NTI FTVN - Type of Temperature Control; Slope of Outdoor Reset Curve

62
AUTO
1
The Parallel Shift can be adjusted from the home screen using the CH + and - buttons (Figure
57, Item 8).
With the rst press of the CH + or - button, the display shows the current CH target temperature
(e.g., 130
o
F).
After a 3-5 second delay, the display begins ashing the current oset (Parallel Shift) setting.
Subsequent CH + or - button presses adjusts the oset up or down.
After a few seconds the display shows the new CH target temperature (e.g., 138
o
F), then returns
to the home screen.
Figure 66 - Automatic Boost
10 min 10 min 10 min
+ 10%
+ 10%
Each line represents a
1% decrease in setpoint
per minute
after the call has been met
Slope of Outdoor Reset Curve
Thermostat
O
Thermostat
O
Thermostat
On
L. Auto Boost
(e.g. Parameter 4.7.5 for Zone 1)
When enabled (4.7.5 = 1), Auto Boost acts to automatically
adjust the Slope of the Outdoor Reset Curve to better
match the needs of the heating system. The function boosts
the boiler target temperature by increasing the Slope 10%
every 10 minutes a call for heat is continuously active, to
a maximum of 2X the nominal Slope setting (4.2.2). While
the heat call is satised, the Slope decreases by 1% every
minute to a minimum of the nominal Slope setting (4.2.2).
Auto Boost is only applicable when 4.2.1 = 3 or 4.
NOTE: The boiler supply temperature is limited upwards by
the xed maximum temperature (4.2.5) and downwards by
the xed minimum temperature (4.2.6).
K. Parallel Shift of Reset Curve
(e.g. Parameter 4.2.3 for Zone 1)
When the Reset Curve results in a boiler target temperature
that is too high or too low (i.e., heats the building too quickly
or slowly), Parallel Shift can be used to oset the curve up or
down to increase or decrease the boiler target temperature.
NOTE: Adjusting Parallel Shift is only possible when Auto
Boost is OFF (4.7.5 = 0).
Figure 67 - Parallel Shift of Reset Curve
179 °F
120 °F
20 °F
0,4 3,51,3
Default
65 °F 80 °F
Target CH supply temperatureTarget CH supply temperature
Target CH supply temperature
Outdoor temperature
179 °F
120 °F
Outdoor temperature
Decrease parallel shift
Increase parallel shift
+25°F
0 °F
-25°F
Default
179 °F
120 °F
Outdoor temperature
Part 9 - Controls