NTI Matrix Installation And Operation Instructions Manual page 47

Matrix
Outdoor Sensor (10K)
To fully take advantage of the energy saving features of the Matrix, it is necessary to install the outdoor sensor
provided. Install the sensor preferably on the north, or coldest side of the building, not within 10 feet of the
discharge of the gas vent outlet, or other sources of heat. The outdoor sensor connects to the low voltage
terminal strip, on the left-hand side of the boiler, to the terminals labeled "Outdoor Sensor"; see Figure 12-2.
Calculating Outdoor Reset Curve (RES)
Formula:
Operating Temperature = {(RES – Outdoor Temp) x (HYD – RES) / RES} + RES
Note: Substitute HYD for HI during a call for Emergency Heat.
Example:

There is a call for Hydronic heat; therefore the control uses the HYD programmed
setting.

The HYD is programmed to be 160°F.

The RES is programmed to be 85°F.

The outdoor temperature is 40°F.
Operating Temperature = {(85 – 40) x (160 – 85) / 85} + 85 = 125°F
The following chart illustrates the effect of changing outdoor temperature on the boiler operating
temperature for the above example.
Reset Curve for Res=85 & Setpoint=160
170
150
130
110
90
70
-10 0 10
Table 13-6 Outdoor Reset RES Setting Recommendations
Boiler Set Point – HYD
80 – 110
110 – 140
140 – 170
170 – 200
20 30 40 50
Outdoor Temperature (deg.F)
Outdoor Reset – RES
70 – 80
80 – 90
90 – 100
100 – 110
Installation and Operation Instructions
60 70 80 90 100
47