas Orifice, ensure that the packing Gas Type...
  • Page 121 1 & 2 Status in severe personal injury or death. 1-stage MIN 1-OFF, 2-ON 1-stage MAX 1-ON, 2-ON 11. Turn on the gas and water supply to the boiler. NFB-200H 5-OFF, 6-OFF Model 5 & 6 Setting NFB-175H 5-ON, 6-OFF Appendixes...
  • Page 122 d. Activate multiple zones and set the boiler High fire Low fire Model Altitude Fuel to operate at 2-stage D. MAX mode (refer to “11.6.7 Setting the Special Operation Natural Modes” on page 114). Measure the CO value at high fire. 0-5,399 ft Propane NFB-...
  • Page 123 c. Activate multiple zones and set the boiler 13. Once the CO or offset values have been to operate at 1-stage MIN mode (refer confirmed, apply the included conversion to “11.6.7 Setting the Special Operation stickers to show that the appliance has been Modes”...

  • Page 124: Wiring Diagram

    12.2 Wiring Diagram DHW Tank **Temp Sensor Outdoor **Temp Sensor System Return **Temp Sensor System Supply **Temp Sensor CNB1 124 Appendixes...

  • Page 125: Ladder Diagram

    12.3 Ladder Diagram AC INPUT(AC 120V) AC INPUT(AC 120 V) LIVE NEUTRAL LIVE NEUTRAL Terminal Board Relay 1 Boiler Pump Dual Venturi Relay 5 Relay 2 Relay 6 FILTER ZONE1 Pump (DHW Tank) Relay 3 Ignitor ZONE2 Pump Relay 4 Speed Control ZONE3 Pump (System)

  • Page 126: Outdoor Temperature Sensor

    When necessary, shielded cable may be used. Make sure wiring connections are secure before ● closing the cap. Navien Outdoor Temperature Sensor Kit The sensor is a water resistant device. ● Any damage to the device may require the ●...
  • Page 127 Outdoor Outdoor High MIN Low MIN °F °C Absolute High Mass Radiant Low Mass Radiant Cast Iron Baseboard Custom Radiator Finned Tube Baseboard Fan Coil Absolute °F 113 104 95 86 77 68 59 50 32 23 14 -4 -13 °C 45 40 35 30...

  • Page 128: Component Assembly Diagrams And Parts Lists

    12.6 Component Assembly Diagrams and Parts Lists 12.6.1 Case Assembly 128 Appendixes...
  • Page 129 Description Service code Part # Remark Case Upper 20050476* Case Middle 20041094* Case Lower 20050477* Cover 30027115A 30026127* Drain Pan Adapter Lower Bracket 30025980* Heat Exchanger Bracket 20040243* Bolt (Ø4x10) 20038757* Base Bracket 20007609* Screw (Ø4x6) 20038859* PCB Lower Bracket 20041079* Screw (Ø4x8_S/W) 20044834*...
  • Page 130 12.6.2 Heat Exchanger and Waterway Assembly 130 Appendixes...
  • Page 131 Description Service code Part # Remark Heat Exchanger Assembly 30021656A 30021564* Drain Pan Assembly 30019173A 20040239* Drain Pan Packing 30019173A 20040241* Exhaust Duct (Lower) 30019174A 20040242* Exhaust Duct Clip 30019174A 20042741* Exhaust Duct Packing (G90) 30019174A 20027350* Exhaust Duct Packing (P85) 30019174A 20042823* Exhaust Duct Adaptor...
  • Page 132 12.6.3 Combustion Parts Assembly Description Service code Part # Remark Fan Assembly 30019826A 30026225* Venturi Packing 20018079* Dual Venturi 30027110A 30026308* Intake Pipe 30019120A 30019120* Screw (Ø4x10) 20034293* 132 Appendixes...
  • Page 133 Description Service code Part # Remark Orifice Packing 20022600A 20022660* 20052127A 20052127* NFB,C-175H/200H (NG) Gas Orifice 20052133A 20052133* NFB,C-175H/200H (NG,H) 20052134A 20052134* NFB,C-175H/200H (LP) Bolt (Ø3x5) 20006365* O-ring (P34) 20019090* Gas Connector (Upper) 20051616* Screw (Ø4x12_S/W) 20043077A 20043077* O-Ring (P18) 20023434A 20023434* Fastener...
  • Page 135 Installation Manual NFB-H Condensing Boilers 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.navieninc.com. ● For warranty service, always contact Technical Support first. ● Contact the technician or professional who installed your boiler. ●...

This manual is also suitable for:

Nfb-200h

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