Navien NaviCirc Installation And Operation Manual page 20

2.1.2.1 Installing the Solenoid Valve (Optional)
A Navien external pump wire (#GXXX001319) is needed to
complete the solenoid valve installation. See the installation
guidelines below.
1. Make sure that the system power is off before proceeding with
the installation of the wiring.
2. Remove the front cover from the unit and remove the PCB by
removing the 2 attaching screws from the housing.
3. Use a 120 VAC (max 1.5 A) normally closed solenoid valve for
this application (a slow closing solenoid is recommended to
prevent water hammer).
4. Connect the external pump wire to the proper wires from the
solenoid valve.
5. Remove the 2 screws holding the PCB box in place and
remove the PCB box from the system.
Remove Screws here.
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