Navien NaviCirc Installation And Operation Manual page 28

3. Remove the 2 screws holding the PCB box in place and remove
the PCB box from the system.
4. Connect the external pump wiring connector to the connector
socket on the PCB (TB1).
5. Put the PCB box back in its original place and secure it using
the 2 mounting screws.
Remove Screws here.
TB1
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