20 NHB Service Manual
Version 1.0
Set of PCB DIP Switch 2 (8 switch unit)
The DIP SW 2 on the circuit board configures the temperature
control modes, country, and enables or disables the space heating
thermostat.
1 2 3 4 5 6
ON
1 2 3
4
5
6
7 8
ON
Switch
Function
Setting
1 & 2
Space Heating
Temperature
Control
Supply Temperature
1-OFF, 2-OFF
Return Temperature
1-ON, 2-OFF
System Supply
Temperature(with
optional sensor)
1-OFF, 2-ON
System Return
Temperature(with
optional sensor)
1-ON, 2-ON
3
DHW Tank
Temperature
Control
DHW Supply
Temperature
3-OFF
DHW System Supply
Temperature(with
optional sensor)
3-ON
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
piping is used for exhaust venting.
4.1.2 Front Panel DIP Switches
Set of Front Panel DIP Switch 1 (10 switch unit)
The DIP SW 1 on the front panel configures the temperature unit
and high altitude settings.
Before changing the settings, lift the rubber cover to access the
front panel DIP switches.
1
2
3
4
5
6 7 8
9 10
1 2
ON
ON
Switch
Function
Setting
2
Temperature
Unit
°F (Fahrenheit)
2-ON
°C (Celsius)
2-OFF
4 & 5
High
Altitude*
0-1,999 ft. (0-609 m) 4-OFF, 5-OFF
2,000-5,399 ft.
(610-1,645 m)
4-ON, 5-OFF
5,400-7,699 ft.
(1,646-2,346 m)
4-OFF, 5-ON
7,700-10,100 ft.
(2,347-3,078 m)
4-ON, 5-ON
* At altitudes above 2,000 ft. (610 m) the boiler’s rating will reduce by 4 %
for each 1,000ft (305 m) gain in altitude.
NOTE
This boiler may be installed at altitudes of 10,100 ft. (3,078 m)
for use with Natural Gas and 4,500 ft. (1,370 m) for use with
Propane. To use the boiler at a specific altitude, set the DIP
switches as detailed in the table above.
Summary of Contents for NHB-055
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