Navien NHB Series Installation & Operation Manual page 112

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
112 Appendixes
Packing
Gas Orifice
O-ring
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.
Figure 6. Orifice Identification
8. Remove the Gas Orifice, ensure that the packing is properly
seated inside the port, and then install the new Gas Orifice for
use at high altitudes. Ensure that the Orifice is properly seated
on the packing inside the port before proceeding to the next
step.
Packing
9. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
Do not overtighten as this may damage or crack
Note
the components.
DANGER
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.