LAARS NeoTherm LC NTV1700 - Install and Operating Manual - Manual (Page 71)

NeoTherm LC Boilers and Water Heaters Page 67
Low water temp. -
If the outdoor temperature reaches the Max.
Outdoor Temp. or higher, the system will
use the Low Water Temp value as the new
setpoint. In the example shown in Fig. 86,
the Max. Outdoor Temp. is set to 70°F. If
the outdoor temperature reaches 70°F or
above, the system will use the Low Water
Temp. value (100°F) as the setpoint.
Min. boiler water temperature -
If a value is entered here, the temperature
in the boiler will never be allowed to drop
below this temperature. This will protect
the boiler against possible damage due to
expansion of ice inside the unit.
9. The Show Line button at the bottom of the
screen displays a curve which shows how
the system will behave at different outdoor
temperatures. See Fig. 87. (This screen
is also explained in the section on “About
Outdoor Reset.”)
Fig. 87 – Outdoor Reset Display
10. From the Outdoor Reset screen, press the left-
arrow or right-arrow until you see the Warm
Weather Shutdown screen (Fig. 88).
Fig. 88 – Warm Weather Shutdown
When enabled, the Warm Weather Shutdown
feature will turn off the Central Heating
functions when the outdoor temperature
exceeds the setpoint. This prevents the system
from running when there is no need for heat.
Enable -
These options determine how quickly
the system shuts down after the outdoor
temperature rises above the setpoint. The
options are Shutdown immediately/ After
demand ends/ Disabled.
Setpoint -
If the outdoor temperature is higher than
this, the system will shut off the Lead/Lag
Central Heating functions.
11. Press the left-arrow or right-arrow until you
see the Rate Allocation screen (Fig. 89).
Fig. 89 – Rate Allocation
As the load on the system increases, the first
boiler in the Lead/Lag chain will increase the
fan speed until it reaches a certain percentage
of the total output (the “base load”). At that
point, the controller will start the second boiler
in the lead/lag chain. See the explanation at
the beginning of this section and Fig. 50.
Base Load Common -
As the demand increases, this sets the point
at which the controller starts another burner
in the Lead/Lag chain.
To prevent short-cycling, the base load setting
should be set at the values shown in Table 16,
or set to higher values.