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Navien NCB-150E, Service Manual

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Navien NCB-150E Service Manual Download Page 65

Version 1.4

64        NCB-E Service Manual

4.9    Key Components Description

4.9.1    PCB

Part

Check Point

Function

To control each component and also to check the overall performance of the unit.

Failure Event

Malfunctioning PCB.

Effects

A component may not operate within the unit and could produce an error code. In most cases of 

PCB failure, the whole unit will not operate until the problem is resolved.

Error Code

E515, E615

Diagnostic

Visual inspection: Connection and/or breakage of wires and/or burn marks on the PCB.

Color/Number of wires

Refer to page 60-63

Summary of Contents for NCB-150E

Page 1: ...r Contact 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 numb...

Page 2: ...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 Z2...

Page 3: ......

Page 4: ...2013 1 10 Cascade information addition January 03 2014 1 20 E001 information addition E205 information revision June 12 2014 1 30 AFUE Change November 24 2014 1 40 NCB 150E 180E 210E and 240E Model Ad...

Page 5: ...ies Models 58 4 5 Version Display 59 4 6 Error Codes 59 4 7 Ladder Diagram 60 4 8 Electrical Diagnostic Point Wiring Diagram 61 4 9 Key Components Description 64 4 9 1 PCB 64 4 9 2 High Limit Switch 6...

Page 6: ...sor 140 6 2 10 Circulation Pump 141 6 2 11 3 way Valve 142 6 2 12 Water Pressure Sensor 143 6 2 13 Space Heating Strainer 143 6 2 14 Auto Feeder Valve 144 6 2 15 DHW Heat exchanger 144 7 Components Di...

Page 7: ...ner to secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors a In the event that the side wall horizontally vented gas fueled equipment i...

Page 8: ...Any damage malfunction or failure caused by abuse negligence alteration accident fire flood freezing wind lightning and other acts of God Operating using or storing the boiler in a corrosive or contam...

Page 9: ...altitudes de 0 4 500 pieds 1 370 m conform ment aux toutes les proc dures d installation haute altitude CAN CGA 2 17 une pression normale Pour les installations l vations en haut de 4 500 pieds appel...

Page 10: ...AP Air Pressure APS Air Pressure Sensor DHW Domestic Hot Water FM Fan Motor GARC Gas Air Ratio Control GPM Gallons Per Minute MGV Main Gas Valve RPM Revolutions Per Minute PCB Printed Circuit Board EM...

Page 11: ...utions DANGER FLAMMABLE MATERIALS Keep the area around the boiler clear and free from flammable materials DO NOT place flammable liquids such as oils or gasoline etc near the boiler DO NOT place combu...

Page 12: ...Failure to follow the Venting Section of the installation manual may result in unsafe operation of this boiler To avoid the risk of fire explosion or asphyxiation from carbon monoxide never operate th...

Page 13: ...2 Installation Code Navien America Inc is not liable for any property damage and or personal injury resulting from unauthorized conversions DANGER INSTALLATION REQUIREMENTS Installation conditions ma...

Page 14: ...void the manufacturer s warranty Should overheating occur or the gas supply fail to shut off turn off the manual gas valve to the appliance Do not use this appliance if any part has been under water I...

Page 15: ...00 BTU H 120 000 BTU H NCB 180E 80 000 BTU H 150 000 BTU H NCB 210E 100 000 BTU H 180 000 BTU H NCB 240E 120 000 BTU H 199 900 BTU H The appliance always gives priority to DHW supply Navien features t...

Page 16: ...s the key components of the boiler Component assembly diagrams and particular parts lists are included in the Appendixes Intake Air Exhaust Flue Duct Igniter Flame Rod Condensate Trap Auto Feeder Make...

Page 17: ...witch Air Pipe Gas Pipe APS Air Vent Circulation Pump 3 Way Valve Space Heating Supply Space Heating Return Ignition Transformer Premix Burner Primary Heat Exchanger Secondary Heat Exchanger Pressure...

Page 18: ...the same for natural gas models converted to propane use 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...

Page 19: ...in WC 0 98 in WC Gas Connection Size 3 4 in NPT Power Supply Main Supply 120V AC 60Hz Maximum Power Consumption 200W max 2A Materials Casing Cold rolled carbon steel Heat Exchangers Primary Heat Excha...

Page 20: ...ke 2 in C Exhaust Gas Vent 2 in D Space Heating Supply 1 in E Space Heating Return 1 in F Hot Water Outlet DHW 3 4 in G Gas Supply Inlet 3 4 in H Cold Water Inlet DHW 3 4 in I Condensate Outlet 1 2 in...

Page 21: ...the functions of the DIP switches and their settings Ex DIP Switch On Off Switch Function Setting 1 2 Operation Status Normal 1 OFF 2 OFF Forced Max 2 stage 1 ON 2 OFF Forced Min 1 stage 1 OFF 2 ON 1...

Page 22: ...m of altitude gain This boiler may be installed at elevations up to 10 100 ft 3 078 m for use with Natural Gas and 4 500 ft 1 370 m for use with Propane To use the boiler at a specific altitude the D...

Page 23: ...erious malfunctions Check again to ensure that no cables or any other parts are in the way before you proceed 4 2 Measuring the Inlet Gas Pressure WARNING The boiler cannot function properly without s...

Page 24: ...rt Reset the manometer to zero before use Digital pressure manometer 6 Re open the manual gas valve and check for leaks 7 Open multiple fixtures that have high flow rates such as bathtub and shower fa...

Page 25: ...2 230 2 080 1 950 1 840 1 630 3 11 300 7 780 6 250 5 350 4 740 4 290 3 950 3 670 3 450 3 260 2 890 4 23 100 15 900 12 700 10 900 9 660 8 760 8 050 7 490 7 030 6 640 5 890 in Cubic Feet ft3 per Hour 0...

Page 26: ...155 140 129 1 1 150 787 632 541 480 434 400 372 349 330 292 265 243 1 1 4 2 350 1 620 1 300 1 110 985 892 821 763 716 677 600 543 500 1 1 2 3 520 2 420 1 940 1 660 1 480 1 340 1 230 1 140 1 070 1 010...

Page 27: ...ath The qualified service agency is responsible for the proper installation of this kit The installation is not proper and complete until the operation of the converted appliance is checked as specifi...

Page 28: ...e screws are removed carefully separate the pipe from the gas valve 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...

Page 29: ...ews that hold the part in place Remove the Gas Orifice from its housing and prepare the new Gas Orifice for the LP conversion for installation Remove two 2 screws here Figure 4 Access to Gas Orifice i...

Page 30: ...o the boiler and tighten the three screws 15 Check the labels carefully and then connect all the wires 16 Set the front panel Dip Switch to change the gas type For LP set Dip Switch 2 2 to On For NG s...

Page 31: ...NAC 500 NG 0 04 in 0 01 in NAC 05 LP 0 02 in 0 01 in NCB 240E NAC 600 NG 0 04 in 0 01 in NAC 06 LP 0 02 in 0 01 in Table 3 Offset value for low fire Model Fuel High fire Low fire CO2 CO2 NCB 150E NG...

Page 32: ...al property damage 19 Once the CO2 or offset values have been confirmed apply the included conversion stickers to show that the appliance has been converted to propane gas Place these labels adjacent...

Page 33: ...ation Refer to the following table for detailed information a Space heating mode f S Supply water control Indicates space heating mode operation Indicates supply water control status b Error g R Retur...

Page 34: ...space heating and DHW supply temperatures Refer to the following table for detailed information k Diagnostics button n Up button For installers only Increases the temperature l MODE Mode button O Down...

Page 35: ...ey 5 seconds Individual deletion of Error History Tech Data Works only at the relevant mode Diagnostic long key 5 seconds Advancement into Test Menu Must be in normal mode 1 Parameter Setting 2 Error...

Page 36: ...y when a Level 1 error occurs will convert the Boiler to Level 1 Error Display mode Level 1 Error Display mode displays the error code and returns to Normal Operating mode after 5 seconds When the err...

Page 37: ...f 5sec 5 Cascade Slave Error display Slave Error code display NR NP cascade mode only Ex Slave unit No 10 Error 03 Item Description Display method 1 Normal status Normal Operating mode with power On W...

Page 38: ...er terminating the current mode 3 The Error icon and error code flash alternately at 1 second intervals at Error Display mode 4 The error code displays 3 digits 5 Entering Service Info Error History o...

Page 39: ...TE Take note of the original heating temperature in case you want to restore it to the default The default space heating supply water temperature range is 104 F 40 C Absolute MIN to 180 F 82 C Absolut...

Page 40: ...g water temperature For Celsius C mode ex at 60 C For Fahrenheit F mode ex 120 F B Space heating return water temperature Display of the current space heating incoming water temperature For Celsius C...

Page 41: ...5 C Outdoor Temperature display for Fahrenheit F mode with optional sensor ex at 59 F G Outdoor reset curve Display of heat load 1 7 If Finned Tube Baseboard is set 1 Finned Tube Baseboard 2 FAN Coil...

Page 42: ...rence history display 1 At the Normal operation mode or Error display mode press the Info button for over 2 seconds to access the error history mode The most recent error will be displayed first 2 Whe...

Page 43: ...hour then it automatically returns to the Normal operation mode Item Description Display A Space heating supply water temperature Display of the current space heating outgoing water temperature For Ce...

Page 44: ...sensor ex at 15 C Outdoor Temperature display for Fahrenheit F mode with optional sensor ex at 59 F G Outdoor reset curve Display of heat load 1 7 If Finned Tube Baseboard is set 1 Finned Tube Basebo...

Page 45: ...the flame by flame detection AD value 0 255 ex 200 L Target RPM Target fan motor RPM display Displays RPM deleting the 1st digit ex 3600rpm M Current RPM Current fan motor RPM display Display of RPM...

Page 46: ...ay for Fahrenheit F mode with sensor ex 120 F Exhaust Gas Temperature display without sensor Q Model and Capacity Currently set model and capacity display The 2nd 3rd digits represent the model and th...

Page 47: ...setting 0 2 000ft 2 000 5 400ft 5 400 7 700ft 7 700 10 100ft T Current units in cascade system Display of current number of cascade unit CASCADE OFF CASCADE ON U Cascade Operation Information Display...

Page 48: ...ed to test the operation condition of the boiler 3 Press the MODE Button once enters boiler to the currently displayed mode 4 Press the RESET button once returns the boiler to the Normal Operating Mod...

Page 49: ...Outdoor Reset Heat Load Setting This mode is used to configure the heat load type to be used with the Outdoor Reset Control mode A preset or user defined temperature range is selected automatically ba...

Page 50: ...supply or return set point range at this outdoor temperature Outdoor Low Temperature Setting Range Setting range Default Outdoor Low Temperature Set point 9 F 5 C 104 F 40 C 70 F 21 C For Celsius C mo...

Page 51: ...emperatures return to within the set ranges Setting range Default 0 20 minutes 3 minutes If Anti Fast Cycling Time set is 3 minutes I CH Pump Over run Time The pump overrun time is the duration that t...

Page 52: ...used to make changes to the maximum supply temperature range when the Supply Control mode is in use When configuring the Custom mode in the Outdoor Reset Control mode the supply temperature changes b...

Page 53: ...F 20 C MAX Set point 18 F 10 C 86 F 30 C For Celsius C mode ex at 30 C For Fahrenheit F mode ex at 86 F R AWS Operation Pressure setting This menu may be used to allow the boiler to maintain the spac...

Page 54: ...e Controller Communication This menu may be used to allow the boiler to work with a zone controller Setting range Default ON OFF OFF NPE Protocol setting Use Zone controller ON NPE Protocol setting Do...

Page 55: ...e boiler is not operating stop flow 3 Increase decrease and change the component check menu item with the button 4 For an item not supported by the current model do not display the item but skip it De...

Page 56: ...status 3 Way Valve 3 Way Valve will be turned On upon entering Test mode and pressing the button each time converts the state from On Off or Off On Whenever the button is pressed the condition is togg...

Page 57: ...s pressed once then it returns to the Special Parameter mode Displayed as the previously entered item 3 OPR 4 If there is no button input for 3 hours then it automatically returns to the Normal Operat...

Page 58: ...l the slave units are NPE water heaters b NR NP Use this setting when the slave units consist of NR NP water heaters or a combination of NPE and NR NP water heaters 4 4 12 Resetting the Boiler Factory...

Page 59: ...cedure To configure the cascade communication settings 1 On the master NCB E boiler press and hold the Diagnostic and Up buttons for more than 5 seconds MA 00 will appear on the display to confirm tha...

Page 60: ...swer for 60 seconds but the system operates normal communications once The error code will be displayed first on the Panel Controller regardless of error level when a Panel Communications Error occurs...

Page 61: ...elay 4 Relay 5 Communication Interface UART Communication Interface Ready Link Interface Air Handler FRONT PANEL Ready Link Output MCU 2 Flow Sensor APS Fan Hall Sensor DHW Inlet Thermistor 1 DHW Outl...

Page 62: ...nel BK BKBK BKBK BKBK BKBK BK CN13 B B Inlet1 Thermistor B B B B Outlet2 Thermistor B B B B Inlet2 Thermistor B B B B Outlet1 Thermistor B B B B Exhaust Thermistor B B BK BK High Limit S W CN1 BK R B...

Page 63: ...Pulse D Water Pressure Sensor CN22 1 2 RED BLACK DC 0 5V Voltage changes according to the Water Pressure E APS CN6 1 2 RED BLACK DC 5V Confirm steady voltage CN6 1 4 WHITE BLACK DC 0 3 4 5V Voltage ch...

Page 64: ...7 184V Confirm steady voltage CN8 2 4 BLACK YELLOW DC 15V Confirm steady voltage CN8 3 4 BLACK ORANGE DC 0 7 5V Voltage changes relative to fan operation CN8 1 4 BLACK WHITE 0 6500rpm Check PULSE N Au...

Page 65: ...the unit Failure Event Malfunctioning PCB Effects A component may not operate within the unit and could produce an error code In most cases of PCB failure the whole unit will not operate until the pro...

Page 66: ...F or 110 C in heat exchanger will activate the high limit switch Failure Event Unable to detect excessively high water temperature if switch fails Effects Unable to shut down the boiler if the water...

Page 67: ...07 E421 Diagnostic 1 Visual inspection Check wire connections are secure 2 Check the resistance of the sensor Stop operating and lower the temperature before checking Color Number of wires Resistance...

Page 68: ...bly screw is loose and or the fan is disassembled 3 Disconnected or defective fan connection terminal assembly Effects 1 Unstable combustion condition 2 Unit vibrating and noise 3 The boiler is not op...

Page 69: ...gnite during the ignition process 2 Produces multiple unsuccessful attempts to ignite Effects 1 The unit cannot ignite during the ignition process and E003 or E004 error codes will display 2 Durabilit...

Page 70: ...multiple unsuccessful attempts to ignite Effects 1 The unit cannot ignite during the ignition process and E003 or E004 error codes will display 2 Durability of the igniter wears down Error Code E003 E...

Page 71: ...e Effects 1 The boiler is not operating 2 Produces excessive carbon monoxide emissions Error Code E110 Diagnostic 1 Visual inspection Check wire connections are secure 2 Voltage check Check range of v...

Page 72: ...e situations Failure Event Unable to open close Effects 1 No flames 2 No operation of the unit Error Code E003 E012 Diagnostic 1 Visual inspection Check wire connections are secure 2 Check if the sole...

Page 73: ...1 Unable to initialize sustain combustion 2 Dust or soot deposit on the burner surface 3 Possible gas leakage from burners Effects 1 Abnormal combustion 2 Unstable flame conditions and or flame loss...

Page 74: ...e 2 Damage to and or water leakage from the water flow sensor Effects 1 Ignition sequence does not start 2 Stop operating once detecting water leakage Error Code E439 Diagnostic 1 Visual inspection Co...

Page 75: ...imizes the heat loss Failure Event 1 Water and or exhaust gas leakage through a crack 2 Improper heat transfer can cause the water in the heat exchanger to boil due to possible scale formation Effects...

Page 76: ...hamber which minimizes heat loss Failure Event 1 Water and or exhaust gas leakage through a crack 2 Improper heat transfer can cause the water in heat exchanger to boil Effects 1 Exhaust gas leakage 2...

Page 77: ...available Failure Event 1 Water leakage through a crack 2 Improper heat transfer can cause the cold water in heat exchanger Effects Temperature fluctuations in the hot water outlet and or leaking Erro...

Page 78: ...or measure water flow rate when the pump is called to operate Effects 1 The boiler freezes 2 Temperature fluctuations when the boiler is set to internal recirculation 3 Hot water is not quickly availa...

Page 79: ...omestic hot water in DHW mode Effects In the case that the temperature of space heating is lower than the set temperature it blocks the water flow path for domestic hot water so that heating water can...

Page 80: ...n heating Failure Event Unable to detect or measure to change water pressure Effects Water filling system does not operate automatically Error Code E351 E352 E353 Diagnostic 1 Visual inspection Check...

Page 81: ...ure Event 1 Water filling system does not operate automatically 2 Water filling system operates continuously Effects 1 System is low water pressure 2 If system is high water pressure for automatic fil...

Page 82: ...trol the amount of mixed gas by stage 1 and 2 Failure Event 1 Blade not closing 2 Blade not opening Effects 1 Frequent On Off due to excessive heat 2 Fail to reach the set temperature due to lack of h...

Page 83: ...ESET Abnormal APS open short initial value or no answer No error display CH System E205 2 Abnormal H E outlet thermistor open or short Auto RESET E218 1 Abnormal H E inlet thermistor open or short Ala...

Page 84: ...connection screws on heat exchanger E016 0 Overheating of heat exchanger Clean the inlet water filter and Strainer Check High Limit Switch Check for proper dipswitch settings see page 20 Check the 3 w...

Page 85: ...nlet2 thermistor Open Check the auto feeder valve Check incoming water pressure and any activity at PRV E353 1 Abnormal water pressure sensor Open Check the water pressure sensor 2 Abnormal water pres...

Page 86: ...that the outdoor reset curve is configured properly 2 Check the outdoor temperature sensor wiring connection 2 Abnormal outdoor temperature sensor Short appears only when the outdoor reset curve is e...

Page 87: ...ulation pump operating status 2 Check the 3 way valve operating status 3 Check if the heating strainer is clogged 4 Check if the main heat exchanger or the DHW heat exchanger is clogged 5 Check the he...

Page 88: ...water 3 Defective 3 way valve if power is normally supplied 4 Defective PCB if power is not supplied The heating strainer is clogged 1 Check if the strainer is clogged with debris 2 Check the cause o...

Page 89: ...ing Sudden increase of temperature due to PCB DIP S W model setting error or max setting Capacity DIP S W No 5 6 150 000 BTU 180 OFF OFF 175 000 BTU 210 ON OFF 199 000 BTU 240 OFF ON 120 000 BTU 150 O...

Page 90: ...rt circuit solenoid valve 5 Check the flame rod wiring and grounding 6 Check if the air pressure hose is broken or clogged 7 Check if the air pressure sensor works properly 8 Check the PCB DIP switch...

Page 91: ...gnition Failure Normal gas pressure 8 0 13 5 w c NO NO NO Yes Yes Yes Is gas valve operating normally Does the main gas valve have proper voltage Is gas valve open Scenario3 Access the Service Informa...

Page 92: ...MAX combustion setting DIP S W 1 1 ON 5 If a CSST connector has been used check to ensure that it is not been overtightened resulting in the seal obstructing gas flow 6 Check the meter class Example...

Page 93: ...e gap if there is a discharge of electricity from the metallic part of the burner Ensure that the insulating gasket is installed between the electrode and burner casing Check the input power to the ig...

Page 94: ...WHITE RED wires to verify that the input power is DC 22 24V 2 Replace the PCB if power is not supplied 3 If power supply is normal check if the coil is open Check the resistance refer to page 18 4 Ch...

Page 95: ...connection remove and reattach the ground wire ensuring good contact with the case Or use a multi meter to measure the flame sensing current normally 3 4 A Measuring flame current Grounding wire posit...

Page 96: ...ombustion stand by pre purge pre ignition a false flame error 004E automatically cleared is displayed on the front panel and the system performs continuous post purge and operates the pump 2 Post purg...

Page 97: ...trode to flame sensor at ignition Replace or correct location of flame detecting rod Gas valve Gas may leak as the main gas valve is pushed by the gas supply over the standard pressure Check the suppl...

Page 98: ...e front panel Check items 1 Measure with a manometer the gas supply pressure NG 3 5 10 5 W C LP 8 13 5 W C 2 Check the Gas meter Capacity 3 Tighten the ground connection screws on heat exchanger 4 Che...

Page 99: ...ctor If a CSST connector has been used check to ensure that it is not been over tightened resulting in the seal obstructing gas flow 6 Check the gas meter capacity Example Gas meter Boiler Furnace Dom...

Page 100: ...r replace it Flame loss and noise occurs after ignition PCB DIP switch setting error Check the PCB DIP switch settings Refer to page 18 1 2 3 4 5 6 7 8 9 10 1 2 ON ON 2 ON NG LP 2 ON Offset pressure a...

Page 101: ...04 in 0 01 in LP 0 03 in 0 01 in NCB 210E NG 0 04 in 0 01 in LP 0 02 in 0 01 in NCB 240E NG 0 04 in 0 01 in LP 0 02 in 0 01 in Offset value for low fire Flame loss during 2nd stage Blockage in the ga...

Page 102: ...heck items 1 Check if the overheat controller is working properly Check resistance value or continuity refer to page 65 2 Check the hot water temperature sensor refer to page 65 3 Check for proper pow...

Page 103: ...defective sensor check if the deviation of temperature is large due to a defective temperature sensor Check the output temperature displayed on the front panel 2 Measure the temperature sensor resist...

Page 104: ...230 F 110 C for 10 minutes or over E030 error code will display and perform post purge Automatically cleared 2 When the controller detects the exceeding temperature of 140 F 60 C while performing post...

Page 105: ...exchanger if it is damaged or cannot be unclogged Defective part Defective overheat controller Defective contact point of the exhaust gas overheat controller 230 F 110 C Max Check connection of the ov...

Page 106: ...thermistor Check connector 3 and 4 of CN 13 1 step Flushing Clean Filter 2 step Try to restart 3 step Replace PCB Yes Yes No No 5 2 8 047Error Error occurrence conditions and check items Is exhaust th...

Page 107: ...Dual Venturi is operating correctly Run the Dual Venturi Test Mode 2 Check that the wiring harness is connected correctly and the cables are not damaged Is Dual venturi closed Is Dual venturi repeate...

Page 108: ...until Fan Auto Adjusting is complete 4 Enter the Dual Venturi Test Mode and perform a test 1 Repeat the test at least twice Turning the unit ON and OFF once makes one test cycle ON OFF ON OFF is the m...

Page 109: ...nsor should be normal Check items 1 Check if the fan motor works normally using the component test mode refer to page 18 2 Check the power supply to the fan Black Red approx DC 127 184 V 3 If RPM is s...

Page 110: ...ng and the power supply is normal Follow the instructions listed below and replace the fan 1 Unplug the power cable to the unit and then wait for 10 seconds until the remaining SMPS voltage completely...

Page 111: ...ogged 2 Check if the condensation drain line or the drain is clogged 3 Check the flue and exhaust to verify proper installation and clearances Circulation of exhaust gas generates noise 4 Check if the...

Page 112: ...d 2 Replace the old PCB with the latest version Condensate drain error Condensate drain error Exhaust air is blocked due to condensate drain error Check if the condensate hose or the siphon is frozen...

Page 113: ...eason including leakage 2 Replace the defected heat exchanger output temperature sensor 3 Check circulation pump operating status and for proper flow through the space heating line 4 Check the voltage...

Page 114: ...e sensor Defective if it is 30k or higher Replace the temperature sensor if the resistance value is abnormal Check the temperature displayed on the front panel Possible Issues Defective circulation pu...

Page 115: ...e boiler initiates shutdown Check items 1 Check if the heat exchanger input temperature sensor connector is wet due to any reason including leakage 2 Replace the defected heat exchanger input temperat...

Page 116: ...istance of the temperature sensor Defective if it is 30k or higher Replace the temperature sensor if the resistance value is abnormal refer to page 66 Check the temperature displayed on the front pane...

Page 117: ...not refilled Check if the cold water valve is closed or frozen Check if the auto feeder valve works normally 2 Water overflows through condensed water hose Check the left drain valve of the main heat...

Page 118: ...feeder valve if power is supplied normally 3 Replace the PCB if power is not supplied Check if the filter is clogged with debris Water flow over through the condensed water hose Drain valve open Chec...

Page 119: ...ding leakage 2 Check the Auto Feeder Sensor 3 Check the controller Leaking in unit Is the water pressure sensor normal 1 Check connecter 1 2 and 3 of CN 22 Check leaking in unit Replace the water pres...

Page 120: ...he cold water pipe input water pressure sensor is wet due to any reason including leakage 2 Replace the water pressure sensor 3 Check the controller Leaking in unit Is the water pressure sensor normal...

Page 121: ...nt panel Check items 1 Check if the hot water temperature sensor connector is wet due to any reason and if the connector is connected properly 2 Check if the temperature sensor is open or short Is the...

Page 122: ...ge 18 Check the temperature displayed on the front panel refer to page 18 Possible Issues Defective PCB If the issues continue despite checking the items above replace the PCB DHW outlet elbow input t...

Page 123: ...the front panel Check items 1 Check if the cold water temperature sensor connector is wet due to any reason and if the connector is connected properly 2 Check if the temperature sensor is open or shor...

Page 124: ...istance of the temperature sensor Defective if it is 30k or higher Replace the temperature sensor if the resistance value is abnormal refer to page 18 Check the temperature displayed on the front pane...

Page 125: ...ches the unit operation into the Lock Out mode gas valve and ignition transformer locked Check items 1 Check the supply of cold water while the cascade system is disabled frozen locked valve 2 Defecti...

Page 126: ...the operating voltage is normal Other trouble Defective PCB If the issue continues despite the checking of items above the PCB is defective Emergency measures for a defective flow sensor Replacement o...

Page 127: ...id valve Refer to page 71 Check the Fan voltage 1 Check the wire connection between dual venturi and Main controller 2 Check the dual venturi 1 Turn off and on the Power RESET switch 2 In that same ca...

Page 128: ...he PCB Error occurrence conditions and check items Fault Possible Causes Check method E594 Error Abnormal communication by PCB 1 Click the Reset button on Front panel 2 Turn the POWER to the unit OFF...

Page 129: ...m displays the error message E740 on the front panel If this occurs the boiler changes the control mode from Reset Curve Mode to Normal Mode Check items 1 Check the parameter setting refer to page 18...

Page 130: ...being supplied to the LWCO Replace the main PCB Check LWCO Check the factory installed jumper and jumper connection CN24 Check the connecting terminals CN25 No No Yes No Yes Yes Yes Check method Fault...

Page 131: ...2 26 782Error Error occurrence conditions and check items Reconnect panel to the PCB 1 step Reset the unit 2 step If problem persists replace the PCB and Front panel Yes Is the wiring from the front...

Page 132: ...noise occurs at standard value adjust setting above below the standard 2 Gas supply error due to defective air pressure sensor 3 If the same error is repeated it is due to a defective PCB Noise durin...

Page 133: ...by the boiler The cold water temperature sensor may not work be working properly Low hot water temperature Hot water setting error Check the hot water temperature setting on the front panel Water mixe...

Page 134: ...Check if the wire is fixed and properly attached on the main side of the heat exchanger Normal assembly Short circuit due to defective assembly Wiring near the heat exchanger Circuit breaker operates...

Page 135: ...soap bubble solution Bubbles indicate a gas leak that must be corrected 7 Check the performance and operation after the boiler has been serviced To remove and replace any parts from the boiler you wi...

Page 136: ...all wiring connectors to the PCB 9 Set the proper DIP S W settings on the PCB refer to page 131 10 Reinstall the PCB and Front Panel using the 7 screws previously removed 11 Turn on the water and gas...

Page 137: ...e four screws from the bottom of the fan assembly Figure 6 9 Detach the fan motor from the assembly and replace it with the new part 10 Replace the 4 screws used to attach the fan motor to the assembl...

Page 138: ...re 12 6 2 5 IgnitionTransformer 1 Turn off the gas supply to the unit 2 Disconnect the unit from the power supply 3 Turn off the water supply to the unit 4 Remove the Ignition Transformer insulated ca...

Page 139: ...sure sensor 8 Replace the old air pressure sensor with the new part 9 Reattach the air pressure sensor hose 10 Connect the air pressure sensor wiring connector 11 Place the front panel back onto the u...

Page 140: ...pull off the hose 8 Remove the old condensation trap and replace it with the new part 9 Reconnect the hose to the condensate trap 10 Reattach the condensation trap to the unit and secure it using the...

Page 141: ...on water supply power supply and gas supply to the unit 13 Carefully open a hot water tap and ensure there are no leaks at the flow sensor connections 12 Turn on the water supply power supply and gas...

Page 142: ...position and ensure that all connections are tightly sealed 6 2 10 Circulation Pump 1 Turn off the gas supply to the unit 2 Disconnect the unit from the power supply 3 Turn off the water supply to the...

Page 143: ...s on the 3 way valve Figure 30 6 Remove the two screws on the bottom of case Figure 31 10 Secure the pump with the stainless steel clip and the 2 fixing screws Figure 28 Figure 29 11 Reinstall the pum...

Page 144: ...Drain all water from the appliance 4 Disconnect the water pressure sensor wire housing Figure 32 5 Pull out the water pressure sensor 6 Replace with new water pressure sensor 7 Connect the water pres...

Page 145: ...er supply to the unit 3 Turn off the water supply to the unit Drain all water from the appliance 4 Remove the siphon 5 Disconnect the wiring connector fastener and remove the stainless nut from the Au...

Page 146: ...08662B 2 Exhaust Pipe Assembly 30008673A 3 Case 20027375A NCB Models 20033278A NCB E Models 4 Intake Air Filter 20007667A NCB Models 5 Air Pressure Sensor 30010238A NCB Models 30010346A NCB E Models 6...

Page 147: ...Version 1 4 146 NCB E Service Manual 7 2 Burner Assembly 1 2 9 10 11 12 13 14 21 18 17 4 20 13 19 12 10 16 15 3 6 5 7 8...

Page 148: ...stor Exhaust 30009478A 10 Thermistor Water 30008366A 11 High Limit Switch 30002558A 12 Fastener 20007859A 13 O Ring P19 20017211A 14 Heat Exchanger Outlet Pipe 30014733A NCB 150E 30011913A NCB 180 201...

Page 149: ...3 6 28 3 16 2 36 21 32 3 33 30 24 23 19 19 27 26 37 26 25 30 29 6 34 13 22 21 3 20 16 35 31 35 16 18 3 2 1 3 22 24 28 16 35 27 35 16 26 Before 2015 5 15 prduced units only 38 Description Part Remark...

Page 150: ...0A 22 Connection Adaptor 20011408A 23 3 Way Valve 30004831B 24 Fastener 20007733B 25 Water Fill Pipe 30012247A 26 Space Heating Supply Adaptor A 20026931A NCB Models 2015 5 15 20033691A NCB Models 201...

Page 151: ...16 2 36 21 32 3 33 30 24 23 19 19 27 26 37 19 25 29 6 13 22 21 3 20 16 35 31 35 16 18 3 2 1 3 22 Description Part Remark 1 DHW Heat Exchanger 30015581A NCB 150E 30008181A NCB 180E 30005017A NCB 210E...

Page 152: ...r A 30012331A 21 Packing 20011380A 22 Connection Adaptor 20011408A 23 3 Way Valve 30004831B 24 Fastener 20007733B 25 Water Fill Pipe 30012247A 26 Space Heating Supply Adaptor A 20033691A NCB E Models...

Page 153: ...Version 1 4 152 NCB E Service Manual 7 5 Fan Gas Assembly 2 4 7 5 6 11 14 12 11 10 9 13 11 15 1 3 8...

Page 154: ...nce Adaptor 20033736A NCB 150 20023861A NCB 180 20019141A NCB 210 240 7 Venturi Packing 20022660A NCB 180 8 Gas Orifice 20033737A NCB 150 20024159A NCB 180 NG 20019144B NCB 210 240 NG 20034176A NCB 15...

Page 155: ...ng the Return Filter YES NO Checking the Intake Air Filter YES NO Flushing the Heat Exchanger YES NO Replacement of Parts 8 3 Maintenance Schedules Owner maintenance Daily Check boiler area Check pres...

Page 156: ...Memo...

Page 157: ...Memo...

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