Navien NCB300-28K, Service Manual

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System Details 23
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 or substantial property
damage. Navien NCB300 boilers are shipped ready to fire
natural gas only.
Inner Packing
Outer Packing
Gas Gasket
Gas Orifice
Figure 5.1. Exploded View of Gas Pipe Assembly
(NCB300-28K)
10. Once the gas inlet pipe is detached from the gas valve, find
location B - the connection above the gas valve where it is
attached to the fan motor assembly. Carefully remove the
two screws by hand using a Phillips screwdriver and pull the
gas inlet pipe away from the fan assembly to access the gas
orifice.
Location B:
Remove two
screws here
Location A:
Loosen the hex
nut here
Figure 3. Detaching Gas Inlet Pipe from
Gas Valve and Fan Motor Assembly
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
screws here
Figure 4. Access to Gas Orifice in Fan Assembly
DANGER
A high voltage in the Fan Motor Assembly may cause an
electrical shock resulting in severe injury or death.