Navien NHB Series Installation & Operation Manual Download Page 78

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Installing a Common Vent System

9.3 Starting the Common Vent System

9.3.1 Backflow Damper Assembly

Follow the instructions below to assemble the backflow damper
on the NFB boiler unit:

1. Remove the screws from the exhaust vent adapter.

2. Detach the exhaust vent adapter.

3. Connect the backflow damper to the exhaust duct of the boiler

unit.

4. Tighten the four mounting screws to secure the backflow

damper in place. The screws (x 4) are supplied with the
backflow damper.

Summary of Contents for NHB Series

Page 1: ...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 qua...

Page 2: ...s located in a crawl space unless the appliance is located in a detached uninhabitable garage For all residential dwellings a carbon monoxide detector must also be present on each habitable level of t...

Page 3: ...1 DIP Switch 1 6 switch unit 63 6 2 DIP Switch 2 8 switch unit 63 7 Connecting the Power Supply 64 8 Installing a Cascade System 65 8 1 Connecting Water Supplies 65 8 2 Connecting the Communication C...

Page 4: ...bor s phone call your gas provider and follow their instructions If you cannot reach your gas provider call the fire department Do not return to your home until authorized by your gas supplier or the...

Page 5: ...WARNING Do not store or use gasoline or other flammable liquids near this boiler Doing so may result in fire or explosion Do not place combustibles such as newspapers or laundry near the boiler or ve...

Page 6: ...ief Valve Heating Conversion Kit Outdoor Temperature Sensor and Cable Air Vent Bushing with Gasket 1 in to in NFB 301C 1 in to in NFB 399C Condensate Trap 1 About the Boiler Universal Temperature Sens...

Page 7: ...BH Thermal Efficiency2 Boiler Water Content Gallons Water Pressure Water Connection Size Supply Return Min Max NFB 301C 20 301 293 255 97 5 7 6 12 160 psi 1 in NPT NFB 399C 26 399 389 338 97 5 9 6 1 i...

Page 8: ...Materials Casing Cold rolled carbon steel Heat Exchangers Stainless Steel Venting Exhaust 3 in or 4 in PVC CPVC approved polypropylene approved stainless steel 3 in or 4 in Special Gas Vent Type BH C...

Page 9: ...n the Appendixes Intake Air Air Intake Pipe Exhaust Optional Heating Return Fan Motor Assembly Dual Venturi Gas Pipe PCB 24V Power Transformer Power Switch PRV Air Vent Connection Optional Heating Sup...

Page 10: ...ional Heating Return Fire Tube Type Heat Exchanger Gas Pipe Power Switch Heating Return Gas Valve ASME Name Plate Mixing Chamber Internal Air Filter PRV Air Vent Connection Optional Heating Supply Hea...

Page 11: ...in B Exhaust Gas Vent 3 in C PRV Air Vent Connection Optional Heating Supply 11 4 in 11 2 in D Optional Heating Return 11 4 in 11 2 in E Heating Supply 11 4 in 11 2 in F Condensate Outlet 3 4 in G He...

Page 12: ...3 mm 18 9 480 6 mm 21 534 2 mm 22 4 568 mm 14 3 364 4 mm 8 5 217 mm 25 2 640 mm 3 1 78 5 mm 16 7 423 1 mm 14 3 362 1 mm E G H F 16 5 420 mm 3 2 81 mm 18 4 468 mm 22 560 mm 22 3 566 mm 17 2 436 mm 2 9...

Page 13: ...ons at altitudes up to 10 100 ft 3 078 m follow the directions provided in the High Altitude Installations sections of the lnstallatlon Manual toutes les proc dures d installation haute altitude CAN C...

Page 14: ...Pallet Brackets 1 Remove the L and R boxes Note Do not discard the L box as it contains the wall mounting bracket and the anti vibration rubber pad 2 Loosen the eight screws that secure the wood palle...

Page 15: ...be near where the domestic water supply enters the building Gas the installation location should be near where the gas supply enters the building Electricity the installation location should be near w...

Page 16: ...For more information about venting refer to 5 Venting the Boiler on page 52 To ensure adequate venting and ventilation follow these guidelines Maintain proper clearances from any openings in the build...

Page 17: ...UTION It is necessary to leave clearance for service access Clean Debris and Chemical free Combustion Air Do not install the boiler in areas where dust and debris may accumulate or where hair sprays s...

Page 18: ...om end after removing it from the shipping carton Doing so may result in excessive pressure on protruding pipes and resulting in product damage If you must put the boiler down lay it on its back or pu...

Page 19: ...rty damage fire serious injury or death 3 Installing the System Piping 3 1 1 Guidelines for a Space Heating Installation Read and follow the guidelines listed below to ensure safe and proper installat...

Page 20: ...tion WARNING Immediately repair any leaks in the system piping to avoid adding make up water Make up water adds oxygen and minerals to the system that may lead to heat exchanger failure Failure to fol...

Page 21: ...er installing the air vent bushing to the air vent connection and inserting the PRV air vent adapter into the air bushing install the provided clip between the air vent bushing and the PRV air vent ad...

Page 22: ...r vent adapter Backflow Preventer Install a backflow preventer valve in the make up water supply to the unit as required by local codes ExpansionTank An expansion tank must be installed in the space h...

Page 23: ...greater than the maximum pressure rating of the boiler s space heating system Ensure that the maximum BTU H rating on the pressure relief valve is equal to or greater than the maximum input BTU H rati...

Page 24: ...g NFB 301C 20 F UPS26 150 2400 60 NRF 36 E8 2 25 F UPS26 150 0013 NRF 36 E7 2 35 F UPS26 99 0010 NRF 36 E7 2 NFB 399C 20 F UPS26 150 2400 60 NRF 45 E11 2 25 F UPS26 150 0013 NRF 45 E8 2 35 F UPS26 99...

Page 25: ...C NFB 301C Q GPM 0 0 5 0 11 5 14 5 17 0 19 0 22 0 25 0 28 0 30 0 32 5 H ft 0 0 0 7 2 0 3 0 4 0 4 5 6 0 7 8 9 9 11 0 12 6 0 1 2 3 4 5 6 0 5 10 15 20 25 30 35 40 45 H ft Q GPM NFB 399C NFB 399C Q GPM 0...

Page 26: ...ol concentration increases The corrected flow rate and head loss values below must be used when sizing the boiler pump in order to maintain similar performance as using 100 water for the heating syste...

Page 27: ...recommend draining the condensate into a laundry tub as the alkali in laundry detergent will neutralize the acid in the condensate However other suitable waste drain locations may be used according t...

Page 28: ...ng distance between the boiler and the laundry tub or when the bottom of the boiler is lower than the top of the laundry tub To connect the condensate drain 1 Connect a drain line to the 3 4 infitting...

Page 29: ...ess to the discharge connection is required for maintenance and pH testing If there is insufficient gradient for drainage install a drainage pump designed for boiler and water heater condensate remova...

Page 30: ...system has been installed properly Follow the instructions below to perform a leak test on the water system 1 Fill the system only after ensuring that the water chemistry meets the requirements Conta...

Page 31: ...ide a system expansion tank following the guidelines on page 22 System installations must comply with all local codes Air Removal The boiler and system piping layout must be configured to promote the...

Page 32: ...y Air Handler Interface The Navien NFB boiler can control the operation of an air handler when a thermostat is used in combination with the air handling unit The Air Handler Interface is designed to s...

Page 33: ...re intended to explain the system piping concept only Install a filter in the system return to remove foreign objects from the system Foreign objects inside the system may result in abnormal system op...

Page 34: ...oreign objects from the system Foreign objects inside the system may result in abnormal system operation Refer to 3 3 Filling the System on page 29 for make up water connections and refer to the requi...

Page 35: ...eparator Note System application drawings are intended to explain the system piping concept only Install a filter in the system return to remove foreign objects from the system Foreign objects inside...

Page 36: ...Wiring errors can cause improper and dangerous operation Verify proper operation after servicing Note The installation must comply with National Electrical Code and any other national state provincia...

Page 37: ...5 5 7 6 2 9 91 RLOHU 3XPS 21 3803 21 3803 21 3803 B 1 B287 B 1 B287 B 1 1 B287 12 B287 20 B 1 B287 RLOHU 6WDWH RLOHU UURU 35 RLOHU 3XPS 21 3803 21 3803 21 3803 B 1 B287 B 1 B287 B 1 1 B287 12 B287 20...

Page 38: ...B 1 B287 RLOHU 6WDWH RLOHU UURU 35 5 7 6 21 7 6 21 7 6 21 5 5 9 1 7KHUPRVWDW QSXW 9 9 1 7KHUPRVWDW QSXW 9 9 1 7KHUPRVWDW QSXW 9 9B1 9B1 9B 9B 9B1 9B 9B1 9B Boiler Pump Zone Pump 1 Zone Pump 2 Zone Pu...

Page 39: ...B 1 B287 B 1 1 B287 12 B287 20 B 1 B287 RLOHU 6WDWH RLOHU UURU 35 RLOHU 3XPS 21 3803 21 3803 21 3803 B 1 B287 B 1 B287 B 1 1 B287 12 B287 20 B 1 B287 RLOHU 6WDWH RLOHU UURU 35 5 7 6 21 7 6 21 7 6 21...

Page 40: ...6 21 7 6 21 7 6 21 5 5 5 7 6 9 1 7KHUPRVWDW QSXW 9 9 1 7KHUPRVWDW QSXW 9 9 1 7KHUPRVWDW QSXW 9 9B1 9B1 9B 9B 9B1 9B 9B1 9B Boiler Pump DHW Pump Zone Pump 2 Zone Pump 3 Pump Ground Thermostat 1 Thermo...

Page 41: ...y by minimizing unnecessary pump operation The communication link also provides an optimal control environment for freeze protection 18 7 6 2 6 7 1387 7 03 5 785 6 1625 3 6 287 225 7 1 a 9 1 a 9 287 6...

Page 42: ...2 B287 20 B 1 B287 9B1 9B 9B 9B1 Pump Ground 3 6 6 Wiring Diagram Generic Zone System with Circulators RLOHU 3XPS 21 3803 21 3803 21 3803 B 1 B287 B 1 B287 B 1 1 B287 12 B287 20 B 1 B287 RLOHU 6WDWH R...

Page 43: ...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 DHW tank before installing t...

Page 44: ...lief Valve Air Vent Air Vent Bushing Note To control the boiler supply or return water temperature using the external temperature sensors configure the system accordingly On the front panel tap the Co...

Page 45: ...ton Ext Connection on the screen and then select N Open Normal open type or N Closed Normal closed type 3 7 Connecting External devices Field Wiring Guidelines To connect external devices to the contr...

Page 46: ...ted external safety device tap the Set button Ext Connection on the screen and then select N Open Normal open type or N Closed Normal closed type on the Auto Reset Safety Switch menu 3 7 9 Modbus BACn...

Page 47: ...d to be the first appliance to be connected to the gas supply line Gas meter capacity The total capacity of connected appliances Gas Supply Line To connect the gas supply 1 Determine the gas type and...

Page 48: ...pipe Navien recommends the installation of a union on the gas supply line close to the boiler to facilitate any future maintenance or service CAUTION Prior to using an excess flow valve EFV in the ga...

Page 49: ...3 020 2 680 2 430 2 230 2 080 1 950 1 840 1 630 3 in 11 300 7 780 6 250 5 350 4 740 4 290 3 950 3 670 3 450 3 260 2 890 4 in 23 100 15 900 12 700 10 900 9 660 8 760 8 050 7 490 7 030 6 640 5 890 In Cu...

Page 50: ...2 370 2 200 2 070 1 950 1 730 1 570 1 440 4 2 Measuring the Inlet Gas Pressure WARNING The boiler cannot function properly without sufficient inlet gas pressure Measuring the inlet gas pressure should...

Page 51: ...ure must fall within the ranges specified on page 8 To measure the inlet gas pressure 1 Shut off the manual gas valve on the gas supply line Gas Valve Opened Closed 2 Turn on the boiler On the front p...

Page 52: ...ect venting to supply air from outside the building We recommend regular filter cleaning and maintenance in these areas For best results keep the venting system as short and straight as possible Locat...

Page 53: ...es to air intake restrictions are observed Do not store hazardous or flammable substances near the vent termination If this boiler will be installed in areas where snow is known to accumulate protect...

Page 54: ...f ABS PVC CPVC PP galvanized steel corrugated aluminum or any other such materials If you use a corrugated material ensure that there is not inadvertent crimping of or damage to the intake air pipe Wh...

Page 55: ...sibility of back drafting in the installation location use a direct venting system for the boiler When using non direct venting maintain non direct vent clearances shown on page 56 as required by ANSI...

Page 56: ...ator vent outlet 36 in 91 cm J Clearance to non mechanical air supply inlet to building or the combustion air inlet to any other appliance 36 in 91 cm 48 in 120 cm below or to side of opening 12 in 30...

Page 57: ...ropylene or Stainless Steel in the USA or Type BH Special Gas Vent Class IIB CPVC or Class IC Polypropylene Stainless Steel that conforms to ULC S636 in Canada In systems with 3 in vents if the exhaus...

Page 58: ...45 m The intake duct length may be identical to the exhaust duct length Maximum vent lengths reduces according to the number of elbows used as shown in the following table Vent Size Maximum Length Ma...

Page 59: ...ile terminations only Clearance above highest anticipated snow level or grade or as required by local codes whichever is greater Note Only the following orientations are allowed for twin pipe terminat...

Page 60: ...ent Combustion Air Combustion Air Indoor Boiler Installation Venting Examples continued Non Concentric Sidewall Venting Air is drawn from a different location that is at least 12 in 300 mm away from t...

Page 61: ...er 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 all...

Page 62: ...is included Additional filters can be ordered through authorized Navien distributors CAUTION If the air filter is not replaced it may result in poor performance for the boiler If the internal air filt...

Page 63: ...ch 2 8 switch unit The DIP SW 2 on the circuit board configures the gas type country and enables or disables the space heating thermostat 1 2 3 4 5 6 O N O N 1 2 3 4 5 6 7 8 Switch Function Setting 1...

Page 64: ...ternal pump to the boiler connect it to the external pump terminal of the boiler PCB Connect the wires referring to the following table The pump ground should be connected to the boiler and the buildi...

Page 65: ...sensors required Cold water Supply Return Back flow preventor Expansion tank NFB 301C 399C Note System application drawings are intended to explain the system piping concept only Install a filter in t...

Page 66: ...nk Note Connect the SH Demand SH T T or Zone controller to the main unit Connect the universal temperature sensors to SUPPLY and RETURN terminals of the CNT1 CNT2 terminal strip on the main unit PCB C...

Page 67: ...sion tank Temperature sensors required Note Connect the SH Demand SH T T or Zone controller to the main unit Connect the universal temperature sensors to SUPPLY and RETURN terminals of the CNT1 CNT2 t...

Page 68: ...is feature tap the Control button SH Control and set the Zone Setting to OFF Connect the zone pump to the main unit or subunit and connect the SH Demand SHT T to the zone that the pump is connected to...

Page 69: ...he main unit Depending on the installation environment the supply top and return top piping option can be applied System Application 5 Cascade System with DHW Indirect Tank Sub2 Sub1 Main Cold water S...

Page 70: ...ment of the indirect tank shall not exceed the capacity of the single boiler Connect the DHW pump to the sub unit System Application 7 Cascade System with DHW Indirect Tank for Low DHW Demand Temperat...

Page 71: ...ables restore power to the boiler and turn on all boilers using the Power button To configure the communication settings refer to 11 6 4 Configuring a Cascade System on page 103 8 1 1 Piping Sizes and...

Page 72: ...common vent systems or consult Navien Use only the PVC cements specified in this manual when connecting pipes joints or elbows Position the boiler units as close as possible to the vent termination In...

Page 73: ...um Back 0 5 in 13 mm minimum Front 24 in 610 mm minimum Sides 6 in 152 mm minimum Bottom 16 in 406 mm minimum CAUTION It is necessary to leave clearance for service access Clean Debris and Chemical Fr...

Page 74: ...Comply with all relevant regulations Cutting and Assembling CommonVent System Components Standard tools are suitable for the cutting and assembly of common vent system components Follow the guideline...

Page 75: ...g Twisting the pipe spreads the solvent cement evenly to ensure a solid joint 3 Hold the pipe and pipe fitting together for about 15 seconds until the cement sets Note Use approved solvent type cement...

Page 76: ...al height H Total length L W H H W D Intake Exhaust Note Every 90 elbow used is equivalent to 8 linear feet 2 4 m of vent length The pipe branch that connects the individual appliance to the common ve...

Page 77: ...explosion may result causing property damage personal injury or death Condens ing Water Heater Common Vent System Installation Manual For NPE Series Water Heaters Certified to ANSI Z21 10 3 CSA 4 3 On...

Page 78: ...assemble the backflow damper on the NFB boiler unit 1 Remove the screws from the exhaust vent adapter 2 Detach the exhaust vent adapter 3 Connect the backflow damper to the exhaust duct of the boiler...

Page 79: ...per 1 Measure 3 1 8 from the end of the vent pipe then draw a mark at that distance Mark 3 1 8 from the end of the pipe 3 1 8 2 Insert the vent pipe into the vent collar to start the vent run Make sur...

Page 80: ...se personal injury or death After completing the installation and filling the boiler with water turn on the boiler and test for leaks using a bubble test kit After applying the soap solution bubbles w...

Page 81: ...t or wye assembly Each trunk pipe is connected to the other wye joint or wye assembly Refer to Connecting Pipes with Cement on page 75 for more information Note The pipe branch that connects the indiv...

Page 82: ...vent type referring to the following table Item Description Vent type Set the ventilation type Setting range Common Individual Default Common Note For more information on the vent type settings refer...

Page 83: ...warmer than the ambient air Therefore you will see water vapor being produced at the termination 9 6 3 DirectVent Application Horizontal Installation Exhaust Gas 12 300 mm min 12 300 mm min Intake Ai...

Page 84: ...se to the cascade system and direct the end of the hose to a drain WARNING After installing the condensate drain hose check the loop again to ensure that the prime water is not spilled The loop siphon...

Page 85: ...arance to service regulator vent outlet 3 ft 91 cm J Clearance to nonmechanical air supply inlet to building or the combustion air inlet to any other appliance 36 in 91 cm 12 in 30 cm K Clearance to a...

Page 86: ...the gasket is not installed or if it is not installed properly Gasket 9 9 Maintenance Periodically check the damper condition inside the backflow damper through the maintenance port to ensure optimal...

Page 87: ...apors Is the boiler and vent piping clear of combustible materials including clothing cleaning materials and rags Connecting the Gas Supply Yes No Does the gas supply match the type specified on the b...

Page 88: ...accordance with all local codes and the guidelines in this manual Have you ensured that ABS or PVC cellular core pipe has not been used as venting for the boiler Is the vent sloped upward toward the v...

Page 89: ...equired 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 Operating the boiler Yes No Have you given the Installa...

Page 90: ...ff tap DHW ON on the top right of the screen 11 1 Turning the Boiler on or off To turn the boiler on 1 Connect the power cord When the power is on the User Settings screen is displayed 2 Select the la...

Page 91: ...ting the Space HeatingTemperature To adjust the heating temperature on the screen tap or to select the space heating temperature in the SH Set Temp menu The current temperature setting is displayed in...

Page 92: ...r the operating status displays that appear when using the boiler Item Operating Status Displays Description Standby The boiler is on standby for a new operation Start Up The boiler operation has star...

Page 93: ...PM Set fan speed RPM 14 Current RPM Fan speed RPM 15 Target APS Set APS voltage V 16 Current APS APS voltage V 11 5 2 Setting the Space Heating Operation To set the boiler s space heating operation ta...

Page 94: ...Setting is enabled you can set the temperature for each zone and each zone will be controlled by the set temperature If simultaneous demands for several zones occur the temperature will be controlled...

Page 95: ...sed DHW Tanks Set Temp 18 F 10 C 194 F 90 C Default 180 F 82 C 6 DHW Priority time Set the DHW priority time Setting range 0 180 min Default 30 min Item Description 4 Curve select Select the outdoor r...

Page 96: ...growth of legionella bacteria in the DHW tank only It will not protect water supply piping A mixing valve must be installed on the DHW supply line when this mode is enabled as water temperatures will...

Page 97: ...t Default Firing Rate 6 BMS Enable Volts Set the BMS activation voltage Boilers operates when the input voltage exceeds the set voltage Setting range 0 V 10 V Default 2 V 11 5 6 Setting General Buildi...

Page 98: ...lash drives cannot be used for memory backup Item Description 7 BMS off Differential Set the BMS off differential voltage Boiler stops operating when the input differential voltage is lower than the s...

Page 99: ...r overheating protection activation 3 Flame Loss No of times Number of flame loss misfire 4 2nd ignition No of times Number of second ignition 5 3rd ignition No of times Number of third ignition 6 4th...

Page 100: ...HTL Input HTL input status 10 Dual Venturi Output Dual Venturi output status 11 LWCO Input LWCO input status 12 Air Handler Output Air Handler Interface output status 13 DHW Priority Output DHW prior...

Page 101: ...ace heating Setting range 2 F 1 C 54 F 30 C Default 5 F 3 C 7 SH Min Limit Set space heating minimum heat capacity limit Setting range Space heating Min capacity space heating min capacity limit 20 De...

Page 102: ...ng time is the duration that the boiler stops its space heating operation when the space heating supply or return temperatures reach the set values for boiler operation stop temperatures The boiler wi...

Page 103: ...Applied if Operation Strategy is set to Custom Setting range Unit Off HC 20 Max Cascade heat 5 Default 70 11 6 4 Configuring a Cascade System To view and configure the cascade settings tap the Set bu...

Page 104: ...shortest uptime during the time set in Lead Rotation Period Default ID Item Description 3 Force Lead Change Set Force Lead Change Yes Reassign the lead boiler regardless of the demand status No Reassi...

Page 105: ...of Unit On HC Default 70 Unit Off HC The value of Unit Off HC Default 30 Feature Minimizes switches from On Off in the unit Maximizes the unit operation Minimizes the unit operation On Off in the uni...

Page 106: ...all amount of load changes Small On Off gap 95 47 5 47 5 95 95 63 3 60 63 3 63 3 100 100 100 45 45 30 30 30 30 30 Unit ON Unit ON Unit OFF Unit OFF 60 30 30 60 60 40 40 40 Boost This mode minimizes th...

Page 107: ...pump3 Test the pump3 operation The pump3 is turned on as soon as you enter the test mode Tap ON or OFF to toggle the pump operation ON OFF OFF ON 6 dual venturi Test the dual venturi operation The dua...

Page 108: ...boiler to run in 1st step maximum operation mode 4 2Step MIN Set the boiler to run in 2nd step minimum operation mode 5 2Step MAX Set the boiler to run in 2nd step maximum operation mode 11 6 8 Opera...

Page 109: ...y thermistor Auto reset E218 Abnormal operation heating return thermistor Alarm E278 Abnormal operation system supply thermistor Alarm E279 Abnormal operation system return thermistor Alarm E291 Suppl...

Page 110: ...stallation Code Tools Required Phillips Screwdriver Flathead Screwdriver 5 32 in or 4 mm Allen Wrench T40 or 6 65 mm Star Wrench Combustion Analyzer or Dual Port Manometer Gas Leak Detector Included I...

Page 111: ...tion above the gas valve where it connects to the gas valve outlet adapter See Figure 3 for reference 6 Find location B the connection above the gas valve where it is attached to the fan motor assembl...

Page 112: ...led The O ring must be in good condition and must be installed Failure to comply will cause a gas leak resulting in severe personal injury or death Figure 6 Orifice Identification 8 Remove the Gas Ori...

Page 113: ...the power to the boiler before accessing the DIP switches 1 2 3 4 5 6 O N O N 1 2 3 4 5 6 7 8 Switch Function Setting Comment 1 GasType Natural Gas 1 OFF Refer to Table 1 on page 110 Propane Gas 1 ON...

Page 114: ...ection refer to 11 6 7 Setting the Operation Modes on page 108 Measure the CO2 value at low fire If the CO2 value is not within 0 5 of the value listed in Table 2 the gas valve set screw will need to...

Page 115: ...ation Note The set screw is located behind the screw on cover This must be removed first d At high fire do not check the offset value and never adjust the gas valve DANGER Improper gas valve settings...

Page 116: ...ive Live LWCO AC24V T S INPUT T S_2 AC24V T S INPUT T S_3 T S_4 AC24V T S INPUT Manual Reset Safety Switch E774 Power Trans AC_L IN OUT AC_N AC_L IN OUT AC_N AC_L IN OUT Ground Ground Ground NO COM 0...

Page 117: ...ity Flame Rod Linear Trans AC 24V AC INPUT AC 120V Terminal Board 3 15A Auto AC Gas Valve NFB 399C Boiler State Boiler Error Relay 4 Boiler Pump Relay 1 10A 10A 10A 10A ZONE1 Pump Relay 3 ZONE3 Pump R...

Page 118: ...sor is on a North or Northeast side of a structure under eaves where the sensor is shielded from direct sunlight Avoid placing sensor in close proximity of heat sources that may affect correct tempera...

Page 119: ...automatically changes according to the outdoor temperature and the current space heating system application system load You can configure the Outdoor Reset Control settings on the front panel Refer t...

Page 120: ...120 Appendixes 12 6 Component Assembly Diagrams and Part Lists 12 6 1 Case Assembly NFB 301C...

Page 121: ...ain PCB 30020431A 3 2 Terminal PCB 30020433A 4 Front Panel 30019786A 5 Exhaust Duct Assembly 30020520A 6 Intake Air Duct Assembly 30020519A 7 1 Air Filter Case 20046047A 7 2 Air Filter 20046201A 8 PCB...

Page 122: ...122 Appendixes 12 6 2 Case Assembly NFB 399C...

Page 123: ...ain PCB 30020431A 3 2 Terminal PCB 30020433A 4 Front Panel 30019786A 5 Exhaust Duct Assembly 30020520A 6 Intake Air Duct Assembly 30020519A 7 1 Air Filter Case 20046047A 7 2 Air Filter 20046201A 8 PCB...

Page 124: ...124 Appendixes 12 6 3 Heat Exchanger and Waterway Assembly NFB 301C...

Page 125: ...020587A 12 Return Pipe Lower 30022921A 13 Thermistor 30012907A 14 Return Pipe Upper 30022922A 15 Drain Pan Packing 20040241A 16 Exhaust Duct Lower 20040242A 17 Exhaust Duct Clip 20042741A 18 Exhaust D...

Page 126: ...126 Appendixes 12 6 4 Heat Exchanger and Waterway Assembly NFB 399C...

Page 127: ...eturn Pipe Lower 30020993A 13 Thermistor 30012907A 14 Return Pipe Upper 30020585A 15 Drain Pan Packing 20040241A 16 Exhaust Duct Lower 20040242A 17 Exhaust Duct Clip 20042741A 18 Exhaust Duct Packing...

Page 128: ...128 Appendixes 12 6 5 Combustion Parts Assembly NFB 301C...

Page 129: ...043015A NFB 301C LP 20046180A NFB 301C NG High Altitude Nozzle 20046181A NFB 301C LP High Altitude Nozzle 9 Gas Connector Packing 20042800A 10 Gas Connector Upper 20042238A 11 Fastener 20007878A 12 O...

Page 130: ...2386A 41 Screw M4 12 Spring Washer 20043077A 42 Screw M4 10 Spring Washer 20038759A 43 Screw M3 5 20006365A 44 Screw M6x12 Spring Washer 20043735A 45 Screw M4 6 20027618A 46 Screw M4 10 20038757A 47 S...

Page 131: ...131 Appendixes 12 6 6 Combustion Parts Assembly NFB 399C...

Page 132: ...A NFB 399C LP 20046183A NFB 399C NG High Altitude Nozzle 20046184A NFB 399C LP High Altitude Nozzle 9 Gas Connector Packing 20042800A 10 Gas Connector Upper 20043187A 11 Fastener 20017724A 12 O ring P...

Page 133: ...4 12 Spring Washer 20043077A 43 Screw M3 5 20006365A 44 Screw M4 10 Spring Washer 20038759A 45 Screw M5 12 Spring Washer 20043733A 46 Screw M6x12 Spring Washer 20043735A 47 Screw M4 6 20027618A 48 Scr...

Page 134: ...Memo...

Page 135: ...ct a licensed professional for the affected system for example a plumber or electrician When you contact Technical Support please have the following information at hand Model number Serial number Date...

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