Navien NCB-20LHWE, Installation & Operation Manual

Page: 49 / 80

Setting the Lowest Outdoor Temperature
Display Description
Lowest outdoor temperature
(°C)
Lowest outdoor temperature
not in use
This mode is used to configure the lowest outdoor temperature.
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
Range Remarks
-20°C – [Outdoor Max
Temperature set point - 5°C]
Default: - 10°C
Setting the Highest Outdoor Temperature
Display Description
Highest outdoor temperature
(°C)
Highest outdoor temperature
not in use
This mode is used to configure the highest outdoor
temperature. The boiler will operate at the low end of the supply
or return set-point range at this outdoor temperature.
Outdoor High Temperature Setting Range
Range Remarks
[Outdoor Min Temperature set
point + 5°C] – 40°C
Default: 21°C
Setting the Heat Load for the Outdoor Reset Control Mode
Display Description
Outdoor Reset heat load types
1: Finned tube baseboard
2: FAN coil
3: Cast iron baseboard
4: Low mass radiant
5: High mass radiant
6: Radiator
7: Custom
Outdoor Reset heat load not
selected
This mode is used to configure the heat load type to be used
with the Outdoor Reset Control mode.
A preset or user-defined temperature range is selected
automatically based on the heat load type selected.
Types of Heat Load
Heat Load
Supply Set-
point Range
Return Set-
point Range
Remarks
1. Finned
Tube
Baseboard
48.5–82°C 38–63.5°C Default
2. Fan Coil 60–82°C 46.5–63.5°C
3. Cast Iron
Baseboard
37.5–76.5°C 30–59°C
4. Low Mass
Radiant
26.5–60°C 21–46.5°C
5. High Mass
Radiant
26.5–48.5°C 21–38°C
6. Radiators 48.5–76.5°C 38–59°C
7. Custom
Supply Control:
Absolute MIN/
MAX set point
Return Control:
Absolute MIN/
MAX set point
User-
defined
Heat loads 1-6 show the preset temperature ranges based on
the load type selected, while heat load 7 provides a custom
temperature range. When the custom temperature range is in
use, the boiler operates based on the user–defined “Absolute
Min” and “Absolute Max” temperature settings.
49 Operating the Boiler