HYDRAULIC CONFIGURATION 4 (four) - SCHEME 2

SCHEME 2 – Thermal storage system (buffer) with double temperature sensor (S1 -S2)

Configuration description

The Scheme 2 of Hydraulic Configuration 4 provides for the use of a buffer equipped with:

• Upper sensor (S1) – controls the temperature of the upper part of the storage
• Lower sensor (S2) – controls the temperature of the lower part of the storage

Control unit parameters

Operational notes:
P26=4    Selects hydraulic configuration 4

P73=9   Enables the upper buffer temperature sensor S1 (input IN10)

P74=23  Enables the lower buffer temperature sensor S2 (input IN11)

Ih58= 2 °C  default  Buffer thermostat hysteresis (Value subtracted from the buffer setpoint to determine the generator reactivation threshold in standby condition)

Th85=60°C default  Lower buffer thermostat setpoint (S2)

D23=4°C  default  Additional delta to boiler setpoint for switching from modulation to standby at the end of time T43 (10 s default)

• Upper Buffer Sensor (S1)

Parameter P73 = 9 – Enables buffer sensor "S1"

This parameter enables buffer sensor S1, connected to input IN10.  (Sensor type: NTC-10K ; Moretti article code: MFSONDC)

UPPER BUFFER THERMOSTAT (S1) allows the stove/boiler to turn on or switch to stand-by mode (see important notes) based on the detected temperature.

Parameter Ih58 = 2 (default value)

Represents the hysteresis of the buffer thermostat (S1).

This value is subtracted from the set temperature point, defining the threshold for the automatic reactivation of the stove/boiler if it is in stand-by mode.

• Lower Buffer Sensor (S2)

Parameter P74 = 23 – Enables buffer sensor "S2"

This parameter enables buffer sensor S2, connected to input IN11. 

LOWER BUFFER THERMOSTAT (S2)

Parameter Th85 = 60°C (modifiable default value) Below this threshold, and considering the hysteresis value set with parameter Ih85, the stove/boiler activates the circulator P1 to ensure the recirculation of the heat transfer fluid. This guarantees forced circulation of the heat transfer fluid inside the system, avoiding thermal stagnation.

Important notes

To allow the stove/boiler to switch to stand-by mode, the temperature setpoints set for both buffer sensors (S1 and S2) must be reached simultaneously.

Connection of buffer temperature sensors (S1-S2)

Stoves with rear connectors:

• TECNIKA TURBO GLASS, TECNIKA FOR HOME, TURBO TOP, TURBO GLASS, PRESTIGE, EXCLUSIVE, TECNIKA EXCLUSIVE
• Sensor S1 is connected to control unit output IN10 (Sensor: NTC-10K; Moretti article: MFSONDC)
• Sensor S2 is connected to control unit output IN11 (Sensor: NTC-10K; Moretti article: MFSONDC)

Stoves without rear connectors:

• ALADINO, ELEGANCE, CLESSIDRA, ERGONOMIC, COMPACT, VISION, SLOT VISION, DOLBY
• Directly connect the cables of sensor S1 to the control unit PIN 52 – PIN 53 GND (output IN10) (Sensor: NTC-10K; Moretti article: MFSONDC)
• Directly connect the cables of sensor S2 to the control unit PIN 54 – PIN 55 GND (output IN11) (Sensor: NTC-10K; Moretti article: MFSONDC)

Verification of buffer temperature sensor connection

To verify the correct connection of the buffer temperature sensor, proceed as follows:

1. Access the remote control.
2. Enter the User Menu.
3. Select the “Information” item.

This screen displays the temperature detected by sensor S1 “T. Buffer” and the temperature detected by sensor S2 “Lower T. Buffer”

To modify the buffer temperature, proceed as follows:

1. Access the remote control.
2. Enter the User Menu.
3. Select the “Thermostats” item.
4. Select the “Buffer” item.

In this section, you can modify the buffer setpoint (S1).

Operating logics:

Upper Buffer Thermostat – S1

Sensor S1 manages:

• generator ignition;
• switch to stand-by mode.

 Parameter Ih58 = 2 °C (default) Represents the hysteresis of the upper buffer thermostat.

The reactivation threshold is determined as:

Buffer setpoint – Ih58

If the temperature drops below this value and the generator is in stand-by, it is automatically reactivated.

Lower Buffer Thermostat – S2

Parameter Th85 = 60 °C (default, modifiable)
Manages the protection of the lower part of the storage.

Considering the hysteresis (Ih85 = 2 °C default):

• If the temperature S2 falls below the intervention threshold,
• The control unit activates the circulator P1,

ensuring the circulation of the heat transfer fluid inside the buffer.

This logic prevents:

• excessive thermal stratification;
• prolonged presence of low-temperature heat transfer fluid in the lower part inside the buffer, avoiding thermal stagnation.

Condition for switching to Stand-by

For the stove/boiler to switch to stand-by mode, both conditions must be met simultaneously:

• reaching the setpoint set on sensor S1 (upper buffer);
• reaching the conditions set on sensor S2 (lower buffer).

The combined logic prevents premature generator shutdowns when the storage is not fully charged.