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70 Setting the DIP Switches
6.2 Dip Switch 2 (Set of 8 Switches)
The DIP SW2 (Set of 8 Switches) on the circuit board configures the gas type, altitude, temperature control
modes, country, and enables or disables the space heating thermostat.
1 2 3 4 5 6
O
N
O
N
1 2
3
4
5 6 7 8
Switch
Function
Setting
Comment
1
Gas Type
Natural Gas
1-OFF
Refer to Table 1 in
Propane Gas
1-ON
2 & 3
High Altitude
0-1,999 ft (0-609 m)
2-OFF, 3-OFF
2,000-5,399 ft (610-1,645 m)
2-ON, 3-OFF
5,400-7,699 ft (1,646-2,346 m)
2-OFF, 3-ON
7,700-10,100 ft (2,347-3,078 m)
2-ON, 3-ON
4
Reserved
-
-
-
5 & 6
Country
US/Canada
5-OFF, 6-OFF
-
7
Space Heating
Thermostat
Used
7-OFF
-
Unused
7-ON
-
8
Exhaust
Temperature Control
Used
8-OFF
-
Unused
8-ON
-
Note
●
When PCB DIP switch 2 #8 is set to On, ensure that CPVC or polypropylene piping is used for exhaust
venting.
●
This unit may be installed at elevations up to 10,100 ft (3,078 m) for use with natural gas and
propane. To use the unit at a specific altitude, the DIP switches should be set as described above.
●
High Altitude: Above 2,000 ft (610 m), the unit will de-rate by 3% for each 1,000 ft (305 m) of altitude
gain.
●
For NG, if you install the unit at above 5,400 ft (1,646 m), it is required to change the Gas Orifice
for high altitude. Be careful not to confuse it with the Gas Orifice for LP. Refer to “12.1 Gas & High
Altitude Conversion” on page 117 for details.
●
Common vent installations for use with natural gas and propane are only approved for up to 4,500 ft.
CAUTION
Ensure that the High Altitude setting reflects the actual location of the boiler. If not, it may cause personal
injury or malfunction of the boiler.
Summary of Contents for NFB-175H
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