Navien NHB-055, Service Manual

Page: 51 / 147

NHB Service Manual 51 Version 1.0
Item Description Display
(C) Lowest Outdoor
Temperature
Setting
This mode is used to configure the heat load type to be used with the
Outdoor Reset Control mode
The boiler will operate at the high end of the supply or return set-point range
at this outdoor temperature.
Outdoor Low Temperature Setting Range
Setting range Default
-4°F(-20°C) ~ [Outdoor High Temperature
Set-point - 9°F(5°C)]
14°F(-10°C)
For Celsius (°C) mode;
ex) at - 10°C
For Fahrenheit (°F) mode;
ex) at 14°F
Lowest Outdoor Reset is not used
(D) Highest Outdoor
Temperature
Setting
This mode is used to configure the heat load type to be used with the
Outdoor Reset Control mode
The boiler will operate at the high end of the supply or return set-point range
at this outdoor temperature
Outdoor Low Temperature Setting Range
Setting range Default
[Outdoor Low Temperature Set-point +
9°F(5°C)] ~ 104°F(40°C)
70°F(21°C)
For Celsius (°C) mode;
ex)at 21°C
For Fahrenheit (°F) mode;
ex) at 70°F
Highest Outdoor Reset is not used
(E) Boost Interval
Time Setting
The boost interval time may be set to prevent interruption in space heating
while using the Outdoor Reset Control mode, due to changes in heat load
conditions. With the boost interval time enabled, the boiler increases the
space heating supply temperature by 9°F(5°C) and the return temperature by
5°F(3°C) after a set time elapses.
Setting Range Remarks
Boost Interval Time 0-120 min (0 : OFF) Default : OFF (0)
Boost Temperature
Space Heating Supply
(Fixed Value): 9°F(5°C)
Space Heating Return
(Fixed Value): 5°F(3°C)
If Boost Interval Time set is
30 minutes