Navien NCB-180 Installation & Operation Manual page 61

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.
Remove two
2 screws here
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 NCB boilers are shipped ready to fire natural gas
ONLY.
60 Appendixes
Figure 5. Exploded View of Gas Pipe Assembly
DANGER
See Figure 5. Inspect the O-ring between the gas valve and
gas valve inlet adapter whenever they are disassembled.
The O-ring must be in good condition and must be installed.
Failure to comply will cause a gas leak, resulting in severe
personal injury or death.
Gas Orifice
O-ring