Navien NCB-24LSWE, Service Manual

Page: 27 / 144

NCB Service Manual 25
Version 1.0
9. Loosen the hex nut at location A - the connection
above the gas valve where it connects to the pipe
(refer to Figure 3-1 and Figure 3-2). When the hex nut
is loosened, carefully separate the pipe from the gas
valve.
10. Detach the gas inlet pipe from the gas valve and
locate B - the connection above the gas valve where
it is attached to the fan motor assembly. Carefully
remove the two screws (four screws for NCB-
40LSWE) using a Phillips screwdriver. Then, pull the
gas inlet pipe out from the fan assembly to access
the gas orifice.
Figure 3-1. Detaching Gas Inlet Pipe from
Gas Valve and Fan Motor Assembly (NCB-24/28/34LSWE)
Figure 3-2. Detaching Gas Inlet Pipe from
Gas Valve and Fan Motor Assembly (NCB-40LSWE)
When the gas orifice is exposed, remove the two screws
that hold it in place. Remove the orifice from its housing
and prepare the new LP orifice for installation.
Figure 4-1. Access to Gas Orifice in Fan Assembly
(NCB-24/28/34LSWE)
Figure 4-2. Access to the gas orifice in fan assembly
(NCB-40LSWE)
WARNING

DO NOT adjust or attempt to
measure the outgoing gas pressure.
The gas valve is factory-set for the
correct outlet pressure. This setting
is suitable for natural gas and
propane and does not require field
adjustment.

Attempting to adjust or measure
the gas valve outlet pressure
could result in damage to the
valve or other property, serious
personal injury, o r death. Navien
NCB LSWE boilers are shipped
configured for natural gas
installations ONLY.