Laars NTV1000, Installation And Operation Instructions Manual

Page: 77 / 138

NeoTherm Boilers and Water Heaters
Page 73
Fig. 96 – 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 compensate
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. 97.
Fig. 97 – Show Line Screen
In the display shown above, 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.
When Outdoor Reset is enabled, and the outdoor
temperature falls between the maximum and
minimum outdoor temperatures (70° and 32° in the
example above), the setpoint will be adjusted down
by about 1° for every 2° increase in the outdoor
temperature. For example, if the outdoor temperature
rises by 10°, the Outdoor Reset function will adjust
the setpoint down by about 5°.