Navien NaviCirc Installation And Operation Manual page 58

2.4.3.1 Accessing the NCB-H Terminal Strips
DANGER
Electric Shock Hazard
To prevent serious injury or death:
You must ensure that the boiler is disconnected from the
electrical supply before carrying out any servicing inside the
boiler and, particularly, on the electric terminal strips.
To access the PCB, carefully follow the steps below:
1. Turn off the power supply to the boiler.
2. Unfasten the 4 latches (2 at the top and 2 at the bottom)
to remove the front cover and gain access to the internal
components.
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