Navien NHB-055 Installation & Operation Manual page 88

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.
Packing
Gas Orifice
O-ring
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.
055LP
Figure 6. Orifice Identification
12. Remove the Gas Orifice, ensure that the packing is properly
seated inside the port, and then install the new Gas Orifice for
use with LP gas. Ensure that the Orifice is properly seated on
the packing inside the port before proceeding to the next step.
Packing
88 Appendixes
O-ring
055NG
13. 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.
14. Place the PCB assembly back on to the boiler and tighten the
three screws.
15. Check the labels carefully and then connect all the wires.
16. Set the front panel Dip Switch to change the gas type. For LP,
set Dip Switch 2 #2 to On. For NG, set DIP SW2 #2 to Off.
WARNING
Ensure that you have turned off the power to the boiler before
accessing the DIP switches.
ON
1 2 3 4 5 6
DANGER
When conversion is required, be sure to set the front panel
DIP switches according to the supply gas type.
Failure to properly set the DIP switches could cause carbon
monoxide poisoning, resulting in severe personal injury or
death.
ON
7 8 9 10 1 2
NG LP
ON ON
2 2