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Boiler gateway (fire tube combi/heating boiler) · BACnet points list
Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) BACnet points list
Updated 11 November 2026
The Navien Modbus/BACnet gateway reads an NFB-C boiler over Modbus RTU and presents it as a BACnet IP or BACnet MS/TP device (or Modbus TCP). The single-boiler profile gives on/off and enable commands, space-heat and DHW setpoints, temperatures, pump and thermostat states, error codes and run counters.
This page lists 66 BACnet objects for the Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) — 21 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Navien’s own free documentation, linked below.
- Manufacturer
- Navien
- Model
- NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)
- Equipment
- Boiler gateway (fire tube combi/heating boiler)
- Equipment type
- Boilers & water heaters
- BACnet objects
- 66 (21 writable)
- Transport
- BACnet IP, BACnet MS/TP
- Firmware
- Not stated
- Also known as
- NFB-C, NFB-301C, NFB-399C, Navien Modbus/BACnet Gateway, GXXX001932
Reference only, provided as-is: verify against Navien’s current documentation and the live device before use. Not official Navien information. Terms of use.
BMS integration notes: Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)
Enable the boiler and space heating from the BMS, write the supply and DHW setpoints, then read the operating status, temperatures and error codes. Error reset is an AV command.
Minimum points to map
The short list most integrators start with — enough to run the unit from a BMS. Map more as the job needs.
| Object | Name | Why | Access |
|---|---|---|---|
| AV 1 | Boiler On/Off command | Boiler on/off command | Write |
| BV 1 | SH operation on/off control | Space heating on/off | Write |
| AV 2 | SH supply setpoint setting | Space-heat supply water setpoint | Write |
| AV 4 | DHW setpoint setting | Domestic hot water setpoint | Write |
| AV 5 | Error reset command | Resets the boiler error | Write |
| AI 12 | Boiler Operation Status | Boiler operating status | Read |
| BI 1 | Burner operation state | Burner firing | Read |
| AI 4 | Supply temperature | Boiler supply water temperature | Read |
| AI 5 | Return temperature | Boiler return water temperature | Read |
| AI 1 | Main Error code | Active main error code | Read |
Enable & remote start
Boiler On/Off command (AV 1) and SH operation on/off control (BV 1) switch the boiler and space heating; DHW operation ON/OFF control (BV 4) does the same for hot water.
Network setup
- Gateway part number GXXX001932 (ports: RS-485 R1 to the boilers, Ethernet, RS-485 R2 for BACnet MS/TP).
- Boiler side: Modbus RTU at 9600 baud, 8 data bits, no parity, 1 stop bit; give each boiler a unique Node-ID (1-255).
- Device instance = Node_Offset + Node-ID; Node_Offset defaults to 50,000, so Node-ID 1 gives 50,001.
- Default gateway IP is 192.168.1.24 (Wi-Fi access point 192.168.50.1); pick the field protocol and the device profile in the Web Configurator.
- Set BACnet Virtual Server Nodes to Yes when more than one device is connected to the gateway.
Watch out for
- The guide gives no state or value tables; check codes such as Boiler Operation Status and error codes against the boiler manual.
- Setpoint and limit AVs are boiler settings; do not write them cyclically.
Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) BACnet objects
Type: AI, AO, AV, BI, BO, BV, MI/MO/MV (multi-state) · Access: Read read-only, Write writable, Command writable with a priority array.
Note: the source document has no read/write column, so access here is inferred from the object type (inputs read-only, values writable). Confirm on the live controller before writing.
| Description | States | |||||
|---|---|---|---|---|---|---|
| AImin | 1 | Main Error code | Read | |||
| AI | 2 | Sub Error code | Read | |||
| AI | 3 | Current Heat capacity | Read | |||
| AImin | 4 | Supply temperature | Read | |||
| AImin | 5 | Return temperature | Read | |||
| AI | 6 | System Supply temperature | Read | |||
| AI | 7 | System Return temperature | Read | |||
| AI | 8 | Water pressure | Read | |||
| AI | 9 | Exhaust temperature | Read | |||
| AI | 10 | DHW Tank temperature | Read | |||
| AI | 11 | Outdoor temperature | Read | |||
| AImin | 12 | Boiler Operation Status | Read | |||
| AI | 13 | Maximum Heat capacity | Read | |||
| AI | 14 | Total time of CH operation | Read | |||
| AI | 15 | Number of CH operation | Read | |||
| AI | 16 | Total time after installation | Read | |||
| AI | 27 | Maximum outdoor temperature status | Read | |||
| AI | 28 | Minimum outdoor temperature status | Read | |||
| AI | 29 | CH supply minimum temperature | Read | |||
| AI | 30 | CH supply maximum temperature | Read | |||
| AI | 31 | CH return minimum temperature | Read | |||
| AI | 32 | CH return maximum temperature | Read | |||
| AI | 33 | DHW minimum temperature | Read | |||
| AI | 34 | DHW maximum temperature | Read | |||
| AI | 35 | SH control method | Read | |||
| AI | 36 | DHW control method | Read | |||
| AI | 38 | Gas type | Read | |||
| AI | 41 | Current amount of gas | Read | |||
| AI | 42 | Total amount of gas | Read | |||
| AVmin | 1 | Boiler On/Off command | Write | |||
| AVmin | 2 | SH supply setpoint setting | Write | |||
| AV | 3 | SH return setpoint setting | Write | |||
| AVmin | 4 | DHW setpoint setting | Write | |||
| AVmin | 5 | Error reset command | Write | |||
| AV | 7 | Boiler setpoint in DHW operation | Write | |||
| AV | 9 | Outdoor reset curve heatload setting | Write | |||
| AV | 10 | Maximum outdoor temperature setting | Write | |||
| AV | 11 | Minimum outdoor temperature setting | Write | |||
| AV | 12 | WWSD temperature setting | Write | |||
| AV | 13 | WWSD On differential setting | Write | |||
| AV | 14 | Boost interval time setting | Write | |||
| AV | 15 | Cascade Initial op units setting | Write | |||
| AV | 16 | CH supply min temperature setting | Write | |||
| AV | 17 | CH supply max temperature setting | Write | |||
| AV | 18 | CH return min temperature setting | Write | |||
| AV | 19 | CH return max temperature setting | Write | |||
| BImin | 1 | Burner operation state | Read | |||
| BI | 2 | SH operation state | Read | |||
| BI | 4 | DHW tank mode operation state | Read | |||
| BI | 5 | Error state | Read | |||
| BI | 7 | Boiler enable status | Read | |||
| BI | 8 | Boiler pump Operation Status | Read | |||
| BI | 9 | DHW/Zone1 pump Operation Status | Read | |||
| BI | 10 | Zone2 pump status Operation Status | Read | |||
| BI | 11 | System/Zone3 pump Operation Status | Read | |||
| BI | 12 | SH1 Thermostat input Status | Read | |||
| BI | 13 | SH2 Thermostat input Status | Read | |||
| BI | 14 | SH3 Thermostat input Status | Read | |||
| BI | 15 | DHW call signal | Read | |||
| BI | 16 | DHW Thermostat input Status | Read | |||
| BI | 17 | LWCO input status | Read | |||
| BI | 24 | Frozen protection mode | Read | |||
| BVmin | 1 | SH operation on/off control | Write | |||
| BV | 2 | Outdoor reset curve usage enable | Write | |||
| BV | 3 | WWSD enable | Write | |||
| BV | 4 | DHW operation ON/OFF control | Write |
No points match these filters.
Object ID lookup: Navien NFB-C Single Boiler Gateway point IDs by name
AI1Main Error codeAI2Sub Error codeAI3Current Heat capacityAI4Supply temperatureAI5Return temperatureAI6System Supply temperatureAI7System Return temperatureAI8Water pressureAI9Exhaust temperatureAI10DHW Tank temperatureAI11Outdoor temperatureAI12Boiler Operation StatusAI13Maximum Heat capacityAI14Total time of CH operationAI15Number of CH operationAI16Total time after installationAI27Maximum outdoor temperature statusAI28Minimum outdoor temperature statusAI29CH supply minimum temperatureAI30CH supply maximum temperatureAI31CH return minimum temperatureAI32CH return maximum temperatureAI33DHW minimum temperatureAI34DHW maximum temperatureAI35SH control methodAI36DHW control methodAI38Gas typeAI41Current amount of gasAI42Total amount of gasAV1Boiler On/Off commandAV2SH supply setpoint settingAV3SH return setpoint settingAV4DHW setpoint settingAV5Error reset commandAV7Boiler setpoint in DHW operationAV9Outdoor reset curve heatload settingAV10Maximum outdoor temperature settingAV11Minimum outdoor temperature settingAV12WWSD temperature settingAV13WWSD On differential settingAV14Boost interval time settingAV15Cascade Initial op units settingAV16CH supply min temperature settingAV17CH supply max temperature settingAV18CH return min temperature settingAV19CH return max temperature settingBI1Burner operation stateBI2SH operation stateBI4DHW tank mode operation stateBI5Error stateBI7Boiler enable statusBI8Boiler pump Operation StatusBI9DHW/Zone1 pump Operation StatusBI10Zone2 pump status Operation StatusBI11System/Zone3 pump Operation StatusBI12SH1 Thermostat input StatusBI13SH2 Thermostat input StatusBI14SH3 Thermostat input StatusBI15DHW call signalBI16DHW Thermostat input StatusBI17LWCO input statusBI24Frozen protection modeBV1SH operation on/off controlBV2Outdoor reset curve usage enableBV3WWSD enableBV4DHW operation ON/OFF control
Integration notes
- From Appendix C.1, NFB-C Single Boiler Modbus RTU mappings to BACnet/IP and BACnet MS/TP (guide page 25).
- The table gives only point name, object type and instance: no units, ranges or read/write column. Access here is inferred: AV and BV objects are treated as writable commands and settings, AI and BI as read-only.
Check it against the live device. A points list tells you what the controller can expose; the unit in front of you may differ by firmware or installed options. This list is provided as-is for reference only and may contain mistakes — confirming it before you write, map or commission anything is up to you (terms). Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) and exports what it actually has to Excel — free. New to BACnet? Start with what a BACnet points list is and what the object types mean.
Questions about the Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)
How many BACnet points does the Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) have?
This list has 66 BACnet objects: 29 analog inputs, 17 analog values, 16 binary inputs, 4 binary values. The exact set on a given unit depends on its firmware, installed options and configuration.
Which Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) BACnet points are writable?
21 of the 66 objects accept a write. Points marked Command have a priority array: a write holds until it is released, so release it back to automatic when you are done. The source has no read/write column, so this is inferred from object type.
Where is the official Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway) BACnet documentation?
The source is Modbus/BACnet Gateway Start-up Guide (Installation & Operation Manual) for interfacing Navien products to building automation systems, revision Effective October 1, 2019, published free by Navien at https://www.navieninc.com/downloads/modbus-bacnet-installation-and-operation-manual-en/download.
What are the minimum BACnet points to integrate the Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)?
Start with AV 1 Boiler On/Off command (Boiler on/off command); BV 1 SH operation on/off control (Space heating on/off); AV 2 SH supply setpoint setting (Space-heat supply water setpoint); AV 4 DHW setpoint setting (Domestic hot water setpoint); AV 5 Error reset command (Resets the boiler error); AI 12 Boiler Operation Status (Boiler operating status); BI 1 Burner operation state (Burner firing); AI 4 Supply temperature (Boiler supply water temperature); AI 5 Return temperature (Boiler return water temperature); AI 1 Main Error code (Active main error code).
How do I enable BMS control of the Navien NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)?
Boiler On/Off command (AV 1) and SH operation on/off control (BV 1) switch the boiler and space heating; DHW operation ON/OFF control (BV 4) does the same for hot water.
How do I check these points on the real NFB-C Fire Tube Boiler - Single Boiler (Modbus/BACnet Gateway)?
Scan the network with a BACnet IP browser such as Easy BACnet, open the device and compare its object list with this table. Anything missing is usually an option that isn't installed or a point that is disabled in the controller's configuration.
More Navien BACnet points lists
Source: Modbus/BACnet Gateway Start-up Guide (Installation & Operation Manual) for interfacing Navien products to building automation systems · rev. Effective October 1, 2019. Object names, instances and units are reproduced as published; descriptions are our own.