Service Manual NRC83 (-DV, -OD) NRC98 (-DV, -OD) NRC1111/NCC1991(-DV,-OD) NR981/NC1991(-DVC,-OD,-SV) NR83-DVC. Rev: October, 2012.

Transcription

1 NC8 (-DV, -OD) NC98 (-DV, -OD) NC/NCC99(-DV,-OD) N98/NC99(-DVC,-OD,-SV) N8-DVC Service Manual efer to this manual whenever performing service or maintenance on this appliance. This manual will be used for service technician training seminars. The specifications and descriptions in this manual may be changed without prior notice. For further assistance, contact Noritz Technical Support at Do not short circuit any safety device on this appliance ITZ America Corporation Gas ater Heater ev: October, 0 Contents Important Safety Information.... Features.... Specifications/Performance Table.... Dimensions.... Components.... Operating Principle.... Operation Flow Chart iring Diagram Troubleshooting... 0 Error Codes and Checkpoints...0 Circuit board checkpoints... Error Descriptions and How to eset... 8 emote Controller... Displaying Maintenance Monitors... Maintenance Monitor List... Circuit Board eplacement...7 hen Changing the Fan Motor...7 Gas Line equirements...7 Manifold Gas Pressure Adjustment... 7 Periodic lnspection...78 Periodic Maintenance Changing Default Temperature Setting Installation Check...8 KS--000

2 Important Safety Information To prevent damage to property and injury to the user, the icons below warn of varying levels of risk. Ignoring this indication will cause an immediate danger of death or arning serious injury. Caution Ignoring this indication may result in death or serious injury. Prohibited.. Safety Tips for Service ear the appropriate clothing and protective gear: Caution In order to prevent injury or accident, wear a protective helmet, safety boots and a lifting belt whenever necessary. Use only the appropriate tools and parts: Only use replacement parts manufactured by Noritz for this model as listed in the arning Installation Manual Parts List for service on this unit. Use appropriate tools. Modi cation of the unit is prohibited: Do not attempt to modify or alter the unit. This will cause a re hazard and a risk of electrical shock. hen servicing: arning Disconnect the power supply during maintenance and repairs to reduce the risk of electric shock. If it is necessary to have the electricity connected during repairs, use extreme caution not to touch parts that may cause a shock. Do not short circuit any safety device on this appliance: If a safety device is not functioning properly, replace the part. Do not under any circumstances short circuit the part. Exhaust and gas leakage caution: Always check for leaks when installing or modifying the exhaust vent or gas piping. arning. Post-Service Checks Check parts for leaks: Confirm that t h e r e a r e n o g a s, w a t e r, o r e x h a u s t l e a k s r e g a r d l e s s o f w h e t h e r t h e Caution service performed could have caused them. If the unit is installed indoors, check that the flue collar and vent pipe are installed correctly and that they are in good condition. Confirm that there are no gas, water or exhaust leaks regardless of whether the service performed could have caused them. Check for combustibles: Caution Check insulation resistance: After service or maintenance is completed, check that there are no combustibles in the vicinity of the unit. After service or maintenance is completed, measure the resistance between the arning electrical wires and ground. If it is less than 0MΩ, there is a risk of electrical shock. Properly reconnect the power supply: Confirm that the power supply has been reconnected properly after service or arning maintenance is completed. Also confirm that there is no dust or other obstacles that might cause an electric shock or a fire hazard.

3 . Features. Quick Connect Multi System Allows the simple installation of up to units linked together using a Quick Connect Cord CCP Valve System controller Not required. Maximum emote Controller Length (Only one remote controller can be connected.) emote controller ( unit): Cord can be extended up to 00' with 8AG wire. * Note: In a Quick Connect Multi-System, only one remote controller will be installed.. Temperature Lockout Function The remote controller can be set to restrict the maximum allowable temperature setting for added safety. See "Changing Default Temperature Setting" section for details.. Elevation Adjustment The water heater can be quickly configured for installations above 000' by simply adjusting dip switches inside of the unit. No additional equipment or adjustments are necessary. See the "Installation Manual" for details.

4 . Specifications/Performance Table Item Model Name Type Ignition Operating Pressure Minimum Flow ate Dimensions (Height) x (idth) x (Depth) eight ater Holding Capacity Connection Sizes Power Supply Materials NC98(-DV/-OD) Safety Devices Accessories Installation Air Supply/Exhaust ater Inlet Hot ater Outlet Gas Inlet Condensate Drain Supply Consumption Specifications Casing Flue Collar Primary Heat Exchanger Secondary Heat Exchanger Specification NC98-DV NC98-OD Indoor all Mounted Outdoor all Mounted Power Vented Direct Ignition -0 psi 0. GPM ( L/min.)." (mm) x 8." (mm) x 9." (0mm) 8 lbs. 7 lbs. 0. Gallon (.8L) /" / / / Threaded 0 VAC (0Hz) NG : 7 LP : 78 NG : LP : 8 Freeze Prevention Freeze Prevention 0 Zincified Steel Plate/Polyester Coating PVC Stainless Steel Copper Sheeting, Copper Tubing Stainless Steel Sheeting, Stainless Steel Tubing Flame od, Thermal Fuse, Lightning Protection Device (ZN), Overheat Prevention Device, Freezing Prevention Device, Fan otation Detector emote Controller, emote Controller Cord, Anchoring Screws Item Model Name Type Ignition Operating Pressure Minimum Flow ate Dimensions (Height) x (idth) x (Depth) eight ater Holding Capacity Connection Sizes Power Supply Materials Safety Devices Accessories NC8(-DV/-OD) Installation Air Supply/Exhaust ater Inlet Hot ater Outlet Gas Inlet Condensate Drain Supply Consumption Casing Flue Collar Primary Heat Exchanger Secondary Heat Exchanger Specification NC8-DV NC8-OD Indoor all Mounted Outdoor all Mounted Power Vented Direct Ignition -0 psi 0. GPM ( L/min.)." (mm) x 8." (mm) x 9." (0mm) 8 lbs. 7 lbs. 0. Gallon (.8L) /" / / / Threaded 0 VAC (0Hz) NG : 8 LP : NG : LP : Freeze Prevention Freeze Prevention 0 Zincified Steel Plate/Polyester Coating PVC Stainless Steel Copper Sheeting, Copper Tubing Stainless Steel Sheeting, Stainless Steel Tubing Flame od, Thermal Fuse, Lightning Protection Device (ZN), Overheat Prevention Device, Freezing Prevention Device, Fan otation Detector emote Controller, emote Controller Cord, Anchoring Screws

5 NC(-DV,-OD) / NCC99(-DV,-OD) Item Model Name Type Ignition Operating Pressure Minimum Flow ate Dimensions eight ater Holding Capacity Connection Sizes Power Supply Materials Safety Devices Accessories NC-DV NCC99-DV Installation Indoor, all Mounted Air Supply/Exhaust ater Inlet Hot ater Outlet Gas Inlet Supply Consumption Casing Flue Collar Heat Exchanger NC-OD NCC99-OD Outdoor, all Mounted Power Vented Direct Ignition -0 psi 0. GPM."(Height) x 8."(idth) x 9."(Depth) 8 lbs. lbs. 0. Gallon /" /" /" 0 VAC (0Hz) NG : 8 NG : 78 LP : 8 LP : 80 Freeze Prevention PVC Copper Sheeting, Copper Tubing Flame od, Thermal Fuse, Lightning Protection Device (ZN), Overheat Prevention Device, Freeze Prevention Device, Fan otation Detector Anchoring Screws N98 (-SV,-OD,-DVC) / NC99 (-OD,-DVC) Item Model Name Type Ignition Operating Pressure Minimum Flow ate Dimensions eight ater Holding Capacity Connection Sizes Power Supply Materials Safety Devices Accessories Installation Air Supply/Exhaust ater Inlet Hot ater Outlet Gas Inlet Supply Consumption Casing Flue Collar Heat Exchanger N98-OD NC99-OD Outdoor, all Mounted."(Height) x.8"(idth) x 9."(Depth) N98-SV Power Vented Direct Ignition -0 psi 0. GPM Indoor, all Mounted N98-DVC NC99-DVC."(Height) x.8"(idth) x.0"(depth) lbs. 8 lbs. 0. Gallon /" /" /" 0 VAC (0Hz) NG : NG : NG : 80 LP : 9 LP : 7 LP : 8 Freeze Prevention Freeze Prevention 9 Stainless Steel Copper Sheeting, Copper Tubing Flame od, Thermal Fuse, Lightning Protection Device (ZN), Overheat Prevention Device, Freeze Prevention Device, Fan otation Detector emote Controller, emote Controller Cord, Anchoring Screws Anchoring Screws

6 N8-DVC Item Model Name Type Ignition Operating Pressure Minimum Flow ate Dimensions (Height) x (idth) x (Depth) eight ater Holding Capacity Connection Sizes ater Inlet Hot ater Outlet Gas Inlet Power Supply Supply Consumption Materials Casing Flue Collar Heat Exchanger Safety Devices Accessories Installation Air Supply/Exhaust Specification N8-DVC Indoor all Mounted Power Vented Direct Ignition -0 psi 0. GPM ( L/min.)." (00mm) x.8" (0mm) x 9." (0mm) 9 lbs. 0. Gallon (0.9L) /" /" /" 0 VAC (0Hz) NG : 8 LP : 90 Freeze Prevention Zincified Steel Plate/Polyester Coating Stainless Steel Copper Sheeting, Copper Tubing Flame od, Thermal Fuse, Lightning Protection Device (ZN), Overheat Prevention Device, Freezing Prevention Device, Fan otation Detector Anchoring Screws

7 Performance Item Gas Consumption Maximum Hot ater Capacity Capacity ange Temperature Settings Default Temperature Options Maximum Performance Minimum Performance F ( C) ise F Mode: NC98-DV NG : 80,000 btuh NG :,000 btuh NC98-OD LP : 80,000 btuh LP :,000 btuh 7. GPM (8. L/min.) GPM (-7.0 L/min.) 00-0 F (In F intervals) (9 Options) C Mode: 7-8 C (In C intervals), 0,,0 C (In C intervals) ( Options) 0 F (0 C), 0 F ( C), 0 F (0 C) (Original is 0 F (0 C)) Item Gas Consumption Maximum Hot ater Capacity Capacity ange Temperature Settings Default Temperature Options Maximum Performance Minimum Performance F ( C) ise F Mode: NC8-DV NG : 7,000 btuh NG :,000 btuh NC8-OD LP : 7,000 btuh LP :,000 btuh. GPM (.0 L/min.) GPM (-. L/min.) 00-0 F (In F intervals) (9 Options) C Mode: 7-8 C (In C intervals), 0,,0 C (In C intervals) ( Options) 0 F (0 C), 0 F ( C), 0 F (0 C) (Original is 0 F (0 C)) Item NC-DV NC-OD NCC99-DV NCC99-OD Gas Consumption Maximum Hot ater Capacity F ise Capacity ange Maximum Performance Minimum Performance Default Temperature Options 0, 0, 0 F (Original is 0 F) 0, 0, 0, 8 F (Original is 0 F) Temperature Settings (Using the emote Controller) NG : 99,900 btuh LP : 99,900 btu NG :,000 btuh LP :,000 btuh 8. Gal./min Gal./min F (In F intervals), (9 Options) 00-0 F (In F intervals), 0, 70, 8 F ( Options) Item N98-DVC / N98-OD / N98-SV NC99-DVC NC99-OD Gas Consumption Maximum Performance NG : 99,900 btuh LP : 99,900 btu Minimum Performance NG :,000 btuh LP :,000 btuh Maximum Hot ater Capacity F ise Capacity ange 7. Gal./min Gal./min. Default Temperature Options 0, 0, 0 F (Original is 0 F) 0, 0, 0, 8 F (Original is 0 Temperature Settings (Using the emote Controller) 00-0 F (In F intervals), (9 Options) 00-0 F (In F intervals), 0, 70, 8 F ( Options) Item Gas Consumption Maximum Hot ater Capacity Capacity ange Temperature Settings Default Temperature Options Maximum Performance Minimum Performance F ( C) ise F Mode: C Mode: F Mode: C Mode: N8-DVC NG : 80,000 btuh LP : 80,000 btuh NG : 8,000 btuh LP : 8,000 btuh.7 GPM (. L/min.) GPM (-. L/min.) 00-0 F (In F intervals) (9 Options) 7-8 C (In C intervals), 0,,0 C (In C intervals) ( Options) 0,0,0 F (Original is 0 F) 0,,0 C (Original is 0 C) 7

8 Set temperature ( F) Hot ater Supply Capabillities < NC98 Series > [inter] Inlet water temp. F [Spring/Fall] Inlet water temp. F [Summer] Inlet water temp. 8 F Flow ate (GPM) < NC8 Series > Set temperature ( F) Flow ate (GPM) Flow ate (GPM) [inter] Inlet water temp. F [Spring/Fall] Inlet water temp. F [Summer] Inlet water temp. 8 F Set temperature ( F) Set temperature ( F) Flow ate (GPM) Set temperature ( F) Flow ate (GPM) Set temperature ( F) Flow ate (GPM) <NC-DV, NC-OD> Set temperature ( F) [inter] Inlet water temp. F Flow ate (GPM) Set temperature ( F) [Spring / Fall] Inlet water temp. F Flow ate (GPM) 9 0 Set temperature ( F) [Summer] Inlet water temp. 8 F Flow ate (GPM) 9 0 <NCC99-DV, NCC99-OD> [inter] Inlet water temp. F [Spring / Fall] Inlet water temp. F [Summer] Inlet water temp. 8 F Set temperature ( F) Flow ate (GPM) <NC99-OD, NC99-DVC> Set temperature ( F) Flow ate (GPM) 9 0 Set temperature ( F) Flow ate (GPM) 9 0 [inter] Inlet water temp. F Flow ate (GPM) [Spring / Fall] Inlet water temp. F Flow ate (GPM) [Summer] Inlet water temp. 8 F Flow ate (GPM) 8

9 Set temperature ( F) Hot ater Supply Capabillities <N98-OD, N98-DVC, N98-SV> [inter] Inlet water temp. F <N8-DVC> [Spring / Fall] Inlet water temp. F Flow ate (GPM) [Summer] Inlet water temp. 8 F Flow ate (GPM) [inter] Inlet water temp. F [Spring/Fall] Inlet water temp. F [Summer] Inlet water temp. 8 F Flow ate (GPM) Set temperature ( F) Flow ate (GPM) Set temperature ( F) Flow ate (GPM) < NC98 Series > Pressure Loss Characteristics <NC/NCC99> 0 Bypass Flow Control Valve Open Set temperature : 0F or less (Storage Tank Setting / System Controller : 0 F or less) 0 0 Pressure loss [psi] 0 0 Bypass Flow Control Valve Close Set temperature : F or higher (Storage Tank Setting / System Controller : 70-8 F) Pressure loss [Ft. of head] Flow rate [GPM] < NC8 Series > <N98/NC99> Bypass flow control valve Close Set temperature : F or higher storage Tank Setting / System Controller : 70-8 F) Bypass flow control valve Open Set temperature : 0 F or less (storage Tank Setting / System Controller : 0 F or less) Pressure Loss (Ft. of head) Flow ate (GPM)

10 Pressure Loss (psi) < N8-DVC> Flow ate (GPM) 0

11 . Dimensions NC98-DV NC8-DV 7.7" (0mm) < inch (mm)> -Ø0." (mm) - 0." x 0." (mm x 0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm) 0." (0mm)." (mm) 9." (0mm)." (0mm) Ø." (mm) Ø." (89.mm)." (8mm) AI INLET 8." (mm) 7." (8mm).9" (0mm) 9." (mm) Ø." (mm) Ø." (89.mm) FLUE COLLA HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET 0.9" (mm).8" (mm).9" (9mm)." (mm)." (mm)." (8mm)." (mm)." (8mm).9" (9mm).0" (0mm) (VIE FOM TOP)." (0mm) 7.0" (79mm)." (9mm)." (0mm)." (mm)." (mm)." (mm).8" (70mm).9" (00mm)." (0mm).7" (70mm) 0." (0mm) - 0." x 0." (mm x 0mm) OONG HOLE -Ø0." (mm) IING THOOUGHAY CONDENSATE DAIN ATE DAIN VALVE ATE DAIN VALVE (ATE FILTE) HOT ATE OUTLET ATE DAIN VALVE IING THOOUGHAY (AC0V) GAS INLET COLD ATE INLET HOT ATE OUTLET (/") CONDENSATE DAIN (/") IING THOOUGHAY." (mm)." (7mm) 9." (mm) GAS INLET (/") IING THOOUGHAY (AC0V) COLD ATE INLET (/") (VIE FOM TOP) NC98-OD NC8-OD 7.7" (0mm) < mm [inch] > - Ø0."(Ømm) - 0." x 0." ( x0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm) 0." (0mm) 9." (0mm) 0." (mm)." (8mm) FLUE COLLA 8." (mm) 7." (8mm) 0." (7mm).9" (99mm)." (mm) HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET 0.8" (0mm).8" (mm).9" (9mm)." (mm)." (mm)." (8mm)." (mm)." (mm)." (8mm).9" (9mm).0" (0mm) (VIE FOM TOP).0" (mm)." (0mm) 7.0" (79mm)." (9mm)." (mm)." (0mm)." (mm)." (mm) AI INLET AI INLET." (mm).8" (70mm).9" (00mm)." (0mm).7" (70mm) - 0." x 0." ( x0mm) OONG HOLE - Ø0."(Ømm) HEIGHT OF EACH FITTING 0." (0mm) IING THOOUGHAY CONDENSATE DAIN ATE DAIN VALVE ATE DAIN VALVE (ATE FILTE) HOT ATE OUTLET ATE DAIN VALVE IING THOOUGHAY GAS INLET IING THOOUGHAY (AC0V) COLD ATE INLET HOT ATE OUTLET(/") CONDENSATE DAIN(/") IING THOOUGHAY." (mm)." (7mm) 9." (mm) IING THOOUGHAY GAS INLET(/") IING THOOUGHAY (AC0V) COLD ATE INLET(/")

12 NCC99-DV 7.7" (0mm) < inch (mm) > - Ø0." (Ømm) - 0." x 0." ( x 0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm)." (mm) 0." (0mm) 9." (0mm)." (0mm)." (9mm) Ø." (Ømm) Ø." (Ø89mm) AI INLET 8." (8mm) 7." (8mm).9" (0mm) 9." (mm) Ø." (Ømm) Ø." (Ø89mm) FLUE COLLA HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET NCC99-DV 0.8" (0mm).7" (mm)." (mm)." (mm)." (mm)." (8mm)." (9mm) LED.9" (99mm).8" (70mm) (VIE FOM TOP) 0.0" (mm) 8." (mm) IING THOOUGHAY (AC0V).8" (7mm)." (mm).7" (7mm) 7.0" (77mm) - 0." x 0." ( x 0mm) OONG HOLE - Ø0." (Ømm)." (mm) 0." (0mm).8" (70mm).9" (00mm)." (0mm).7" (70mm) IING THOOUGHAY CONDENSATE DAIN ATE DAIN VALVE HOT ATE OUTLET ATE DAIN VALVE COLD ATE INLET ATE DAIN VALVE (ATE FILTE) GAS INLET ATE DAIN VALVE IING THOOUGHAY (AC0V)." (mm)." (09mm)." (0mm) HOT ATE OUTLET (/") CONDENSATE DAIN (/") IING THOOUGHAY.9" (98mm).7" (mm)." (mm) GAS INLET (/") COLD ATE INLET (/") NCC99-OD 7.7" (0mm) < inch (mm) > - Ø0." (Ømm) - 0." x 0." ( x 0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm) 0." (0mm) 9." (0mm) 0." (mm)." (9mm) FLUE COLLA 8." (8mm) 7." (8mm) 0." (7mm).0" (0mm)." (mm) HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET NCC99-OD 0.8" (0mm).7" (mm)." (mm)." (mm) (VIE FOM TOP)." (mm)." (8mm)." (9mm) LED." (mm).9" (99mm).8" (70mm) 0.0" (mm) 8." (mm) IING THOOUGHAY (AC0V).8" (7mm)." (mm).7" (7mm) 7.0" (77mm) AI INLET AI INLET." (mm).8" (70mm).9" (00mm)." (0mm).7" (70mm) 0." (0mm) - 0." x 0." ( x 0mm) OONG HOLE - Ø0." (Ømm) IING THOOUGHAYS CONDENSATE DAIN ATE DAIN VALVE HOT ATE OUTLET ATE DAIN VALVE COLD ATE INLET ATE DAIN VALVE (ATE FILTE) GAS INLET ATE DAIN VALVE IING THOOUGHA (AC0V)." (mm)." (09mm)." (0mm) HOT ATE OUTLET (/") CONDENSATE DAIN (/") IING THOOUGHAYS.9" (98mm).7" (mm)." (mm) GAS INLET (/") COLD ATE INLET (/")

13 NC-DV 7.7" (0mm) < inch (mm) > - Ø0." (Ømm) - 0." x 0." ( x 0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm) 0." (0mm) 9." (0mm)." (0mm)." (mm) Ø." (Ømm)." (8mm) Ø." (Ø89mm) AI INLET 8." (mm) 7." (8mm).9" (0mm) 9." (mm) Ø." (Ømm) Ø." (Ø89mm) FLUE COLLA HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET NC-DV 0.8" (0mm).7" (mm)." (mm)." (mm) (VIE FOM TOP)." (mm)." (8mm)." (mm).9" (99mm).8" (70mm) 8." (mm)." (mm).7" (7mm) 7.0" (77mm) - Ø0." (Ømm)." (mm) 0." (0mm).8" (70mm).9" (00mm)." (0mm).7" (70mm) - 0." x 0." ( x 0mm) OONG HOLE IING THOOUGHAY CONDENSATE DAIN ATE DAIN VALVE HOT ATE OUTLET ATE DAIN VALVE COLD ATE INLET IING THOOUGHA (AC0V) ATE DAIN VALVE (ATE FILTE) GAS INLET ATE DAIN VALVE." (mm)." (09mm)." (0mm) HOT ATE OUTLET (/") CONDENSATE DAIN (/") IING THOOUGHAY.9" (98mm).7" (mm)." (mm) GAS INLET (/") COLD ATE INLET (/") IING THOOUGHAY (AC0V) NC-OD 7.7" (0mm) < inch [mm] > - Ø0." (Ømm) - 0." x 0." ( x 0mm) OONG HOLE.7" (70mm)." (0mm).9" (00mm).8" (70mm)." (mm)." (0mm) 0." (0mm) 9." (0mm) 0." (mm)." (8mm)." (mm) FLUE COLLA 8." (mm) 7." (8mm) 0." (7mm).9" (99mm)." (mm) HEIGHT OF EACH FITTING FOM BOTTOM OF CASE CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET NC-OD 0.8" (0mm).7" (mm)." (mm)." (mm) (VIE FOM TOP)." (mm)." (8mm) AI INLET." (mm).0" (mm)." (mm) AI INLET.9" (99mm).8" (70mm) 0.0" (mm) 8." (mm) IING THOOUGHAY (AC0V).8" (7mm)." (mm).7" (7mm) 7.0" (77mm)." (mm) m ) 0 m ( ". 0 ) m m ( " 7.9". (8mm).8" (70mm).9" (00mm) IING THOOUGHAYS." (0mm) CONDENSATE DAIN.7" (70mm) ATE DAIN VALVE - 0." x 0." ( x 0mm) OONG HOLE - Ø0." (Ømm) HOT ATE OUTLET ATE DAIN VALVE COLD ATE INLET ATE DAIN VALVE (ATE FILTE) GAS INLET ATE DAIN VALVE IING THOOUGHA (AC0V)." (mm)." (09mm)." (0mm) HOT ATE OUTLET (/") CONDENSATE DAIN (/") IING THOOUGHAYS.9" (98mm).7" (mm)." (mm) GAS INLET (/") COLD ATE INLET (/")

14 N98-DVC NC99-DVC [."] HEIGHT OF EACH FITTINGS FOM BOTTOM OF CASE N98-DVC/NC99-DVC 0~[0."~.8"] 80[.0"] 0[.8"] % / * + / ( 0[."] 00[.9"] 70[.8"] [."] [.0"] [."] 0[.0"] 8[."] 7[.0"] 79[."] 0[.8"] [."] FLUE COLLA AI INLET CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET (VIE FOM TOP).8"[mm]."[mm]."[mm] - [ 0."] [."] [9."] [."] 7[."] 00[."] 8[7."] 79[."] [.9"] 99[7.8"] 0~[0."~.8"] 0[.0"] 8[."] :,, * 7+ 8 * + : $ < 0[.7"] (AC0V) % / * + / ( - [ 0."] + 7 : $ 7( 8 7/ ( 7 ATE DAIN VALVE * $, / ( 7 COLD ATE INLET ATE DAIN VALVE (ATE FILTE) + 7 : $ 7( 8 7/ ( 7 88[7."] [0."] & / ' : $ 7(, / ( 7 * $, / ( 7 :,, * 7+ 8 * + : $ < (AC0V) N98-OD NC99-OD [."] HEIGHT OF EACH FITTINGS FOM BOTTOM OF CASE - [ 0."] % / * + / ( 0[.7"] 8[."] 0[.0"] 0[0."] [."] 0[0."] 0[."] 8[."] 0[.7"] 7[."] [."] 0[0."] 0[9."] 0[0."] 8[."] 0[0."] % / * + / ( - [ 0."] AI INLET FLUE COLLA 00[."] :,, * 7+ 8 * + : $ < 0[.8"] [."] [9.9"] [."] 88[."] [.7"] AI INLET + 7 : $ 7( 8 7/ ( 7 :,, * 7+ 8 * + : $ < :,, * 7+ 8 * + : $ < (AC0V) ATE DAIN VALVE (ATE FILTE) * $, / ( : $ 7( 8 7/ ( 7 ATE DAIN VALVE COLD ATE INLET HOT ATE OUTLET COLD ATE INLET GAS INLET 0[."] [."] [."] [."] 0[.0"] + 7 : $ 7( 8 7/ ( 7 :,, * 7+ 8 * + : $ < [.7"] (VIE FOM TOP) [9."] [0."] N98-OD / NC99-OD.8"[mm]."[mm]."[mm] 97[.8"] 7[.7"] & / ' : $ 7(, / ( 7 * $, / ( 7 :,, * 7+ 8 * + : $ < (AC0V)

15 [."] N98-SV HEIGHT OF EACH FITTINGS FOM BOTTOM OF CASE N98-SV HOT ATE OUTLET.8"[mm] - [ 0."] -. [0. 0."]OONG HOLE 0[.7"] 8[."] 0[.0"] 0[0."] [."] 0[0."] 9[.7"] 0[9."] 8[."] 0[.8"] [."] 00[φ"] FLUE COLLA COLD ATE INLET 0[."] GAS INLET (VIE FOM TOP) [9."]."[mm]."[mm] [."] [."] 7[."] 70[.8"] 00[."] AI INLET [."] 0[.0"] 97[.8"] 7[.7"] HOT ATE OUTLET (/") COLD ATE INLET (/") 0[."] 8[."] 0[.7"] 0[0."] 0[0."] IING THOUGHAY IING THOUGHAY 88[7."] IING THOUGHAY (AC0V) IING THOUGHAY [0."] GAS INLET (/") IING THOUGHAY (AC0V) -..[0. 0."]OONG HOLE - [ 0."] ATE DAIN VALVE (ATE FILTE) GAS INLET HOT ATE OUTLET COLD ATE INLET ATE DAIN VALVE N8-DVC <inch(mm)>." (mm) 0." -.8" (0 - mm) 9." (0mm) HEIGHT OF EACH FITTINGS FOM BOTTOM OF CASE N8-DVC - 0." x 0." ( x0mm) OONG HOLE." (0mm).9" (00mm).8" 70mm)." (mm) - Ø0." (Ø mm)." (mm)." (7mm).0" (mm).8" (mm)." (mm).0" (0mm)." (8mm) Ø.0" (Ø7mm) Ø." (Ø79mm)." (00mm).8" (0mm)." (mm) FLUE COLLA AI INLET CONDENSATE DAIN HOT ATE OUTLET COLD ATE INLET GAS INLET.9" (0mm).0" (7mm) (VIE FOM TOP) 0.9" (77mm)." (mm).8" (mm).9" (9mm)." (mm)." (0mm).7" (7mm).0" (0mm)." (8mm).7" (0mm) - 0." x 0." (. xmm) OONG HOLE - Ø0." (Ø mm) 0." -.8" (0 - mm) IING THOUGHEAY (AC0V) HOT ATE OUTLET ATE DAIN VALVE GAS INLET COLD ATE INLET ATE DAIN VALVE (ATE FILTE) HOT ATE OUTLET (/")." (9mm) 8." (9mm) COLD ATE INLET (/") GAS INLET (/") IING THOUGHAY (AC0V)

16 . Components NC98-DV NC8-DV AI INLET FLUE COLLA Freeze Prevention Heater Heat Exchanger Thermistor Secondary Heat Exchanger Freeze Prevention Heater Igniter Freeze Prevention Heater High Limit Switch Freeze Prevention Heater Q Primary Heat Exchanger Thermal fuse Burner Drain cover Condensate Trap Manifold Fan Motor Main Flow Control Valve Lightning arrester ater Flow Sensor ater Drain Valve Hot ater Outlet ater Drain Valve ater Inlet Power supply cord Gas Inlet

17 NC98-OD NC8-OD FLUE COLLA Freeze Prevention Heater Secondary Heat Exchanger Freeze Prevention Heater Igniter Heat Exchanger Thermistor High Limit Switch Freeze Prevention Heater Q Primary Heat Exchanger Thermal fuse Burner Drain cover Condensate Trap Manifold Fan Motor Main Flow Control Valve Lightning arrester ater Flow Sensor Power supply cord ater Drain Valve Hot ater Outlet ater Drain Valve ater Inlet Power supply cord Gas Inlet Junction Box 7

18 NC-DV NCC99-DV 8

19 NC-OD NCC99-OD 9

20 N98-DVC NC99-DVC Flue Collar Air Inlet Igniter Freeze Prevention Heater Primary Heat Exchanger Heat Exchanger Thermistor Flame od High Limit Switch Freeze Prevention Heater Ignition Plug Thermal Fuse Burner Manifold Fan Motor Bypass Flow Control Valve Freeze Prevention Heater Main Flow Control Valve ater Outlet Thermistor Freeze Prevention Heater Circuit Board Freeze Prevention Heater Lightning Arrester ater Inlet Thermistor ater Flow Sensor Freeze Prevention Heater Hot ater Outlet ater Drain Valve ater Drain Valve (ater Filter) Gas Inlet ater Inlet Air Inlet Thermistor iring Thoroughways 0

21 N98-OD NC99-OD Igniter Exhaust Flue Heat Exchanger Thermistor Freeze Prevention Heater High Limit Switch Primary Heat Exchanger Ignition Plug Flame od Thermal Fuse Burner Fan Motor Bypass Flow Control Valve Freeze Prevention Heater Main Flow Control Valve ater Outlet Thermistor Freeze Prevention Heater Manifold Circuit Board Freeze Prevention Heater Lightning Arrester ater Inlet Thermistor ater Flow Sensor Freeze Prevention Heater Hot ater Outlet emote Controller Terminal Block iring Thoroughways ater Drain Valve Junction Box ater Drain Valve (ater Filter) Gas Inlet ater Inlet Air Inlet Thermistor

22 N98-SV Exhaust Flue Igniter Freeze Prevention Heater Heat Exchanger Thermistor Flame od Primary Heat Exchanger High Limit Switch Freeze Prevention Heater Ignition Plug Thermal Fuse Burner Manifold Fan Motor Bypass Flow Control Valve Freeze Prevention Heater Main Flow Control Valve ater Outlet Thermistor Freeze Prevention Heater Circuit Board Freeze Prevention Heater Lightning Arrester ater Inlet Thermistor ater Flow Sensor Freeze Prevention Heater Hot ater Outlet emote Controller Terminal Block iring Thoroughways ater Drain Valve ater Drain Valve (ater Filter) Gas Inlet ater Inlet Air Inlet Thermistor iring Thoroughways

23 N8-DVC Flue Collar Air Inlet Igniter Heat Exchanger Thermistor Freeze Prevention Heater High Limit Switch Heat Exchanger Manifold Fan Motor Freeze Prevention Heater Lightning arrester Main Flow Control Valve Freeze Prevention Heater Power supply cord ater Flow Sensor ater Inlet Hot ater Outlet ater Drain Valve Freeze Prevention Heater Freeze Prevention Heater Gas Inlet

24 emote controller (C-7M) Burner On Indicator hen burning, the indicator is lit. Priority Indicator hen this indicator is lit, the hot water temperature can be set. Temperature Setting (Ex.:0 F) Flow Meter Setting The display will flash after hitting the flow meter alarm set button. Setting Buttons For setting the hot water temperature, the flow meter alarm, and other settings. Power On/Off Button For turning the heater on and off. Flow Meter Alarm Set Button For setting the flow meter alarm. Error Code A number will flash if a failure occurs. * Before use, remove the protective sheet from the operation panel surface. Note: As shipped from the factory, the remote controller is set to display in F and gallons. To adjust the display to C and liters, refer to the "emote Controller" section for details. emote controller (C-908M) The remote controller will emit a tone when a button is pressed. Prog Button / Indicator (ed) Activates the automatic water heater power ON or OFF setting as determined by the user selected schedule. PowerON/OFF Button / Indicator (Green) For turning the water heater on/off. Menu Button * Use to change system settings or to return to the home screen. * If you press the menu button and press the temperature setting buttons, is sometimes displayed Back Button eturns to the previous screen while making system settings or checking status. Cover shown in the open position. Alarm O Button / Indicator (ed) Stops the tone that is emitted when an error occurs. Speaker Display Screen ( Next page) Status Button Check the status of the system or the number of installed unit(s) Lock Button Locks remote controller operation. Enter Button Confirms changes made by the user. emote Controller Part Number The part number is printed on the surface of the cover. Hot ater Temperature Setting Buttons For setting the hot water temperature the flow meter alarm, and other settings.

25 emote Controller (C-908M) Screen Display * The screen display shown below is for illustration purposes only. The actual display will vary depending on how the water heater is being used. * After a button is pressed, the display will gradually become darker to prevent unnecessary power consumption by the remote controller. Flame Symbol The flame symbol is displayed during combustion when using hot water or recirculation functions. Display for Temperature Setting During normal operation, the set temperature is displayed. Display for High Temperature Displays when the set temperature is F/ C ( F) or higher. Display for ecirculation Operation * For systems that use recirculation operation, the symbol is displayed when the power ON/OFF button is set to "ON". * It is displayed during the recirculation operation. Locked Display The lock symbol is displayed when the remote controller is locked. Temperature Setting (Ex.: 0 F) Clock Display (Ex.: AM0:) Normally the clock display is not shown when the power ON/OFF button is "OFF". * This setting can be changed so that the clock is displayed even when the power button is turned "OFF". ecirculation Timer The clock symbol is displayed when the recirculation timer is activated. Error Code A number will flash if a failure occurs. Note: As shipped from the factory, the remote controller is set to display in F and gallons. To adjust the display to C and liters, refer to the Installation Manual. hat is the home screen? The home screen is displayed when the button is "ON". Normally, the hot water temperature and the clock, etc. are displayed. <Home Screen Example>

26 . Operating Principle <NC98(-DV,-OD), NC8(-DV,-OD), NCC99(-DV,-OD) NC(-DV,-OD)> Exhaust Heat Exchanger Thermistor Exhaust Thermistor (DV only) Secondary Heat Exchanger Anti-Frost Heater ater level electrode High-Limit Switch Primary Heat Exchanger (DV only) Burner Thermal Fuse Condensate Trap Igniter Ignition Electrode Flame od (OD only) (DV only) Inlet Thermistor Impeller otational Frequency Sensor Air Supply Fan Motor Primary Gas Valve Filter Gas Proportioning Valve Switch Gas Solenoid Valve Gas Solenoid Valve Switch Gas Solenoid Valve ater volume servo Flow Control Valve ater Flow Sensor Outlet Thermistor ater Drain Valve ater Filter Pressure elief Device ater Drain Valve ater Drain trap Hot ater Supply ater Supply Gas Drain Hot ater Fixture Note: This diagram is for illustrative purposes only. Actual locations of the parts or connections may vary on the water heater.

27 <NC99(-DVC,-OD), N98(-DVC,-OD,-SV), N8-DVC> -SV -DVC Model Only Heat Exchanger Thermistor Exhaust High-Limit Switch Heat Exchanger Thermal Fuse Anti-Frost Heater Igniter Ignition Electrode Flame od Burner Bypass Flow Control Valve Main Flow Control Valve ater Flow Sensor Fan Motor otation Frequency Sensor ater Inlet Thermistor Air Supply Primary Gas Valve Filter Gas Proportioning Valve Gas Solenoid Valve Gas Solenoid Valve Gas Solenoid Valve Gas Solenoid Valve Circuit Board ater Outlet Thermistor Inpeller Air Inlet Thermistor L. P. Pressure elief Valve ater Drain Valve Hot ater Supply ater Drain Valve Pressure elief Valve (NCC Series Only) Cold ater Supply Hot ater Fixture ater Drain Valve ater Filter Gas Inlet 0VAC 7

28 < How to Use >. Normal Operation (Hot ater Production). Turn on the POE by pressing the "POE" button on the remote controller. (The priority lamp lights.). henever a hot water fixture is opened, or an appliance that requires hot water is turned on, as soon as the flow sensor detects at least the minimum flow rate required for initiating combustion, the fan will initiate and pre-purge any residual combustibles in the combustion chamber. The igniter will then create a spark and the gas valves will open, alllowing fuel into the combustion chamber where it will be ignited by the spark.. hen the flame rod detects a flame, the igniter stops sparking.. The computer will then control the gas and water control valves to maintain the water at the temperature set on the remote controller. The temperature can be adjusted using the "Setting Buttons" on the remote controller.. hen the demand for hot water ceases, the unit will stop heating: hen the flow sensor detects that the flow rate has dropped below the minimum rate for continued burning, the gas valves will close and the burner flame will go out. After the post purge removes residual gas from the combustion chamber, the unit stops. If necessary, turn off the power by pressing the "Operation Button" on the remote controller (the priority lamp will turn off).. Error Codes If the flame rod does not detect a flame, or if the high limit switch has been triggered, the gas valves will close, the flame will go out, and an error code will flash on the remote controller. In order to reset the unit and remove the error code, turn the power off by pressing the "Operation Button" on the remote controller, and then press it again to turn the unit back on. If the problem requires service (the thermal fuse is triggered, etc) the gas valves will stay closed and resetting the unit will not eliminate the error code. If this is the case, the unit must be serviced before it will work again.. Miscellaneous If the unit will not be used for a long period of time, turn off the power, drain the unit of water, and close the manual gas valve on the supply line. 8

29 . Operation Flow Chart NC98(-DV,-OD), NC8(-DV,-OD) ater heating Connect power Fix problem Main flow control valve moves to initial position setting Disconnect power Lightning safety device normal On/Off button turn ON arning indication The unit will continue to operature with the code blinking. Priority lamp turns OFF Error code stops flashing Priority lamp (yellow) lights Self-diagnosis Normal combustion possible 0 years or more of use Self-diagnosis Maximum output limited Normal combustion 90 possible arning indication arning indication 0 90 Turn power Off Self-diagnosis Normal combustion possible 99 Overheat prevention device (Thermal fuse) normal (Less than F) Stop hot water demand Main flow control valve operating normal Hot water demanded arning indication Condensate trap clogging Inlet thermistor open or shorted Outlet thermistor open or shorted 9 ater flow sensor detects > 0. GPM 7 Heat exchanger thermistor open or shorted Initial check normal 8 Exhaust thermistor open or shorted Circuit board abnormality 70 DV only * Inlet water high temperature check Normal 9 Abnormal gas solenoid valve drive circuit Flame rod circuit abnormality (A or more) Fan motor ON Fan motor stops Fan speed (target 00 rpm) (After 0 sec) (Fan abnormality) Igniter sparks Primary gas solenoid valve opens Gas solenoid valve opens Gas proportioning valve opens Flame rod detects > A Burner on lamp lights Igniter stops sparking st, th, 7th:after sec. ( others:after sec. ) Igniter stops sparking e-ignition (8 times or less) Extinction ( times or less) High limit switch is normal Primary gas solenoid valve Gas solenoid valve Gas proportioning valve Gas solenoid Valve Burner On Lamp goes off (Ignition failure) (Flame rod) 8 (High-limit switch) (rd) 0 Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve Burner On lamp goes off * If the inlet temp is less than F or if the following statements about K are true, the inlet temprature will be normal (). * Over 0,000 BTU Gas solenoid valve Gas solenoid valve Gas solenoid valve ON ON ON Approx. 8. K > + water inlet temperature ( F) Total water flow (GPM) Set temperature Less than F F or more K F Set temp +9 F Over Over Over Over 70,000,000 8,000,000 BTU BTU BTU BTU ON ON ON ON ON ON 7 Gas solenoid valve opens or (as necessary) * 90 9 At max BTU, is outlet water temp. less than setting 99 9 Main flow control valve activates Flow is adjusted Overheat prevention device (Thermal fuse) triggered ( F or more) Inlet thermistor open or shorted 7 Heat exchanger thermistor open or shorted Abnormal combustion 8 Exhaust thermistor open or shorted Condensate trap clogging 9 8 Safety device triggered Flame rod does not detect a flame (0.A or less) Outlet water temp. is too high Outlet thermistor open or shorted Fan speed abnormality * Using terms is equivalent to more than 0 years Exhaust thermistor is too high DV only * hen the present fan speed is 00rpm more or less than target speed. 9

30 Shutdown procedure On/Off button turn ON ater flow sensor detects < 0. GPM Burner On lamp goes off Gas proportioning valve Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Fan motor post purge Main flow control valve opens fully Fan motor stops Freeze prevention control Anti-frost heater operation flow Fan operation flow (DV only) Heat exchanger thermistor normal Heat exchanger thermistor 7 F or higher Heat exchanger thermistor 9 F or lower Fan Turn ON <,00 rpm> Heaters turn on 7 arning indication Air inlet thermistor normal Fan speed <Target 00 rpm> Heaters turn on 0 Air inlet thermistor Less than 7 F minutes later Heat exchanger thermistor 7 F or higher 0 minutes later Heaters turn on Fan Turn OFF Heat exchanger thermistor 7 F or higher Fan Turn OFF Heaters turn off * Has 0(or 0) min passed Heat exchanger thermistor 8 F or higher Heaters turn off Heat exchanger thermistor 8 F or higher * Has (or ) min passed * * hen less than 0 minutes after combustion, it is 0 F or higher. Differs depending on set temperature. Air inlet thermistor F or higher Fan operation flow (OD only) A Exhaust Th 0 C Freeze prevention fan Turn ON * Fan speed Normal Exhaust Th -0 C Freeze prevention fan operation Prohibition Exhaust Th 8 C or Exhaust Th A C * Heat exchanger Th 0 C Freeze prevention fan Fan Turn OFF A * : Target number of rotations (Freeze prevention fan in operation) F point Th 0 C :,000rpm F point Th > 0 C :,00rpm Hysteresis During,000rpm is controlled by F point Th 0 C, the condition for modifying into,00rpm is F point Th C. 0 * : Fan stopped exhaust Th temperature A.,000rpm control of * : A = 8 C.,00rpm control of * : A = C.

31 NCC99(-DV,-OD), NC(-DV,-OD) ater heating Shutdown procedure Connect power Fix problem Hot water fixture closed Bypass flow control valve and heat exchanger flow control valve move to initial position setting Disconnect power ater flow sensor detects < 0. GPM Lightning safety device normal ON/OFF button turn ON Set. Temp. indicates on the display Bypass and H.E. flow control valves open Self-diagnosis Normal combustion possible years or more of use Maximum output limited arning indication Self-diagnosis Normal combustion possible arning indication arning indication The unit will continue to operate with the error code blinking on the remote controller. Self-diagnosis Normal combustion possible Display turns OFF Error code stops flashing Turn power Off BUNE ON lamp goes off Gas proportioning valve Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Fan motor post purge Heat exchanger flow control valve opens fully Fan motor stops Overheat prevention device (Thermal fuse) normal (less than 0 F) Heat exchanger flow control valve normal Bypass flow control valve normal arning indication arning indication Inlet thermistor open or shorted Hot water fixture closed Has min. passed since hot water fixture closed Heat exchanger thermistor < 0 F Bypass flow control valve Setting F or higher Outlet thermistor open or shorted Bypass flow control valve 7 Heat exchanger thermistor open or shorted 8 Exhaust thermistor open or shorted <-DV model only> Hot water fixture opened Circuit board abnormality ater flow sensor detects > 0. GPM Abnormal gas solenoid valve drive circuit Initial check normal 9 Flame rod circuit abnormality (μa or more) Condensate drain trap Blockage * Inlet water high temperature check normal Fan motor stops 0 Fan motor ON Fan speed (target ± 00 rpm) (After 0 sec) e-ignition (8 times or less) Igniter sparks Extinction ( times or less) Primary gas solenoid valve opens High limit switch is normal (rd) Gas solenoid valve opens Gas solenoid valve opens Gas proportioning valve opens Flame rod detects μa BUNE ON lamp lights Igniter stops sparking Gas solenoid valve opens or (as necessary) * Gas solenoid valve opens or (as necessary) * Gas solenoid valve opens or (as necessary) * st, th, 7th: after sec. others: after sec. Igniter stops sparking Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve Gas solenoid Valve Gas solenoid Valve BUNE ON Lamp goes off Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve BUNE ON lamp goes off * If the inlet temp. is less than F or if the following statements about K are true, the inlet temperature will be normal () * Over Over 7,000 7,00 BTU BTU Gas solenoid valve ON ON Gas solenoid valve ON Gas solenoid valve ON Gas solenoid valve ON ON Approx. 9.7 K > + water inlet temperature ( F) Total water flow (GPM) Set temperature Less than F F or more K F Set temp. + 9 F Over Over Over Over,00,70 9,000,000 BTU BTU BTU BTU ON ON ON ON ON ON ON 9 Gas solenoid valve opens or (as necessary) * At max. BTU is outlet water temp. less than setting Heat exchanger flow control valve activates 8 Flow is adjusted Overheat prevention device (Thermal fuse) triggered(0 F or more) Condensate drain trap abnormality (check for blockage and electrode connections) Outlet thermistor open or shorted Exhaust thermistor open or shorted <-DV model only> Abnormal combustion Using terms is equivalent to more than 0 years 9 7 Safety device triggered Flame rod does not detect a flame (0.μA or less) Outlet water temp. is too high Inlet thermistor open or shorted Heat exchanger thermistor open or shorted Fan speed abnormality * Exhaust temperature is too high * hen the present fan speed is 00rpm more or less than target speed.

32 Freeze prevention control Anti-frost heater operation flow X = Heat exchanger thermistor Y = Air inlet thermistor Air inlet thermistor normal X < F or Y < 7 F 0 Heat exchanger thermistor normal Y < 8 F A Heaters turn ON DV or SV conversion model Heaters turn ON Heaters turn ON Exhaust thermistor normal X F and Y F X F and Y F Has 0 min passed Has 0 min passed Exhaust thermistor Less than 7 Heaters turn OFF Heaters turn OFF Heaters turn ON X F and Y F A X F and Y F A Exhaust thermistor F or higher Has min passed Has min passed Has 0 min passed Heaters turn OFF Exhaust thermistor Less than 7 Fan motor operation flow ( SV conversion ) Fan motor operation flow ( DV model ) Exhaust thermistor No error code Exhaust thermistor 8 Fan motor stopped No error code Air inlet thermistor Higher than Air inlet thermistor Higher than Air inlet thermistor Fan Turn ON <,00 rpm > Fan Turn ON <,000 rpm > Fan Turn ON <,00 rpm > Fan speed set,000 rpm Fan speed set,00 rpm minutes Fan speed,00 00rpm Exhaust thermistor higher than Fan Turn OFF Fan Turn OFF Exhaust thermistor Exhaust thermistor Fan speed Target 00rpm Exhaust thermistor Heat exchanger thermistor 8 Fan Turn OFF * Exhaust thermistor X or higher Heat exchanger thermistor 8 Fan Turn OFF * hen fan speed is,00rpm, X = F. * hen fan speed is,000rpm, X = 9 F.

33 NC99(-DVC,-OD), N98(-DVC,-OD,-SV) ater heating Shutdown procedure Connect power Fix problem Hot water fixture closed Bypass flow control valve and heat exchanger flow control valve move to initial position setting Disconnect power ater flow sensor detects < 0. GPM Lightning safety device normal ON/OFF button turn ON Set. Temp. indicates on the display Bypass and H.E. flow control valves open Self-diagnosis Normal combustion possible years or more of use Maximum output limited arning indication arning indication The unit will continue to operate with the error code blinking on the remote controller. arning indication Self-diagnosis Normal combustion possible Display turns OFF Error code stops flashing Turn power Off Gas proportioning valve Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Fan motor post purge Heat exchanger flow control valve opens fully Self-diagnosis Normal combustion possible Fan motor stops Overheat prevention device (Thermal fuse) normal (less than 0 F) Has min. passed since hot water fixture closed Heat exchanger flow control valve normal arning indication Heat exchanger thermistor < 0 F Bypass flow control valve normal arning indication Hot water fixture closed Bypass flow control valve Setting F or higher Bypass flow control valve Inlet thermistor open or shorted Outlet thermistor open or shorted Hot water fixture opened 7 Heat exchanger thermistor open or shorted ater flow sensor detects > 0. GPM Circuit board abnormality Abnormal gas solenoid Initial check normal 8 valve drive circuit Flame rod circuit abnormality (μa or more) * Inlet water high temperature check normal Fan motor stops 9 Fan motor ON 0 7 Fan speed (target ± 00 rpm) Igniter sparks Primary gas solenoid valve opens Gas solenoid valve opens Gas solenoid valve opens Gas proportioning valve opens Flame rod detects μa Igniter stops sparking Gas solenoid valve opens or (as necessary) * Gas solenoid valve opens or (as necessary) * Gas solenoid valve opens or (as necessary) * (After 0 sec) st, th, 7th: after sec. others: after sec. < SV model only > st: after sec. others: after sec. Igniter stops sparking < SV model only > ( times or less) < SV model only > ( times or less) e-ignition (8 times or less) Extinction ( times or less) Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve High limit switch is normal Gas solenoid Valve Gas solenoid Valve BUNE ON Lamp goes off (rd) 9 Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve BUNE ON lamp goes off * If the inlet temp. is less than F or if the following statements about K are true, the inlet temperature will be normal () * Over Over 7,000 7,00 BTU BTU Gas solenoid valve ON ON Gas solenoid valve ON Gas solenoid valve ON Gas solenoid valve ON ON Approx. 9.7 K > + water inlet temperature ( F) Total water flow (GPM) Set temperature Less than F F or more K F Set temp. + 9 F Over Over Over Over,00,70 9,000,000 BTU BTU BTU BTU ON ON ON ON ON ON ON 8 Gas solenoid valve opens or (as necessary) * At max. BTU is outlet water temp. less than setting Heat exchanger flow control valve activates Flow is adjusted Overheat prevention device (Thermal fuse) triggered(0 F or more) Inlet thermistor open or shorted 7 Heat exchanger thermistor open or shorted Abnormal combustion < SV model only > The air inlet filter may be clogged. 8 0 Safety device triggered Flame rod does not detect a flame (0.μA or less) Outlet water temp. is too high Outlet thermistor open or shorted Fan speed abnormality * Using terms is equivalent to more than 0 years * hen the present fan speed is 00rpm more or less than target speed.

34 Freeze prevention control Anti-frost heater operation flow Fan motor operation flow ( SV model ) X = Heat exchanger thermistor Y = Air inlet thermistor X = Heat exchanger thermistor Y = Air inlet thermistor 0 Air inlet thermistor normal Heat exchanger thermistor normal Heat exchanger thermistor normal 0 minutes after combustion Heaters turn ON X < F X < F or Y < 7 F X < F Y < 8 F Fan motor stopped A Heaters turn ON Heaters turn ON Air inlet thermistor normal X F and Y F X F and Y F Y F Has 0 min passed Has 0 min passed Fan turn ON <,00rpm > Heaters turn OFF Heaters turn OFF Fan speed target ±00rpm X F and Y F A X F and Y F A Y 0 F Has min passed Has min passed Has 0 min passed Fan turn OFF

35 N8-DVC ater heating Shutdown procedure Connect power Fix problem On/Off button turn ON Main flow control valve moves to initial position setting Lightning safety device normal On/Off button turn ON Priority lamp (yellow) lights Self-diagnosis Normal combustion possible arning indication The unit will continue to operature with the code blinking. 0 years or more of use Maximum output limited Self-diagnosis Normal combustion 90 possible arning indication arning indication 0 90 Disconnect power Priority lamp turns OFF Error code stops flashing Turn power Off ater flow sensor detects < 0. GPM Burner On lamp goes off Gas proportioning valve Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Fan motor post purge Main flow control valve opens fully Fan motor stops Self-diagnosis Normal combustion possible 99 Freeze prevention control Anti-frost heater operation flow Overheat prevention device (Thermal fuse) normal (Less than F) Main flow control valve operating normal Hot water demanded arning indication Inlet thermistor open or shorted Outlet thermistor open or shorted Heat exchanger thermistor open or shorted Stop hot water demand arning indication 0 Heat exchanger thermistor normal Heat * exchanger thermistor F or higher 7 Air inlet thermistor normal Air inlet thermistor Less than 7 F ater flow sensor detects > 0. GPM Circuit board abnormality 70 Heaters turn on 8 Initial check normal * Inlet water high temperature check Normal Fan motor ON 7 Abnormal gas solenoid valve drive circuit Flame rod circuit abnormality (A or more) 7 7 Fan motor stops (Fan abnormality) * Has 0(or 0) min passed Heaters turn off * Has (or ) min passed Air inlet thermistor F or higher 9 Fan speed (target 00 rpm) (After 0 sec) e-ignition (8 times or less) (Ignition failure) * * hen less than 0 minutes after combustion, it is 0 F or higher. Differs depending on set temperature. 0 Igniter sparks Primary gas solenoid valve opens Gas solenoid valve opens Gas proportioning valve opens Flame rod detects > A Burner on lamp lights Igniter stops sparking st, th, 7th:after sec. ( others:after sec. ) Igniter stops sparking Extinction ( times or less) High limit switch is normal Primary gas solenoid valve Gas solenoid valve Gas proportioning valve Gas solenoid Valve Burner On Lamp goes off (Flame rod) (High-limit switch) (rd) 0 Primary gas solenoid valve Gas solenoid valve Gas solenoid valve Gas solenoid valve Gas proportioning valve Burner On lamp goes off * * If the inlet temp is less than F or if the following statements about K are true, the inlet temprature will be normal (). Gas solenoid valve Gas solenoid valve Gas solenoid valve Over 0,000 BTU ON ON ON K > Approx. 8. Total water flow (GPM) Set temperature Over 7,000 BTU ON ON K Less than F + water inlet temperature ( F) F or more F Set temp +9 F Over,000 BTU ON ON Over 8,000 BTU ON Over 8,000 BTU ON Gas solenoid valve opens or (as necessary) * 90 At max BTU, is outlet water temp. less than setting 99 Main flow control valve activates Flow is adjusted Overheat prevention device (Thermal fuse) triggered ( F or more) Inlet thermistor open or shorted Heat exchanger thermistor open or shorted Abnormal combustion 7 9 Safety device triggered Flame rod does not detect a flame (0.A or less) Outlet water temp. is too high Outlet thermistor open or shorted Fan speed abnormality * Using terms is equivalent to more than 0 years * hen the present fan speed is 00rpm more or less than target speed.