Navien NHB-055, Service Manual

Page: 27 / 147

NHB Service Manual 27 Version 1.0
11. 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 6. 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 NHB boilers are shipped ready to fire natural gas
ONLY.
O-ring
O-ring
Gas Orifice
Figure 7. Exploded view of Gas assembly
DANGER
See Figure 7. 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.
055LP 055NG
Figure 8. Orifice identification
12. Replace the old Orifice piece with the new part for use with LP
gas. Ensure that the Orifice is properly seated inside the port
before proceeding to the next step.
13. Replace the gas inlet pipe to its original position and use all
screws to secure all connections.
NOTE
Do not over tighten 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.