Navien NFB-175 Mode D'emploi page 98

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
7. Once the Gas Orifice is exposed, remove the two screws that
hold the part in place. Remove the Gas Orifice from its housing
and prepare the new Gas Orifice for the LP conversion for
installation.
Figure 4. Access to Gas Orifice in Fan Assembly
98 Appendixes
Location B: Remove
4 screws here
Location A: Remove
the clip here
Remove 2
screws here
WARNING
DO NOT adjust or attempt to measure gas valve outlet
●
pressure. The gas valve is factory-set for the correct outlet
pressure. This setting is suitable for natural gas and propane,
requiring no field adjustment.
Attempting to alter or measure the gas valve outlet pressure
●
could result in damage to the valve, causing potential severe
personal injury, death or substantial property damage.
Navien NFB boilers are shipped ready to fire natural gas
ONLY.
O-ring
Figure 5. Exploded View of Gas Pipe Assembly
Packing
Gas Orifice