HYDRAULIC CONFIGURATION 4 (four) - SCHEME 2

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

Configuration description

Scheme 2 of Hydraulic Configuration 4 involves the use of a buffer equipped with:

• Upper probe (S1) – controls temperature of the upper part of the storage
• Lower probe (S2) – controls 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 probe S1 (input IN10)

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

Ih58= 2 °C  default  Buffer thermostat hysteresis (Value subtracted from 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 Probe (S1)

Parameter P73 = 9 – Enables buffer probe "S1"

This parameter enables the buffer probe S1, connected to input IN10.  (Probe type: NTC-10K ; Moretti part number: MFSONDC)

UPPER BUFFER THERMOSTAT (S1) allows the stove/boiler to turn on or switch to standby 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, defining the threshold for automatic reactivation of the stove/boiler if it is in standby mode.

• Lower Buffer Probe (S2)

Parameter P74 = 23 – Enables buffer probe "S2"

This parameter enables the buffer probe S2, connected to input IN11. 

LOWER BUFFER THERMOSTAT (S2)

Parameter Th85 = 60°C (default modifiable 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, preventing thermal stagnation.

Important notes

To allow the stove/boiler to switch to standby mode, both temperature setpoints for the buffer probes (S1 and S2) must be reached simultaneously.

Verification of Buffer Probe Configuration

Access the menu Information → T. Buffer and check the displayed value.

• T. Buffer = 0 °C: the Buffer probe input is not enabled. Verify that the hydraulic configuration is set to P26 = 4 (configuration with buffer).
• T. Buffer = - 10 °C: the Buffer probe input is enabled (P73 = 9), but no probe is detected. Verify that an NTC 10k probe is installed, correctly connected to input S1, and that the hydraulic configuration is set to P26 = 4.

Connection of buffer temperature probes (S1-S2)

Stoves with rear connectors:

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

Stoves without rear connectors:

• ALADINO, ELEGANCE, CLESSIDRA, ERGONOMIC, COMPACT, VISION, SLOT VISION, DOLBY
• Connect the cables of probe S1 directly to the control unit at PIN 52 – PIN 53 GND (output IN10) (Probe: NTC-10K; Moretti part number: MFSONDC)
• Connect the cables of probe S2 directly to the control unit at PIN 54 – PIN 55 GND (output IN11) (Probe: NTC-10K; Moretti part number: MFSONDC)

Verification of buffer temperature probe connection

To verify the correct connection of the buffer temperature probe, 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 probe S1 “T. Buffer” and the temperature detected by probe 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, it is possible to modify the buffer setpoint (S1).

Operating logics:

Upper Buffer Thermostat – S1

The probe S1 manages:

• generator ignition;
• switching to standby 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 falls below this value and the generator is in standby, it is automatically reactivated.

Lower Buffer Thermostat – S2

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

Considering hysteresis (Ih85 = 2 °C default):

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

ensuring 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 Standby

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

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

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