Navien NFC-175 Installation & Operation Manual page 104

Procedure:
The procedure below can be applied to both LP
Note
conversion and High Altitude conversion. Distinguish
the kit supplied with the boiler before installing.
1. Turn off both 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. NFC Series Front cover
3. Remove the front cover and place it in a safe location to
prevent accidental damage.
104 Appendixes
4. With the internal components exposed, locate the gas inlet
pipe and the gas valve, as shown in Figure 2.
Figure 2. NFC Series Internal Components
5. Remove the clip at location A – the connection above the gas
valve where it connects to the gas valve outlet adapter. See
Figure 3 for reference.
6. Find location B - the connection above the gas valve where it
is attached to the fan motor assembly. Carefully remove the
four screws using a Phillips-head screwdriver and pull the gas
valve outlet adapter away from the fan assembly to access the
gas orifice.
Figure 3. Detaching the Gas Valve Outlet Adapter
from the Gas Valve and Fan Motor Assembly
Gas Valve
Gas Inlet Pipe
Location B: Remove
4 screws here
Location A: Remove
the clip here