Easy BACnetDual-heat-exchanger condensing boiler controller · BACnet points list
Lochinvar SYNC BACnet points list
Updated 28 October 2026
The SYNC boiler has two heat exchangers in one cabinet, so its BACnet MS/TP map repeats the flame, switch, temperature and status points for unit 1 and unit 2. Access is through Lochinvar's Modbus/BACnet communication board.
This page lists 62 BACnet objects for the Lochinvar SYNC — 9 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Lochinvar’s own free documentation, linked below.
- Manufacturer
- Lochinvar
- Model
- SYNC
- Equipment
- Dual-heat-exchanger condensing boiler controller
- Equipment type
- Boilers & water heaters
- BACnet objects
- 62 (9 writable)
- Transport
- BACnet MS/TP
- Firmware
- Not stated
- Default device instance
- 630000 + MAC address (base is model dependent and can be changed)
- Also known as
- SYNC 1.0, SYNC 1.3, SYNC 1.5, SYNC-MODB
BMS integration notes: Lochinvar SYNC
Pick the BMS control mode at the boiler, then write AV 0 Configuration so the unit knows which values the BAS will supply. After that the BAS sends an enable, a rate command (AV 2), or both, and keeps rewriting them. Status, temperatures and the status, blocking and lockout codes can be read without taking control.
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 0 | Configuration | Bitmask of BAS-supplied inputs; resend before commands | Write |
| BV 0 | Boiler Enable | Enable / call for heat from the BAS | Write |
| AV 2 | 0-10 Volt Input / Rate Command / Setpoint Command | Rate command: firing % or setpoint, per BMS Type | Write |
| AI 13 | Unit 1 Status Code | What heat exchanger 1 is doing; 40 = lockout | Read |
| AI 22 | Unit 2 Status Code | What heat exchanger 2 is doing; 40 = lockout | Read |
| AI 8 | Outlet Temperature 1 | Outlet temperature, heat exchanger 1 | Read |
| AI 17 | Outlet Temperature 2 | Outlet temperature, heat exchanger 2 | Read |
| AI 15 | Unit 1 Lockout Code | Lockout cause, heat exchanger 1; valid only at status 40 | Read |
| AI 24 | Unit 2 Lockout Code | Lockout cause, heat exchanger 2; valid only at status 40 | Read |
Enable & remote start
Set Demand Configuration 4, 5 or 6 under Main > Setup > Service/Setup > Demand Config. 4: local setpoints plus BV 0 enable. 5: enable plus AV 2 rate command. 6: AV 2 modulation % alone. Set the matching AV 0 bits first. AV 2 means firing % or temperature setpoint depending on the BMS Type setting (Power or Setpoint); as a setpoint it is scaled like a 0-10 V signal between the BMS temperatures at low and high input.
Heartbeat & communication loss
If BAS-written temperatures or commands stop arriving, the unit reverts to its own readings and controls. The timeout is set under Main > Setup > BMS > Modbus / BACnet Timeout; the manual gives 5-120 s with a 10 s default in one place and 0-120 s in another. Every write resets it, and Lochinvar recommends the shortest value. Commands without temperatures must be refreshed at least every 4 minutes.
Sensors & values from the BMS
Set the AV 0 bits for the values the BAS will supply, then write them to the analog values: AV 3 tank setpoint, AV 4 tank temperature, AV 5 outdoor temperature, AV 6 system supply temperature. Values are in °C. Temperatures must be rewritten every few seconds or the unit returns to its own sensors.
Network setup
- MAC address from dip switches 1-8 (master only, so 0-127); baud from switches 9-10: 9600, 19200, 38400 or 76800.
- Device instance = base 630000 + MAC address; the base can be changed.
Watch out for
- The manual says to resend the AV 0 configuration bits before each command.
- In a cascade only the Leader needs the BACnet board for control; it then reports cascade totals only, so fit a board to every unit to see each one.
- Without BMS mode active the board is monitor-only: the read-only points can be polled while the unit runs on its own controls.
- Status, temperature and code points come in pairs for heat exchanger 1 and 2.
Lochinvar SYNC 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.
| Description | States | |||||
|---|---|---|---|---|---|---|
| BVmin | 0 | Boiler Enable | BAS enable command for the appliance | Write | ||
| BV | 4 | Tank Thermostat | Tank / DHW thermostat call | Write | ||
| BI | 0 | Manual Reset High Limit 1 | Safety / proving switch status | Read | ||
| BI | 1 | Flow Switch 1 | Safety / proving switch status | Read | ||
| BI | 2 | Gas Pressure Switch 1 | Safety / proving switch status | Read | ||
| BI | 3 | Louver Proving Switch 1 | Safety / proving switch status | Read | ||
| BI | 4 | Flap Valve 1 | Safety / proving switch status | Read | ||
| BI | 5 | Blocked Drain Switch 1 | Safety / proving switch status | Read | ||
| BI | 6 | Auto Reset High Limit 1 | Safety / proving switch status | Read | ||
| BI | 7 | Flame 1 | Flame status | Read | ||
| BI | 8 | Enable | Enable input status | Read | ||
| BI | 9 | Tank Thermostat | Tank / DHW thermostat call | Read | ||
| BI | 16 | Manual Reset High Limit 2 | Safety / proving switch status | Read | ||
| BI | 17 | Flow Switch 2 | Safety / proving switch status | Read | ||
| BI | 18 | Gas Pressure Switch 2 | Safety / proving switch status | Read | ||
| BI | 19 | Louver Proving Switch 2 | Safety / proving switch status | Read | ||
| BI | 20 | Flap Valve 2 | Safety / proving switch status | Read | ||
| BI | 21 | Blocked Drain Switch 2 | Safety / proving switch status | Read | ||
| BI | 22 | Flame 2 | Flame status | Read | ||
| BI | 32 | Run-time Contacts 1 | Output or relay status | Read | ||
| BI | 33 | Alarm Contacts 1 | Output or relay status | Read | ||
| BI | 34 | Boiler Pump 1 | Output or relay status | Read | ||
| BI | 35 | DHW Pump 1 | Output or relay status | Read | ||
| BI | 37 | Gas Valve 1 | Output or relay status | Read | ||
| BI | 38 | System Pump | Output or relay status | Read | ||
| BI | 40 | Run-time Contacts 2 | Output or relay status | Read | ||
| BI | 41 | Alarm Contacts 2 | Output or relay status | Read | ||
| BI | 42 | Boiler Pump 2 | Output or relay status | Read | ||
| BI | 43 | DHW Pump 2 | Output or relay status | Read | ||
| BI | 45 | Gas Valve 2 | Output or relay status | Read | ||
| BI | 48 | Fan 1 Power | Output or relay status | Read | ||
| BI | 49 | Fan 2 Power | Output or relay status | Read | ||
| AI | 0 | Binary Inputs 0 - 15 | Packed word of binary inputs 0-15 | Read | ||
| AI | 1 | Binary Inputs 16 - 31 | Packed word of binary inputs 16-31 | Read | ||
| AI | 2 | Binary Inputs 32 - 47 | Packed word of binary inputs 32-47 | Read | ||
| AI | 3 | System / Cascade Setpoint | Setpoint value | °C | Read | |
| AI | 5 | Cascade Total Power | Total cascade firing capacity | % | Read | |
| AI | 6 | Cascade Current Power | Current cascade firing rate | % | Read | |
| AI | 7 | Outlet Setpoint 1 | Setpoint value | °C | Read | |
| AImin | 8 | Outlet Temperature 1 | Temperature reading | °C | Read | |
| AI | 9 | Inlet Temperature 1 | Temperature reading | °C | Read | |
| AI | 10 | Flue Temperature 1 | Temperature reading | °C | Read | |
| AI | 11 | Firing Rate 1 | Burner firing rate | % | Read | |
| AImin | 13 | Unit 1 Status Code | Current operating status code | Read | ||
| AI | 14 | Unit 1 Blocking Code | Active blocking (soft lockout) code | Read | ||
| AImin | 15 | Unit 1 Lockout Code | Active lockout code | Read | ||
| AI | 16 | Outlet Setpoint 2 | Setpoint value | °C | Read | |
| AImin | 17 | Outlet Temperature 2 | Temperature reading | °C | Read | |
| AI | 18 | Inlet Temperature 2 | Temperature reading | °C | Read | |
| AI | 19 | Flue Temperature 2 | Temperature reading | °C | Read | |
| AI | 20 | Firing Rate 2 | Burner firing rate | % | Read | |
| AImin | 22 | Unit 2 Status Code | Current operating status code | Read | ||
| AI | 23 | Unit 2 Blocking Code | Active blocking (soft lockout) code | Read | ||
| AImin | 24 | Unit 2 Lockout Code | Active lockout code | Read | ||
| AI | 25 | Binary Inputs 48 - 63 | Packed word of binary inputs 48-63 | Read | ||
| AVmin | 0 | Configuration | Bitmask selecting which values the BAS supplies | Write | ||
| AV | 1 | Binary Values | Packed word of the binary value commands | Write | ||
| AVmin | 2 | 0-10 Volt Input / Rate Command / Setpoint Command | BAS rate or setpoint command (0-100%) | % | Write | |
| AV | 3 | Tank Setpoint | Setpoint value | °C | Write | |
| AV | 4 | Tank Temperature | Temperature reading | °C | Write | |
| AV | 5 | Outdoor Temperature | Temperature reading | °C | Write | |
| AV | 6 | System Supply Temperature | Temperature reading | °C | Write |
No points match these filters.
Integration notes
- BACnet needs the optional Lochinvar Modbus/BACnet communication board; address and baud rate are set on its dip switches.
- The BACnet board is an MS/TP master only, so MAC addresses 0-127 are usable.
- AV 0 (Configuration) is a bitmask: set a bit to 1 to make the appliance use the BAS-written value instead of its own input.
- BAS-supplied temperatures must be rewritten every few seconds and other commands at least every 4 minutes, or the unit reverts to local control.
- Temperatures are in °C on the bus.
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. Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the SYNC 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 Lochinvar SYNC
How many BACnet points does the Lochinvar SYNC have?
This list has 62 BACnet objects: 23 analog inputs, 7 analog values, 30 binary inputs, 2 binary values. The exact set on a given unit depends on its firmware, installed options and configuration.
Which Lochinvar SYNC BACnet points are writable?
9 of the 62 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.
Where is the official Lochinvar SYNC BACnet documentation?
The source is Modbus and BACnet Communication Instructions (SYNC 1.0 - 1.3 - 1.5) (SYNC-MODB_100161723_2000017706), revision Rev L, 05/17, published free by Lochinvar at https://assets.lochinvar.com/damroot/Original/10014/594260SYNC-MODB_100161723_2000017706__REV%20L_BACNET.pdf.
What are the minimum BACnet points to integrate the Lochinvar SYNC?
Start with AV 0 Configuration (Bitmask of BAS-supplied inputs; resend before commands); BV 0 Boiler Enable (Enable / call for heat from the BAS); AV 2 0-10 Volt Input / Rate Command / Setpoint Command (Rate command: firing % or setpoint, per BMS Type); AI 13 Unit 1 Status Code (What heat exchanger 1 is doing; 40 = lockout); AI 22 Unit 2 Status Code (What heat exchanger 2 is doing; 40 = lockout); AI 8 Outlet Temperature 1 (Outlet temperature, heat exchanger 1); AI 17 Outlet Temperature 2 (Outlet temperature, heat exchanger 2); AI 15 Unit 1 Lockout Code (Lockout cause, heat exchanger 1; valid only at status 40); AI 24 Unit 2 Lockout Code (Lockout cause, heat exchanger 2; valid only at status 40).
How do I enable BMS control of the Lochinvar SYNC?
Set Demand Configuration 4, 5 or 6 under Main > Setup > Service/Setup > Demand Config. 4: local setpoints plus BV 0 enable. 5: enable plus AV 2 rate command. 6: AV 2 modulation % alone. Set the matching AV 0 bits first. AV 2 means firing % or temperature setpoint depending on the BMS Type setting (Power or Setpoint); as a setpoint it is scaled like a 0-10 V signal between the BMS temperatures at low and high input.
Does the Lochinvar SYNC need a BACnet heartbeat or have a communication timeout?
If BAS-written temperatures or commands stop arriving, the unit reverts to its own readings and controls. The timeout is set under Main > Setup > BMS > Modbus / BACnet Timeout; the manual gives 5-120 s with a 10 s default in one place and 0-120 s in another. Every write resets it, and Lochinvar recommends the shortest value. Commands without temperatures must be refreshed at least every 4 minutes.
Can the BMS supply sensor values to the Lochinvar SYNC?
Set the AV 0 bits for the values the BAS will supply, then write them to the analog values: AV 3 tank setpoint, AV 4 tank temperature, AV 5 outdoor temperature, AV 6 system supply temperature. Values are in °C. Temperatures must be rewritten every few seconds or the unit returns to its own sensors.
How do I check these points on the real SYNC?
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 Lochinvar BACnet points lists
- Commercial condensing water heater controller
Lochinvar Armor 1250-4000 water heater (SMART SYSTEM)
Lochinvar Armor volume water heaters, models 1250-4000, Series 100 and 101, with the SMART SYSTEM control and the Modbus/BACnet communication board.
Also known as: Armor, Armor 1250, Armor 4000, AWH, Armor Series 100, Armor Series 101, SMART SYSTEM, MTR-01, 100305786 - Condensing boiler controller
Lochinvar Crest
Crest FB/OF 751-6001 and FCB 1000-6000 condensing boilers (the manual uses the same map for Hellcat).
Also known as: Crest FB, Crest OF, Crest FCB, Hellcat - Condensing boiler / water heater controller
Lochinvar Knight / Armor (SMART TOUCH)
Knight, Knight XL, Armor, Wall Mount, Wall Hung, AQUAS, FTXL and Shield boilers and water heaters with the SMART TOUCH control.
Also known as: Knight XL, Outdoor Knight, Armor, Wall Mount, Wall Hung, AQUAS, FTXL, Shield, MODB-I-O - Commercial water heater controller
Lochinvar Regent
Regent IWH 500-1000 commercial gas water heaters.
Also known as: Regent IWH, IWH500-1000
Source: Modbus and BACnet Communication Instructions (SYNC 1.0 - 1.3 - 1.5) · SYNC-MODB_100161723_2000017706 · rev. Rev L, 05/17. Object names, instances and units are reproduced as published; descriptions are our own.