LAARS NeoTherm LC NTV1700 - Install and Operating Manual - Manual (Page 73)

NeoTherm LC Boilers and Water Heaters Page 69
2. Set the outdoor reset and warm weather
shutdown parameters as desired.
How to get there – Outdoor Reset Screen and Warm
Weather Shutdown Screen
Home Page <Press View Lead/ Lag button> Lead/ Lag
Screen <Press Lead/ Lag Master button> Lead/ Lag
Screen <Press Configure button> Lead/ Lag Master
Configuration Screen <Press Advanced Settings button>
Select the Outdoor Reset Screen or the Warm Weather
Shutdown Screen
Fig. 92 – Outdoor Reset
For a detailed explanation of the Outdoor
Reset function, see the section titled “About
Outdoor Reset” which follows.
Fig. 93 – 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.
About Outdoor Reset
The Outdoor Reset feature calculates a correction
for the Lead/Lag setpoint depending on the outdoor
temperature. This allows the system to adjust for
changes in the outdoor temperature and run more
efficiently.
The Show Line button at the bottom of the Outdoor
Reset screen displays a curve which shows
how the system will behave at different outdoor
temperatures. See Fig. 94.
Fig. 94 – Show Line Screen
The display shown above show the action of the
system with one possible group of settings. The
green line shows the setpoint used by the system.
• Without Outdoor Reset, this would be a
constant 120°F (or whatever value you chose),
regardless of the outdoor temperature. The
green line in the graph would run straight
across the display.
• However, with the Outdoor Reset feature
turned on, the system will adjust for changes
in the outdoor temperature. Let’s take a
detailed look at behavior of the setpoint,
shown by the green line in the display. For
cold outdoor temperatures (below 32°F), the
setpoint remains unchanged (120°F). As the
temperature begins to rise above 32°F, the
Outdoor Reset function causes the setpoint to
be lowered. At these warmer temperatures,
the heating load on the system is not as great,
so the system does not have to reach as high
a temperature to handle the load. As you can
see from the display, at an outdoor temperature
of about 70°F, the system stops adjusting the
setpoint. Above 70°F, the setpoint is constant
at 100°F.