Navien NFB Series User Manual

105Appendixes
12.5 Outdoor Reset Control
The Outdoor Reset Control feature may be used to enhance energy
efficiency while maintaining optimal heating performance. With
the Outdoor Reset Control, the space heating temperature setting
automatically changes according to the outdoor temperature and
the current space heating system application (system load).
You can configure the Outdoor Reset Control settings on the front
panel. Refer to “11.3.3 Setting the Space Heating Operation” on
page 86 and “11.4.3 Setting the Operation Parameters“ on page
90.
Note
The Outdoor Reset Control feature requires installation
of an outdoor temperature sensor, and it only works
when the boiler is running in the normal operation
mode. It does not work when the boiler is running in
either the Minimum (MIN) or Maximum (MAX) mode, or
when the boiler’s front panel displays a fault.
45 40 35 30 25 20 15 10 5 0 -5 -10 -15 -20 -25
185
194
176
167
158
149
140
131
122
113
104
95
86
77
68
59
50
113 104 95 86 77 68 59 50 41 32 23 14 5 -4 -13
°F
°C
85
90
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
°F °C
Absolute
MAX
Absolute
MIN
Outdoor
High MIN
Outdoor
Low MIN
High Mass Radiant
Low Mass Radiant
Cast Iron Baseboard
Custom
Radiator
Finned Tube Baseboard
Fan Coil
Space Heating Temperature Setting for the
Outdoor Reset Control Feature
The following tables list the default space heating temperature
range by system heat load and the applicable outdoor
temperature ranges.
Outdoor Temperature Sensor Installation Guidelines
Heat Load
Supply Set Point
Range
Return Set Point
Range
Finned Tube
Baseboard (default)
120-180°F
(48.5-82°C)
101-147°F
(38-63.5°C)
Fan Coil
140-180°F
(60-82°C)
116-147°F
(46.5-63.5°C)
Cast Iron Baseboard
100-170°F
(37.5-76.5°C)
86-139°F (30-59°C)
Low Mass Radiant
80-140°F
(26.5-60°C)
70-116°F
(21-46.5°C)
High Mass Radiant
80-120°F
(26.5-48.5°C)
70-101°F (21-38°C)
Radiators
120-170°F
(48.5-76.5°C)
101-139°F
(38-59°C)
Custom
104-180°F
(40-82°C)
86-149°F
(30-65°C)
Outdoor Temperature Range and Default Temperature Settings
Set Point Range Remarks
Outdoor Low
Temperature
-4°F (-20°C) to
Outdoor High
Temperature Set
Point - 9°F (5°C)
Default: 14°F
(-10°C)
Outdoor High
Temperature
Outdoor Low
Temperature Set
Point + 9°F (5°C) to
104°F (40°C)
Default: 70°F (21°C)

Navien NFB Series Specifications

General

Type	Condensing Boiler
Fuel Type	Natural Gas or Propane
Heat Exchanger	Stainless Steel
Vent Type	Direct Vent
Vent Diameter	2" or 3"