Navien NFC-250/175H Installation Manual page 130

Included Items:
Gas Orifice (Table 1)
●
Gas Pressure and Conversion Kit Number Labels
●
NFC-250/175H, 250/200H Orifice Identification
Gas
Natural Gas
Type
Altitude
0-5,399 ft
Orifice
GAS : NG
20052127A
4.8/7.90
Factory
Installed
Orifice
Ø4.8/Ø7.90
Size
Table 1. Orifice Size
WARNING
Be careful not to confuse the PROPANE
●
CONVERSION KIT and HIGH ALTITUDE
CONVERSION KIT. Do NOT use the HIGH
ALTITUDE CONVERSION KIT for NG when
converting to Propane gas.
Make sure that the conversion is completed
●
with the proper orifice. If the installed orifice
does not conform to the specifications in
Table 1, incomplete combustion may occur,
resulting in personal injury or property
damage.
Procedure:
The procedure below can be applied
Note
to both Propane conversion and High
Altitude conversion. Distinguish the kit
supplied with the boiler before installing.
1. Turn off both gas and water supply to the boiler.
130 Appendixes
Propane Gas
5,400-
0-10,100 ft
10,100 ft
GAS : NG(H) GAS : LP
20052133A 20052134A
3.90/6.00
5.05/8.4
For High
For Propane
altitude
Ø5.05/Ø8.4 Ø3.9/Ø6.0
2. Unfasten the 4 latches (2 at the top and 2 at the
bottom) to remove the front cover and gain
access to the internal components. See Figure 1
for illustration of the front cover clamps.
Figure 1. NFC-H Series Front cover
3. Remove the front cover and place it in a safe
location to prevent accidental damage.
4. With the internal components exposed, locate
the gas inlet pipe and the gas valve, as shown in
Figure 2.
Figure 2. NFC-H Series Internal Components
Gas Valve
Gas Inlet
Pipe