Navien NFC-175, NFC-200 Service Manual

Service Manual
NFC Condensing Boilers
Model
NFC-175
NFC-200
Keep this manual near this boiler for future reference whenever maintenance or service is required.
WARNING
If the information in these instructions is not followed exactly, a fire or explosion may result, causing property damage, personal injury, or death.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or the gas supplier.
Revisions
Version Description of changes Date
1.0 First Issue December / 2018
2 NFC Service Manual
Version 1.0
NFC Service Manual 3
Version 1.0
Contents
1. Safety Information 9
1.1 Safety Definitions 9
1.2 Safety Symbols
9
1.3 Symbols Used in the Instructions
9
1.4 Safety Precautions
9
2. Product Information 13
2.1 Product Information Items 13
2.2 Components
14
3. Technical Data 16
3.1 Specifications 16
3.2 Dimensions
19
4. System Details 20
4.1 DIP Switch 1 (6 switch unit) 20
4.2 Dip Switch 2 (8 switch unit)
20
4.3 Measuring the Inlet Gas Pressure
21
4.3.1 Gas Pipe Sizing Tables 23
4.4 Gas & High Altitude Conversion
25
4.5 The Front Panel
32
4.5.1 Icons and Digital Display 32
4.5.2 Buttons and Command dial 33
4.6 Turning the Boiler On or Off
34
4.7 Adjusting the Temperature
34
4.7.1 Adjusting the Space Heating Temperature 34
4.7.2 Adjusting the DHW Temperature 35
4.7.3 Resetting the Boiler 35
4.8 Accessing Basic Menu Items
36
4.8.1 Quick Setup Menu 36
4.8.2 Viewing Basic Information 36
4.8.3 Setting the Space Heating Operation 37
4.8.4 Setting the DHW Operation 38
4.8.5 Viewing Error History 41
4.8.6 Viewing Other System Information 41
4.8.7 Setting the Display Options 42
4.9 Accessing Advanced Menu Items 42
4.9.1 Viewing Service Information 42
4.9.2 Viewing Input and Output Status 43
4.9.3 Setting the Operation Parameters 43
4.9.4 Configuring a Cascade System 46
4.9.5 Setting the External Connection (for NaviLink) 47
4.9.6 Diagnosing the Boiler System 47
4.9.7 Setting the Special Operation Modes 48
4.10 Ladder Diagram
49
4.11 Wiring Diagram
50
4.12 Key Components Description
52
4.12.1 PCB 52
4.12.2 High Limit Switch 53
4.12.3 Thermistor 54
4.12.4 Fan Motor 55
4.12.5 Flame Rod Assembly 56
4.12.6 Ignition Transformer 57
4.12.7 APS 58
4.12.8 Main Gas Valve 59
4.12.9 Burner 60
4.12.10 Heat Exchanger Assembly 61
4.12.11 Water Pressure Sensor 62
4.12.12 Dual Venturi 63
4.12.13 DHW Heat Exchanger 64
4.12.14 3-Way Valve 65
5. Troubleshooting 66
5.1 Error code classification 66
5.2 Error code classification
68
5.2.1 001Error 72
5.2.2 003Error 74
5.2.3 004Error 80
5.2.4 012Error 81
5.2.5 016Error 84
5.2.6 030Error 86
5.2.7 046Error 88
5.2.8 047Error 88
5.2.9 060Error 89
5.2.10 109Error 91
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7. Components Diagram and Part List 126
7.1 Case Assembly 126
7.2 Heat Exchanger and Waterway Assembly
128
7.3 Combustion Parts Assembly
130
8. Inspection and Maintenance Schedule 132
8.1 Annual Servicing 132
8.2 Maintenance Report
132
8.3 Maintenance Schedules
132
8.4 Inspection Report
132
5.2.11 110Error 93
5.2.12 205Error 95
5.2.13 218Error 97
5.2.14 278Error 99
5.2.15 279Error 100
5.2.16 291Error 101
5.2.17 302Error 102
5.2.18 351Error 103
5.2.19 352Error 104
5.2.20 353Error 105
5.2.21 407Error 106
5.2.22 421Error 107
5.2.23 434Error 108
5.2.24 439Error 109
5.2.25 441Error 110
5.2.26 445Error 111
5.2.27 515Error 112
5.2.28 517Error 113
5.2.29 594Error 113
5.2.30 615Error 114
5.2.31 740Error 114
5.2.32 777Error 115
5.2.33 782Error 116
5.2.34 784Error 116
5.2.35 777 & 031Error 117
5.3 Troubleshooting guide by symptom
119
5.3.1 Noise 119
5.3.2 Water Temperature Issue 120
6. Replacement of Parts 121
6.1 Replacement Procedure 121
6.2 Components Replacement Instructions
121
6.2.1 PCB 121
6.2.2 Fuse 122
6.2.3 Fan (Combustion Air) 122
6.2.4 Flame Rod 123
6.2.5 Ignition Transformer 123
6.2.6 APS 124
6.2.7 Main Gas Valve 125
6.2.8 Water Pressure Sensor 125
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Requirements for the State of Massachusetts
NOTICE BEFORE INSTALLATION
This appliance must be installed by a licensed plumber or gas fitter in accordance with the Massachusetts Plumbing and Fuel Gas Code 248 CMR Sections 4.00 and 5.00.
IMPORTANT: In the State of Massachusetts (248 CMR 4.00 & 5.00)
For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. No installation or replacement of a vented gas appliance shall be permitted unless a battery powered or electrically hard wired carbon monoxide detector is present on the same floor as the appliance or on the next adjacent floor when the appliance is 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 the dwelling. These requirements shall not be deemed to waive any additional requirements imposed by M.G.L. c. 148 §26F1/2.
2. APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE. Whenever any through-the-wall vent is installed less than seven feet above the finished grade, a metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight feet above grade directly in line with the exhaust vent terminal. The sign shall read, in print size no less than 0.5 inches in size,“GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS”.
4. INSPECTION. The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR 5.09 and 5.12.
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Navien will pay labor charges for the repair subject to Navien’s prior written approval and in accordance with Navien’s schedule of approved labor allowances for a period of one (1) year from the date of installation. All repair parts must be genuine Navien parts. All repairs and replacements must be performed by an individual or servicing company that is properly licensed to do the type of repair.
When the Product is or has ever been used for anything other than single family residential application (hereinafter “Commercial”) then the parts warranty will be reduced to three (3) years and the heat exchanger warranty to ten (10) years.
During the applicable warranty period, replacement of the Product or components may be authorized by Navien only. Navien does not authorize any person or company to assume for it any obligation or liability in connection with the replacement of the Product or its components. If it is determined that repair or replacement of a part, under warranty, is not possible, the Product will be replaced with a new Product having at least the same BTU capacity as the product at issue. The replacement component or product will be warranted only for the unexpired portion of the applicable warranty period for the original component or Product.
The heat exchanger is covered by Navien’s pro-rated limited residential Warranty for defects in material and workmanship at a cost to the customer equal to a percentage of the Manufacturer’s Suggested Retail Price (MSRP), at the time the warranty claim is approved by Navien, as indicated in the following Coverage Table for Heat Exchangers Only. This pro-rated warranty only applies to the replacement of the heat exchanger and does not include labor, shipping, other parts, delivery or installation. In order to obtain this warranty, the customer must pay the applicable pro-rated amount as indicated in the following Coverage Table for Heat Exchangers Only. Once the customer pays the pro-rated amount, then Navien will ship the heat exchanger directly to the service provider.
Warranty Claim Procedures
To obtain warranty repair service, the end user or homeowner must contact the original installer of your Navien product. If the original installer cannot be identified, the end user or homeowner may contact Navien’s Technical Administration Department at 1-800-519-8794. Proof of purchase is required to obtain warranty service.
Warranty Service
At its option, Navien will replace the defective component (part(s) or heat exchanger), in accordance with the terms of this Limited Warranty, if it fails in normal use and service during the Applicable Warranty Period identified above. The replacement component must be Navien original factory component. Navien, at its sole discretion, may replace the product with a new or refurbished product of comparable quality and design. The replacement component or product will be warranted only for the unexpired portion of the original component’s Applicable Warranty Period. Payment for labor in completing the warranty service is subject to Navien’s prior written approval and shall be subject to Navien’s schedule of approved labor allowances.
Warranty Period
Navien products come with a limited warranty covering labor, parts and the heat exchanger. The following warranty periods begin to run from the date of original installation. The date of original installation must be provided to Navien, and upon request, proof of the original installation date must also be provided to Navien. When the product is installed in a new construction, the commencement date shall be dated upon which the end-user takes title to the property.
Warranty Period
Coverage Table for Labor and Parts Only
Residential* Commercial
Labor 1 year Labor 1 year
Parts 5 years Parts 3 years
* Applies only to single family, residential locations.
Coverage Table for Heat Exchangers Only
Residential* Commercial
Years
Percentage Paid by
Customer
Years
1 to 12 0 %
10
13 50 %
14 60 %
15 70 %
* Applies only to single family, residential locations.
Effective
This 10/15 year limited pro-rated warranty on heat exchangers, 3/5 year limited warranty on parts, and 1 year limited-labor warranty (“Warranty”) covers defects in materials or workmanship when the Navien NFC Boiler (“Product”) is installed by a properly licensed plumber or contractor and operated in strict compliance with the Installation & Operations manual procedures, subject to the terms within this Warranty document. Improper installation or use will void this Warranty. This Warranty runs from date of installation and extends to the original purchaser and subsequent owners, but only while the Product remains at the site of the original installation. This Warranty includes both a limited and pro-rated warranty as set forth below.
What is Covered?
Subject to the foregoing terms, Navien will repair or replace the covered Product or any part or component that is defective in materials or workmanship for a period of five (5) years in regard to parts and up to twelve (12) years in regard to the heat-exchanger.
Navien Warranty
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Warranty Exclusions
Navien’s Limited Warranty shall be void in the event of an occurrence of any of the following:
Improper installation, failure to install in strict compliance with the Installation Manual procedures, installed by a non-licensed installer, and installation in violation of applicable rules, laws or building codes.
Product purchased through the internet, other e-commerce channels, or any installer that obtained the Product from a supplier or distributor not authorized by Navien.
Failure to perform regular maintenance, misuse, operation at settings other than those recommended or specified, non­compliance with instructions or guidelines set forth in the User’s Operation Manual.
Modification or alteration of the Product in any manner, including but not limited to, removal of any component or part, addition of any non-approved components, relocating or moving the Product from its original installation site, or any accidental or intentional damage to the Product.
Installation for non-recommended uses.
Any damage caused by local adverse conditions including but not limited to hard water deposits, lime or mineral build-up, operating in corrosive atmospheric elements.
Damage caused by gas flow issues, electrical surges, flooding, fire, abnormal external temperature, and any other cause of damage not directly caused by a manufacturing defect.
Installer’s failure to fully comply with the Warranty Service and Return Policy procedures previously provided to Installer and as is available on Navien’s website. Such policies include but are not limited to the Installer’s failure to first contact Navien Technical Support while in front of the product for purposes of trouble shooting the identified problem or issue.
Performance problems caused by improper sizing of the boiler, the gas supply line, the venting connection, combustion air openings, electric service voltage, wiring, fusing or any other components, parts or specifications.
Improper conversion from natural gas to LP gas or LP gas to natural gas or attempt to operate with a type of gas not specified for the boiler.
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 contaminated atmosphere or environment.
Operating the boiler at water temperatures outside the factory calibrated temperature limits and/or exceeding the maximum setting of the high limit control.
Operating the boiler when it is not supplied with potable water at all times.
Subjecting the heat exchanger to pressures or firing rates greater or lesser than those shown on the rating plate.
Installation at any location outside the United States and Canada.
Removal or alteration of the rating plate.
NFC-175
NFC-200
Other Terms: This Limited Warranty is subject further to the terms and conditions set forth herein and as may be further specified in the Terms and Conditions page located on Navien’s website at www.navien.com. WITH THE EXCEPTION OF THIS LIMITED WARRANTY, NAVIEN DISCLAIMS ANY OBLIGATION OR LIABILITY WITH RESPECT TO THE PRODUCTS OR THEIR SALE AND USE, AND NAVIEN NEITHER ASSUMES NOR AUTHORIZES THE ASSUMPTION OF, ANY OBLIGATION OR LIABILITY IN CONNECTION WITH THE PRODUCTS. THIS DISCLAIMER INCLUDES ANY OTHER WARRANTIES, EXPRESS, IMPLIED OR STATUTORY RESPECTING THE PRODUCTS OR ANY PARTS OR COMPONENTS THEREOF, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Navien’s total liability for any claim arising hereunder shall not exceed the purchase price which you paid for the Product. NAVIEN SHALL NOT IN ANY EVENT BE LIABLE FOR INDIRECT, SPECIAL, CONSEQUENTIAL OR LIQUIDATED DAMAGES OR PENALTIES, INCLUDING CLAIMS FOR LOST REVENUE, PROFITS OR BUSINESS OPPORTUNITIES, EVEN IF NAVIEN HAD OR SHOULD HAVE HAD ANY KNOWLEDGE, ACTUAL OR CONSTRUCTIVE, OF THE POSSIBILITY OF SUCH DAMAGES.
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Abbreviations and Definitions
Abbreviation Definition
NFC General name of NFC-175, NFC-200
NG Natural Gas
LP Propane Gas
AP Air Pressure
APS Air Pressure Sensor
DHW Domestic Hot Water
FM Fan Motor
GPM Gallons Per Minute
MGV Main Gas Valve
RPM Revolutions Per Minute
PCB Printed Circuit Board
EMI Electromagnetic Interface
HTL High Temperature Limiter
LWCO Low Water Cut Off
NFC Service Manual 9
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1.3 Symbols Used in the Instructions
IMPORTANT
Warns of a risk of damage and environmental pollution
Note
Indicates additional information that is important but not related to personal injury or property damage.
1.4 Safety Precautions
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 combustibles such as newspapers and laundry etc. near the boiler or the venting system.
DO NOT place or use hair spray, spray paint or any other type of spray can near the boiler or the venting system (including the vent termination).
DO NOT place anything in or around the vent terminations that could obstruct the air flow in and out of the boiler such as a clothes line.
1.1 Safety Definitions
The following safety symbols are used in this manual. Read and follow all safety instructions in this manual precisely to avoid unsafe operating conditions, fire, explosion, property damage, personal injury, or death.
1.2 Safety Symbols
DANGER
Indicates an imminently hazardous situation which, if not avoided, could result in severe injury or death.
WARNING
Indicates a potentially hazardous situation which, if not avoided, could result in injury or death.
CAUTION
Indicates a potentially hazardous situation that, if not avoided, could result in property damage.
1. Safety Information
10 NFC Service Manual
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DANGER
If you smell gas:
Do not try to light any appliance.
Do not touch any electrical switches or use landline phones.
From a neighbor’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 fire department.
Do not use or store flammable products, such as gasoline, solvents, or adhesives in the same room or area as the boiler.
The boiler has a main burner flame that can turn on at any time and can ignite flammable vapors. Vapors from flammable liquids can explode and catch fire, causing death or severe burns.
Vapors cannot be seen and are heavier than air. They can travel long distances along the ground and can be carried from other rooms to the boiler’s main burner flame by air current.
Keep all flammable products far away from the boiler and store them in approved containers. Keep the containers closed tightly and out of the reach of children and pets.
DANGER
COMPROMISED VENTING SYSTEM
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 the boiler unless it is properly vented to the outside and has an adequate air supply for proper operation.
Be sure to inspect the vent termination and the air intake pipe annually to ensure safe operation of the boiler.
Immediately turn off and do not use the boiler if any of the vent pipes, vent elbows and/or the boiler are:
-
damaged in any way;
-
separated at a joint,
-
cracked or show evidence of corrosion, rusting or melting.
DANGER
WHAT TO DO IF YOU SMELL GAS
If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
DO NOT OPERATE THE BOILER. DO NOT OPERATE ANY FAUCETS. Smell all around the appliance area for gas. Be sure to smell
next to the floor because some gas is heavier than air and will settle on the floor.
Do not smoke.
Extinguish any open flames and sparks.
Do not operate light switches or electrical equipment switches.
Do not use any phone in your building.
Open the windows and doors.
Close the gas shutoff valve.
Keep people away from the danger zone.
Observe the safety regulations of your local gas supplier, found on the gas meter.
Immediately call your gas supplier from the outside of the building. Follow the gas supplier’s instructions.
If you cannot reach your gas supplier, call the fire department.
Notify your plumbing/heating contractor from the outside of the building.
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DANGER
INSTALLATION REQUIREMENTS
Installation conditions may affect how the boiler is serviced. Read all related information in the “Installation Manual”.
The Boilers must be installed according to all local and state codes or, in the absence of local and state codes, the most recent edition of the “National Fuel Gas Code (ANSI Z223.1 / NFPA 54)” in the USA or the “National Gas and Propane Installation Code (CAN / CSA B 149.1)” in Canada.
Massachusetts code requires this boiler to be installed in accordance with Massachusetts Plumbing and Fuel Gas Code 248 CMR Section 2.00 and 5.00.
DANGER
IMPORTANT SAFETY PREAUTIONS
Read and understand this safety information before operating or servicing this Navien Boiler.
Confirm the location of the gas shut-off valve. Close the manual shut-off valve if the Navien Boiler ever becomes subjected to overheating, fire, flood, physical damage or any other such damaging condition during servicing.
DO NOT turn on the boiler unless water and gas supplies are fully opened.
DO NOT turn on the boiler if the cold water supply shut-off valve is closed.
Make certain power to the boiler is “OFF” before removing the front cover for any reason.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.
Improper adjustment, alteration, service or maintenance can cause property damage, personal injury, or death.
To prevent scalding, always check the temperature of the hot water after servicing.
DO NOT attempt to change the water temperature while someone is using the boiler.
DO NOT use parts other than those specified for this equipment.
DO NOT operate the boiler if you feel something is wrong with the unit.
DO NOT allow children to operate or otherwise handle the unit.
WARNING
GAS TYPE and AC VOLTAGE
This boiler is configured for Natural Gas from the factory. If conversion to Propane Gas is required, the conversion kit supplied with the boiler must be used.
Be sure to use 120 VAC, 60 Hz, minimum 2 A current. Using abnormally high or low AC voltage may cause abnormal operation, and may reduce the life expectancy of this product.
If the unit does not match requirements, do not service, please contact Navien immediately.
WARNING
GAS CONVERSION
The conversion kit shall be installed by a qualified service agency* in accordance with Navien’s instructions and all applicable codes and requirements of the authority having jurisdiction. The information in these instructions must be followed to minimize the risk of fire or explosion or to prevent property damage, personal injury or death. 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 specified in the manufacturer’s instructions supplied with the kit.
* A qualified service agency is any individual, firm, corporation
or company which either in person or through a representative is engaged in and is responsible for the connection, utilization, repair or servicing of gas utilization equipment or accessories; who is experienced in such work, familiar with all precautions required, and has complied with all of the requirements of the authority having jurisdiction.
In Canada: The conversion shall be carried out in accordance
with the requirements of the provincial authorities having jurisdiction and in accordance with the requirements of the CAN-B149.1 and CAN1-B149.2 Installation Code.
Navien Inc. is not liable for any property damage and/or personal injury resulting from unauthorized conversions.
California law requires the following Prop 65 warning to be provided:
WARNING
This product can expose you to chemicals including lead, lead
compounds, and carbon bisulfide which are known to the
State of California to cause cancer and birth defects or other
reproductive harm. For more information, go to
www.P65Warnings.ca.gov.
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WARNING
Shut off the gas supply if the boiler is damaged.
Have your installer or plumber show you the location of the gas shut off valve and demonstrate how to close the valve. If the boiler is damaged as a result of overheating, fire, flood, or any other reason, close the manual shut off valve and do not operate the boiler again until it has been inspected by a qualified technician.
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 venting system.
Doing so may result in a fire.
Do not place or use hair sprays, spray paints, or any other compressed gases near the boiler or venting system, including the vent termination.
Doing so may result in fire or explosion.
Do not operate the boiler with the front cover opened.
Doing so may result in fire or carbon monoxide (CO) poisoning, which may result in property damage, personal injury, or death.
Do not operate this boiler without proper venting.
Doing so may result in fire or carbon monoxide (CO) poisoning, which may result in property damage, personal injury, or death. Inspect the vent termination and air intake supply annually to ensure proper operation of the boiler. Turn off and discontinue use of the boiler if any of the vent pipes, vent elbows, or intake pipes are damaged in any way, separated at a joint, or show evidence of corrosion, rusting, or melting.
Do not touch the power cord or internal components of the boiler with wet hands.
Doing so may result in electric shock.
CAUTION
Do not attempt to repair or replace any part of the boiler, unless it is specifically recommended in this manual.
For all other service, contact an authorized technician or licensed professional. Improper adjustments, alterations, service, or maintenance may lead to property damage, personal injury, or death and will void your warranty.
Do not operate the boiler if you feel something is wrong with it.
Doing so may result in product damage or personal injury.
Do not allow children to operate or access the boiler.
Doing so may result in product damage or personal injury.
Do not attempt to change the water temperature while the boiler is being used.
Doing so may result in personal injury.
Do not turn on the boiler unless the water and gas supplies are fully opened.
Doing so may damage the boiler.
Do not turn on the water if the cold water supply shut­off valve is closed.
Doing so may damage the boiler.
Do not use this boiler for anything other than its intended purpose, as described in this manual.
Do not remove the front cover unless the power to the boiler is turned off or disconnected.
Failure to do so may result in electric shock.
When servicing the controls, label all wires prior to disconnecting them.
Failure to do so may result in wiring errors, which can lead to improper or dangerous operation.
Do not use unapproved replacement or accessory parts.
Doing so may result in improper or dangerous operation and will void the manufacturer’s warranty.
Do not place anything in or around the vent terminals, such as a clothes line, that could obstruct the air flow in or out of the boiler.
This boiler has been approved for use in the USA and Canada only.
Using the boiler in any other country will 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.
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2.1 Product Information Items
Navien features the NFC Series gas boiler. This appliance is fully modulating and provides central heating. Depending on the heat capacity, each model is divided into two types; 175 and 200.
Model Maximum Space Heating Input
NFC-175 175,000 BTU/h
NFC-200 199,000 BTU/h
A separate heating expansion vessel is required.
Internal freeze protection and an electronic control unit are incorporated within the boiler. Any standalone room thermostat or set of contacts can be used with the boiler.
2. Product Information
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2.2 Components
The following diagram shows the key components of the boiler. Component assembly diagrams and particular parts lists are included in the Appendixes.
Intake Air
Air Intake Pipe
Exhaust
Fan & Motor Assembly
Dual Venturi
APS
PCB
Power Switch
PRV-Air Vent Connection
Gas Pipe
Mixing Chamber
Igniter
Flame Rod
Igniter Transformer
Fire-Tube Type
Heat Exchanger
ASME Name Plate
Front Panel
Gas Valve
Condensate Outlet
24V Power Transformer
Gas Inlet
Condensate Trap (Siphon)
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Terminal Block
Dual Venturi
Fan & Motor Assembly
Igniter Transformer
Fire-Tube Type
Heat Exchanger
APS
Power Switch
Mixing Valve
3-Way Valve
Heating Return
Gas Valve
ASME Name Plate
Mixing Chamber
Intake Air Filter
Flame Rod
Igniter
Circulation Pump
Water Adjust Valve
DHW Exchanger
Water Fill Valve
Heating Supply
DHW Inlet
DHW Outlet
Condensate Trap (Siphon)
PCB
Front Panel
Gas Pipe
Air Intake Pipe
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3.1 Specifications
The following tables list the specifications for the boiler. Additional specifications for water, gas, electricity, and vent connections are provided in the Installation section.
Space Heating Specifications
Navien Condensing Boiler
Space Heating Ratings
Other Specifications
Model Number
1
Heating Input (MBH) Heating
Capacity
2
(MBH)
Net AHRI
Rating Water
3
(MBH)
AFUE2 (%)
Water
Pressure
Water Connection Size (Supply, Return)
Water
Volume
Min Max
NFC-175 18 175 161 140 95
12–80 psi 1 in NPT 4.5 gallons
NFC-200 18 199 183 159 95
Note
1. Ratings are 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. Consult Navien before selecting a boiler for installations having unusual piping and pickup requirements, such as intermittent system operation, extensive piping system, etc.
Domestic Hot Water Specifications
Item NFC-175 NFC-200
Input Ratings
Min 18,000 BTU/H 18,000 BTU/H
Max 199,900 BTU/H 199,900 BTU/H
Water Pressure 15-150 psi
Minimum Flow Rate 0.5 GPM (1.9 L/m)
Flow Rate 45°F (25°C) Temp. Rise 7.9 GPM
DHW Supply Connection Size
3
/4 in NPT
Cold Water Input Connection Size
3
/4 in NPT
3. Technical Data
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NFC Internal Pump
The NFC boiler is equipped with an internal circulation pump. The following table provides detailed information on the pump used for the boiler and the performance curve.
Item Pump Model
NFC-175/200
Internal Recirculation Pump
Grundfos UPS 15-78 CIL2
(Part Number: 30021636A)
0
5
10
15
20
25
30
0
2
4
6
8
10
12
14
16
0 2 4 6 8 10 12 14 16
FT of Head
P (psi)
Flow Rate (GPM)
NFC Flow Performance Curve
NFC-175/200 Grundfos Circulator Sp3 (Default) Grundfos Circulator Sp2 Grundfos Circulator Sp1
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General Specifications
Item NFC-175 NFC-200
Dimensions 17.3 in (W) x 17.3 in (D) x 33.5 in (H)
Boiler Weight 145 lb (66 kg)
Boiler Weight with Water 183 lb (83 kg)
Installation Type Indoor Wall-Hung
Venting Type Forced Draft Direct Vent
Ignition Electronic Ignition
Natural Gas Supply Pressure (from source) 3.5 in–10.5 in WC
Propane Gas Supply Pressure (from source) 8.0 in–13.5 in WC
Natural Gas Manifold Pressure -0.05 to -0.47 in WC -0.05 to -0.20 in WC
Propane Gas Manifold Pressure -0.10 to -0.45 in WC -0.10 to -0.45 in WC
Flow Rate (DHW)
35°F (19°C) Temp Rise 10.4 GPM (39.5 L/m)
45°F (25°C) Temp Rise 7.9 GPM (30.0 L/m)
67°F (37°C) Temp Rise 5.4 GPM (20.3 L/m)
Gas Connection Size
3
/4 in NPT
Power Supply
Main Supply 120V AC, 60Hz
Maximum Power Consumption
Less than 15 amperes
Materials
Casing Cold-rolled carbon steel
Heat Exchangers Stainless Steel
Venting
Exhaust
2 in or 3 in PVC, CPVC, approved polypropylene*
2 in or 3 in Special Gas Vent Type BH (Class III, A/B/C)
2 in or 3 in Stainless Steel
Intake
2 in or 3 in PVC, CPVC, polypropylene
2 in or 3 in Special Gas Vent Type BH (Class III, A/B/C)
2 in or 3 in Stainless Steel
Vent Clearance 0 in to combustibles
Safety Appliances
Flame Rod, APS, Ignition Operation Detector Water Temperature High Limit Switch, Exhaust Temperature High Limit Sensor, Water Pressure Sensor
Temperature Setting Range
Item Temperature Setting Range Remarks
Space Heating
Supply 77–194°F (25-90°C)
Actual supply and return temperatures vary depending on the selected outdoor reset curve.
Return 68–158°F (20-70°C)
DHW 89°F-140°F (30°C-60°C)
Note
For more information about the space heating temperature setting range, refer to “4.8.3 Setting the Space Heating Operation” on page 37.
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3.2 Dimensions
The following diagrams show the dimensions of the boiler and the table lists the supply connections.
33.5" (850mm)
Supply Connections
Description Diameter
A Air Intake 2 in
B Exhaust Gas Vent 2 in
C Air Vent Connection
3
/4 in
D Heating Supply 1 in
E Heating Return 1 in
F Gas Connection
3
/4 in
G Condensate Outlet
1
/2 in
H Cold Water Inlet (DHW)
3
/4 in
I Hot Water Outlet (DHW)
3
/4 in
J Auto Feeder Inlet (Make-up Water)
1
/2 in
Overhead View
A
B
C
3.8” (97 mm)
4.3” (109 mm)
4.1” (105 mm)
9.7” (246 mm)
17.3” (440 mm)
Supply Connections
14.6” (370 mm)
2.6” (67 mm)
9.7” (247 mm)
5.2” (131 mm)
D
J E
17.3” (440 mm)
8.5” (215 mm)
10.6“ (269 mm)
3.3” (85 mm)
5.4” (136.6 mm)
2” (53 mm)
3.4” (87 mm)
I H
F
G
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4.2 Dip Switch 2 (8 switch unit)
The DIP SW 2 on the circuit board configures the gas type, temperature control modes, 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 Comment
1 Gas Type
Natural Gas 1-OFF
Refer to Table 1 in “4.4 Gas & High Altitude Conversion” on page 25
Propane Gas 1-ON
2 & 3 High Altitude
0-1,999 ft (0-609 m)
2-OFF, 3-OFF
2,000-5,399 ft (610-1,645 m)
2-ON, 3-OFF
5,400-7,699 ft (1,646-2,346 m)
2-OFF, 3-ON
7,700-10,100 ft (2,347-3,078 m)
2-ON, 3-ON
4 Well Pump
Used 4-ON -
Unused 4-OFF -
5 & 6 Country US/Canada
5-OFF, 6-OFF
-
7
Space Heating Thermostat
Used 7-OFF -
Unused 7-ON -
8
Exhaust Temperature Control
Used 8-OFF -
Unused 8-ON -
CAUTION
Do not remove the front cover unless the power to the boiler is turned off or disconnected. Failure to do so may
result in electric shock.
The boiler has 2 sets of DIP switches on the main circuit board (PCB). DIP switches are used to control the functionality of the boiler. Set the DIP switches appropriately, based on the installation environment.
4.1 DIP Switch 1 (6 switch unit)
The DIP SW 1 on the circuit board configures the operation status and model/capacity settings.
1 2 3 4 5 6
O N
O N
1 2 3 4 5 6 7 8
Switch Function Setting
1 & 2
Operation Status
Normal Operation 1-OFF, 2-OFF
2-stage MAX 1-ON, 2-OFF
1-stage MIN 1-OFF, 2-ON
1-stage MAX 1-ON, 2-ON
3 & 4 Reserved - -
5 & 6 Model
NFC-200 5-OFF, 6-OFF
NFC-175 5-ON, 6-OFF
4. System Details
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Note
When PCB DIP switch 2 #8 is set to On, ensure that CPVC, polypropylene, or stainless steel is used for exhaust venting.
This unit may be installed at elevations up to 10,100 ft (3,078 m) for use with natural gas and propane. To use the unit at a specific altitude, the DIP switches should be set as described above.
High Altitude: Above 2,000 ft (610 m), the unit will de-rate by 3% for each 1,000 ft (305 m) of altitude gain.
For NG, if you install the unit at above 5,400 ft (1,646 m), it is required to change the Gas Orifice for high altitude. Be careful not to confuse it with the LP Gas Orifice. Refer to “4.4 Gas & High Altitude Conversion” on page 25 for details.
Common vent installations for use with natural gas and propane are only approved for up to 4,500 ft.
CAUTION
Ensure that the High Altitude setting reflects the actual location of the boiler. If not, it may cause personal injury or malfunction of the boiler.
4.3 Measuring the Inlet Gas Pressure
WARNING
The boiler cannot function properly without sufficient inlet gas pressure. Measuring the inlet gas pressure should be performed by a licensed professional only.
The inlet gas pressure must be maintained between 3.5 in and
10.5 in WC for natural gas and between 8.0 in and 13.5 in WC for liquefied propane.
The appliance and its individual shutoff valve must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures in excess of
1
/2
psi (3.5 kPa).
The appliance must be isolated from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than
1
/2 psi (3.5 kPa).
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 panel, press the Back button ( ) and the Menu button ( ) simultaneously for 3 seconds, and then rotate the Command dial (
) to move to “7. Special
Operations”.
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3. Press the Command dial ( ) to enter special operation mode.
4. Rotate the Command dial ( ) to move to 7. SH 2nd MAX, and then press the Command dial (
) to select the operation
mode.
5. Press the Back button (
) twice to return to normal operation
mode.
6. Run space heating. The gas in the gas supply line will be purged.
7. Leave the boiler on until the boiler shuts down due to a lack of gas supply, and then turn off the boiler.
8. Unfasten the 4 latches (2 at the top and 2 at the bottom) to remove the front cover and gain access to the internal components.
9. Loosen the screws indicated in the figure below and connect a manometer to the pressure port. Reset the manometer to zero before use.
Digital pressure
manometer
10. Re-open the manual gas valve and check for leaks.
11. Activate multiple zones to ramp the boiler up to its maximum firing rate.
12. When the boiler reaches its maximum firing rate, check the inlet gas pressure reading on the manometer. The gas pressure must fall within the ranges specified on page 18.
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4.3.1 Gas Pipe Sizing Tables
The following tables are referenced from the 2012 National Fuel Gas Code and are for reference only. Please consult the gas pipe manufacturer for actual pipe capacities.
Maximum Natural Gas Delivery Capacity
In Cubic Feet (ft
3
) per Hour (0.60 Specific Gravity; 0.5 in WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures less than 6 in WC.
Pipe Size
Length (including fittings)
10 ft (3 m)
20 ft (6 m)
30 ft (9 m)
40 ft (12 m)
50 ft (15 m)
60 ft (18 m)
70 ft (21 m)
80 ft (24 m)
90 ft (27 m)
100 ft (30 m)
125 ft (38 m)
3
/4 in 360 247 199 170 151 137 126 117 110 104 92
1 in 678 466 374 320 284 257 237 220 207 195 173
1
1
/4 in 1,390 957 768 657 583 528 486 452 424 400 355
1
1
/2 in 2,090 1,430 1,150 985 873 791 728 677 635 600 532
2 in 4,020 2,760 2,220 1,900 1,680 1,520 1,400 1,300 1,220 1,160 1,020
2
1
/2 in 6,400 4,400 3,530 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 Cubic Feet (ft
3
) per Hour (0.60 Specific Gravity; 3.0 in WC Pressure Drop). Contact your gas supplier for BTU/ft3 ratings. Use 1,000 BTU/ft3 for
simplified calculations. This table is recommended for supply pressures of 6 in WC or greater.
Pipe Size
Length (including fittings)
10 ft (3 m)
20 ft (6 m)
30 ft (9 m)
40 ft (12 m)
50 ft (15 m)
60 ft (18 m)
70 ft (21 m)
80 ft (24 m)
90 ft (27 m)
100 ft (30 m)
125 ft (38 m)
1
/2 in 454 312 250 214 190 172 158 147 138 131 116
3
/4 in 949 652 524 448 397 360 331 308 289 273 242
1 in 1,787 1,228 986 844 748 678 624 580 544 514 456
1
1
/4 in 3,669 2,522 2,025 1,733 1,536 1,392 1,280 1,191 1,118 1,056 936
1
1
/2 in 5,497 3,778 3,034 2,597 2,302 2,085 1,919 1,785 1,675 1,582 1,402
2 in 10,588 7,277 5,844 5,001 4,433 4,016 3,695 3,437 3,225 3,046 2,700
2
1
/2 in 16,875 11,598 9,314 7,971 7,065 6,401 5,889 5,479 5,140 4,856 4,303
3 in 29,832 20,503 16,465 14,092 12,489 11,316 10,411 9,685 9,087 8,584 7,608
4 in 43,678 30,020 24,107 20,632 18,286 16,569 15,243 14,181 13,305 12,568 11,139
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Maximum Liquefied Propane Delivery Capacity
In Thousands of BTU/H (0.5 in WC pressure drop)
Pipe Size
Length (including fittings)
10 ft (3 m)
20 ft (6 m)
30 ft (9 m)
40 ft (12 m)
50 ft (15 m)
60 ft (18 m)
80 ft (24 m)
100 ft (30 m)
125 ft (38 m)
150 ft (45 m)
175 ft (53 m)
200 ft
(60 m)
250 ft (76 m)
1
/2 in 291 200 160 137 122 110 101 94 89 84 74 67 62
3
/4 in 608 418 336 287 255 231 212 197 185 175 155 140 129
1 in 1,150 787 632 541 480 434 400 372 349 330 292 265 243
1
1
/4 in 2,350 1,620 1,300 1,110 985 892 821 763 716 677 600 543 500
1
1
/2 in 3,520 2,420 1,940 1,660 1,480 1,340 1,230 1,140 1,070 1,010 899 814 749
2 in 6,790 4,660 3,750 3,210 2,840 2,570 2,370 2,200 2,070 1,950 1,730 1,570 1,440
NFC Service Manual 25
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Included Items:
Gas Orifice (Table 1)
Gas Pressure and Conversion Kit Number Labels
NFC-175/200 Orifice Identification
Gas Type NG LP
Altitude 0-5,399 ft 5,400-10,100 ft 0-10,100 ft
Orifice
NFC-200
NG
Ø6.3/Ø6.8
NFC-200
LP
Factory Installed For High altitude
For LP
Orifice
Size
Ø6.1/Ø6.6 Ø6.3/Ø6.8 Ø4.5/Ø4.9
Table 1. Orifice Size
WARNING
Be careful not to confuse the LP CONVERSION KIT and HIGH ALTITUDE CONVERSION KIT. Do NOT use the HIGH ALTITUDE CONVERSION KIT for NG when converting to LP gas.
Make sure that the conversion is completed with the proper orifice. If the installed orifice does not conform to the specifications in Table 1, incomplete combustion may occur, resulting in personal injury or property damage.
4.4 Gas & High Altitude Conversion
This boiler is configured for Natural Gas at the factory.
If conversion to Propane Gas is required by the boiler, use the LP CONVERSION KIT supplied with the boiler.
If the boiler is installed at a high altitude (above 5,400 ft) for NG, use the HIGH ALTITUDE CONVERSION KIT supplied with the boiler.
Note
For NG high altitude conversion, use the HIGH ALTITUDE CONVERSION KIT.
For LP high altitude conversion, use the LP CONVERSION KIT. Note that the Gas Orifice from the LP CONVERSION KIT covers the boiler’s installation at an altitude of 0 to 10,100 ft.
WARNING
This conversion kit must be installed by a qualified service agency* in accordance with Navien’s instructions and all applicable codes and requirements of the authority having jurisdiction. The information in these instructions must be followed to minimize the risk of fire or explosion or to prevent property damage, personal injury or death. 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 specified in the manufacturer’s instructions supplied with the kit.
* A qualified service agency is any individual, firm, corporation or company
which either in person or through a representative is engaged in and is responsible for the connection, utilization, repair or servicing of gas utilization equipment or accessories; who is experienced in such work, familiar with all precautions required, and has complied with all of the requirements of the authority having jurisdiction.
In Canada: The conversion shall be carried out in accordance with the requirements of the provincial authorities having jurisdiction and in accordance with the requirements of the CAN‐B149.1 and CAN1‐B149.2 Installation Code.
Tools Required:
Phillips Screwdriver
Flathead Screwdriver
5
/32 in or 4 mm Allen Wrench
Combustion Analyzer or Dual Port Manometer
Gas Leak Detector
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Procedure:
Note
The procedure below can be applied to both LP conversion and High Altitude conversion. Distinguish the kit supplied with the boiler before installing.
1. Turn off both gas and water supply to the boiler.
2. Unfasten the 4 latches (2 at the top and 2 at the bottom) to remove the front cover and gain access to the internal components. See Figure 1 for illustration of the front cover clamps.
Figure 1. NFC Series Front cover
3. Remove the front cover and place it in a safe location to prevent accidental damage.
4. With the internal components exposed, locate the gas inlet pipe and the gas valve, as shown in Figure 2.
Gas Valve
Gas Inlet Pipe
Figure 2. NFC Series Internal Components
5. Remove the clip at location A – the connection 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 assembly. Carefully remove the four screws using a Phillips-head screwdriver and pull the gas valve outlet adapter away from the fan assembly to access the gas orifice.
Location B: Remove 4 screws here
Location A: Remove the clip here
Figure 3. Detaching the Gas Valve Outlet Adapter
from the Gas Valve and Fan Motor Assembly
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7. Once the Gas Orifice is exposed, remove the two screws that hold the part in place. Remove the Gas Orifice from its housing and prepare the new Gas Orifice for the LP or High Altitude conversion for installation.
Remove 2 screws here
Figure 4. Access to Gas Orifice in Fan Assembly
WARNING
DO NOT adjust or attempt to measure gas valve outlet pressure. The gas valve is factory-set for the correct outlet pressure. This setting is suitable for natural gas and propane, requiring no field adjustment.
Attempting to alter or measure the gas valve outlet pressure could result in damage to the valve, causing potential severe personal injury, death or substantial property damage. Navien NFC boilers are shipped ready to fire natural gas ONLY.
O-ring
Packing
Gas Orifice
Figure 5. Exploded View of Gas Pipe Assembly
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8. Remove the Gas Orifice, ensure that the packing is properly seated inside the port, and then install the new Gas Orifice for use with LP gas. Ensure that the Orifice is properly seated on the packing inside the port before proceeding to the next step.
Packing
9. Replace the gas valve outlet adapter to its original position and use all screws to secure all connections.
Note
Do not overtighten as this may damage or crack the components.
10. Set the PCB DIP switch to change the gas type. For LP, set Dip Switch 2 #1 to ON. For NG, set DIP SW2 #1 to OFF.
WARNING
Ensure that you have turned off 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 Gas Type
Natural Gas 1-OFF
Refer to Table 1 on page
25.
Propane Gas 1-ON
2&3
High Altitude
0-1,999 ft (0-609m)
2-OFF, 3-OFF
2,000-5,399 ft (610-1,645m)
2-ON, 3-OFF
5,400-7,699 ft (1,646-2,346m)
2-OFF, 3-ON
7,700-10,100 ft (2,347-3,078m)
2-ON, 3-ON
When applying the Gas Orifice for high altitude, set the PCB DIP switches by altitude according to the table above.
Note
This unit may be installed at elevations up to 10,100 ft (3,078 m) for use with natural gas and propane. To use the unit at a specific altitude, the DIP Switches should be set as described above.
High Altitude: Above 2,000 ft (610 m), the unit will de­rate by 3% for each 1,000 ft (305 m) of altitude gain.
For NG, if you install the unit at above 5,400 ft (1,646 m), it is required to change the Gas Orifice for high altitude. Be careful not to confuse it with the Gas Orifice for LP.
Note that the Gas Orifice from the LP CONVERSION KIT covers the boiler’s installation at an altitude of 0 to 10,100 ft.
CAUTION
Ensure that the High Altitude setting reflects the actual location of the boiler. If not, it may cause personal injury or malfuction of the boiler.
DANGER
When conversion is required, be sure to set the PCB DIP switch 2 #1 according to the supply gas type.
For NG, use the Gas Orifice for high altitude when the boiler is installed at above 5,400 ft, and be careful not to confuse it with the Gas Orifice for LP.
For High Altitude conversion, check the DIP switches setting value by altitude before setting.
Failure to properly set the DIP switches could cause carbon monoxide poisoning, resulting in severe personal injury or death.
11. Turn on the gas and water supply to the boiler.
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Version 1.0
12. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer (recommended)
a. Loosen the screw, rotate the plate and remove the gasket
to access the emissions monitoring port as shown in Figure 6.
b. Insert the analyzer into the port (Figure 6).
Figure 6. Insert the Analyzer
The DIP SW 1 on the circuit board configures the operation status and model/capacity settings.
1 2 3 4 5 6
O N
O N
1 2 3 4 5 6 7 8
Switch Function Setting
1 & 2
Operation Status
Normal Operation 1-OFF, 2-OFF
2-stage MAX 1-ON, 2-OFF
1-stage MIN 1-OFF, 2-ON
1-stage MAX 1-ON, 2-ON
3 & 4 Reserved - -
5 & 6 Model
NFC-200 5-OFF, 6-OFF
NFC-175 5-ON, 6-OFF
Model Altitude Fuel
High fire Low fire
%CO
2
%CO
2
NFC-175 NFC-200
0-5,399 ft
NG 8.9 9.5
LP 10.2 10.8
5,400-10,100 ft
NG 8.5 9.5
LP 10.2 10.8
Table 2. CO
2
value
(CO
2
values must be within 0.5% of the values listed.)
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Option 2. Using Digital Manometer
a. Open the offset pressure port by loosening the screw two
turns as shown in Figure 8.
Digital pressure
manometer
Figure 8. Connect Digital Pressure Monometer
b. Connect a manometer to the offset pressure port. For dual
port manometers, use the positive pressure side.
Model Altitude Kit Part No. Gas Type Offset
NFC-175 NFC-200
0-5,399 ft NAC-N200
NG
-0.04 in
±0.01 in
5,400-10,100 ft NAC-NCH200
0-10,100 ft NAC-LC200 LP
-0.02 in
±0.01 in
Table 3. Offset value for low fire
c. Activate multiple zones and set the boiler to operate at
1-stage MIN mode.
Note
For operation mode selection, refer to “4.9.7 Setting the Special Operation Modes” on page
48.
Measure the CO
2
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 be adjusted. If adjustment is necessary, locate the set screw as shown in Figure 7. Using a
5
/32 in or 4 mm Allen wrench, turn
the set screw no more than
1
/4 turn clockwise to raise or
counterclockwise to lower the CO
2
value.
Figure 7. Set Screw Location
Note
The set screw is located behind the screw-on cover. This must be removed first.
d. Activate multiple zones and set the boiler to operate at
2-stage D. MAX mode (refer to “4.9.7 Setting the Special Operation Modes” on page 48). Measure the CO
2
value
at high fire. If the CO
2
values do not match Table 2 at high fire, do not
adjust the gas valve. Check for the proper Gas Orifice.
DANGER
Improper gas valve settings can cause severe personal injury, death or substantial property damage.
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