Navien NHB H Series Installation And Operation Manual page 122

Procedure:
The procedure below can be applied
Note
to both Propane conversion and High
Altitude conversion. Distinguish the kit
supplied with the boiler before installing.
1. Turn off the power, gas, and water 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. See Figure 1
for illustration of the front cover clamps.
Figure 1. NHB-H Series Front cover
3. Remove the front cover and place it in a safe
location to prevent accidental damage.
4. Label all the wires on the PCB.
5. Disconnect all the wires.
6. Loosen the four screws indicated in the figure.
122 Appendixes
7. Remove the PCB assembly.
8. With the internal components exposed, locate
the gas inlet pipe and the gas valve in the
middle of the unit, as shown in Figure 2.
Figure 2. NHB-H Series Internal Components
9. Use a Phillips screwdriver to remove the two
screws at location A - the connection below
the gas valve where it connects to the pipe.
See Figure 3 for reference. Once the screws are
removed, carefully separate the pipe from the
gas valve.
Gas Inlet Pipe
Gas Valve