Navien NHB Series Installation & Operation Manual page 40

With 24VAC Connections
The C terminals are for optional connections with 24 V thermostat COMMON.
Note
If the DHW Tank is connected to the terminal, the T/S Zone 1 input is not available.
Pumps are connected through dry contact connections.
The rated output of the provided dry contacts are designed to be 5A/120V per each output.
40 Installing the System Piping
Boiler Pump
DHW Pump
Zone Pump 2
Use with dry
contacts only
Zone Pump 3
Pump Ground
Thermostat 1 Thermostat 2
DHW Aquastat
(Priority)
Thermostat 3