Navien NFC-175 Installation & Operation Manual page 105

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 or High Altitude
conversion for installation.
Figure 4. Access to Gas Orifice in Fan Assembly
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 NFC boilers are shipped ready to fire natural gas
ONLY.
Remove 2
screws here
Gas Orifice
O-ring
Figure 5. Exploded View of Gas Pipe Assembly
Packing
Appendixes 105