NTI INSTALLATION MANUALS

Part 9 - Controls

K. Parallel Shift of Reset Curve (e.g. Parameter 4.2.3 for Zone 1)

179 °F

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.

+25°F

Increase parallel shift

0 °F

Default

Decrease parallel shift

-25°F

120 °F

NOTE: Adjusting Parallel Shift is only possible when Auto Boost is OFF (4.7.5 = 0).

Target CH supply temperature

Outdoor temperature

Figure 69 - Parallel Shift of Reset Curve

The Parallel Shift can be adjusted from the home screen using the CH + and - buttons (Figure 59, 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.

1

AUTO

After a few seconds the display shows the new CH target temperature (e.g., 138 o F), then returns to the home screen.

L. Auto Boost (e.g. Parameter 4.7.5 for Zone 1)

Thermostat On

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).

Thermostat Off

Thermostat Off

+ 10%

+ 10%

Each line represents a 1% decrease in setpoint per minute after the call has been met

Slope of Outdoor Reset Curve

10 min 10 min 10 min

Figure 68 - Automatic Boost

63