Navien NCB-180 Service Manual page 31

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.
Figure 5. Exploded view of Gas assembly
28 NCB Service Manual
12. Replace the old Orifice piece with the new part for use with
13. Replace the gas inlet pipe to its original position and use all
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
LP gas. Ensure that the Orifice is properly seated inside the
port before proceeding to the next step.
screws to secure all connections.
NOTE
Do not overtighten as this may damage or crack 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.
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