Type Of Temperature Control; Slope Of Outdoor Reset Curve - NTI FTVN085 Installation Start-Up Maintenance

Residential condensing gas boiler

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Instructions manual (12 pages)

Table Of Contents

100

Table of Contents

Part 9 - Controls

Part 1 - General Safety Information

I. Type of Temperature Control

(e.g. Parameter 4.2.1 for Zone 1)

0 = Fixed Outlet Temperature - When operating for central heating, the boiler operates at a fixed supply temperature equal to the setting of pa-

rameter 4.0.2, which is adjustable via the CH + and - buttons on the home screen, with a range defined by parameters 4.2.5 and 4.2.6. The supply

temperature is fixed and does not change due to indoor or outdoor temperature conditions.

1 = Basic Temp. Control - The boiler uses the ON/OFF condition of the room

thermostat to boost/reduce the boiler target temperature. With a starting*

(first time) boiler target temperature of 136

function boosts the target temperature by 7

heat is continuously active. Similarly, the target temperature is reduced 7

every 16 minutes** that the heat call is continuously inactive. The temperature

will boost/reduce a maximum of 3 times (21

OFF cycle.

*NOTE: The boiler starting target temperature can be manually offset up or

down via the Parallel Shift setting (4.2.3), which is adjustable from the home

screen via the CH + and - buttons.

**NOTE: The default boost interval of 16 minutes can be adjusted via parame-

ter 2.4.4.

***NOTE: The boiler supply temperature is limited upwards by the fixed maximum temperature (4.2.5) and downwards by the fixed minimum

temperature (4.2.6).

2 = Indoor Temp. Reset - The boiler target temperature automatically adjusts between the Min and Max Temperature Settings (4.2.6 and 4.2.5),

based on the input temperature provided by an optional NTI Room Sensor, in accordance with the following formula:

Boiler Target Temp = Min Temp (4.2.6) + Room Sensor Influence (4.2.4) X [Room Setpoint - Room Temp] + Parallel Shift of Reset Curve (4.2.3)

3 = Outdoor Temp. Reset - The boiler target temperature automatically adjusts between the Min and Max Temperature Settings (4.2.6 and

4.2.5), based on the input temperature provided by the included Outdoor Sensor (or Internet Weather via WiFi connection), in accordance with

the following formula:

Boiler Target Temp = Min Temp (4.2.6) + Slope of Outdoor Reset Curve (4.2.2) X [Room Setpoint (4.0.0) - Outdoor Temp] + Parallel Shift of Reset Curve (4.2.3)

Where: Room Setpoint, in the absence of an NTI Room Sensor, defaults to 66

4 = Indoor and Outdoor Temp. Reset - The boiler target temperature automatically adjusts between the Min and Max Temperature Settings

(4.2.6 and 4.2.5), based upon the input temperatures provided by an optional NTI Room Sensor AND the included Outdoor Sensor (or Internet

Weather via WiFi connection), in accordance with the following formula:

Boiler Target Temp = Min Temp (4.2.6) + Slope of Outdoor Reset Curve (4.2.2) X {Room Sensor Influence (4.2.4) X [Room Setpoint - Room Temp] + [Room Setpoint -

J. Slope of Outdoor Reset Curve

(e.g. Parameter 4.2.2 for Zone 1)

The boiler control adjusts the supply temperature according

to the outdoor temperature. The lower the outdoor

temperature, the higher the boiler supply temperature, and

vice versa.

The supply temperature needed to efficiently satisfy a call for

heat from a thermostat depends on the heating system and

building conditions (building materials, insulation, etc.)

The Slope of the Outdoor Reset Curve may be adjusted

to adapt the boiler supply temperature to installation

conditions.