Heat production

S1256 is supplied with a heating control system, which means that the heating supply to the house takes place according to selected settings. When connecting to a system with thermostats on all radiators (or underfloor heating coils), either a bypass valve must be fitted or some of the thermostats must be removed to ensure there is sufficient flow. For more information about heat production, see the Installer Manual.

Heating and cooling production

S1256 is supplied with a heating and cooling control system, which means that the heating and cooling supply to the house takes place according to selected settings. When connecting to a system with thermostats, either a bypass valve must be fitted or some of the thermostats must be removed to ensure there is sufficient flow. For more information about heating and cooling production, see the Installer Manual.

Hot water production

When there is demand for hot water, S1256 prioritises this and switches to hot water mode. There is no heat production in this mode.

If the hot water temperature exceeds 60 °C, the installation must be supplemented with a mixing valve.

For more information about hot water production, see the manual for S1256.

Cooling production

Passive cooling, cooling function without the compressor running, is achieved by connecting a cooling system to the heat pump’s brine circuit. The collector’s low temperature can be utilised for comfort cooling.

When cooling is required (activated from the outdoor temperature sensor and any room sensor) the circulation pump is activated and the shunt valve provides the correct supply temperature.

External heating medium pump

An external heating medium pump can be connected via an AUX output in S1256. If the AUX output is being used for any other function, the heating medium pump can instead be connected via the AXC module. The heating medium pump can be connected via the following functions:

• additional heat (accessory AXC 40)

• shunt-controlled additional heat (accessory AXC 40)

• pool (accessory POOL 40)

Heating system 2

This function requires the ECS 40/ECS 41 accessory. Shunt valve, supply and return line sensors, as well as circulation pump, are connected to other heating circuits with a lower temperature demand (e.g. underfloor heating system). The temperature in the extra heating system follows the selected curve slope and offset setting. Up to 8 extra heating systems can be connected to the installation.

For further information, see the Installer Manual for the accessory.

See the valve’s manual for a port description.

Climate system 2

This function requires the ECS 40/ECS 41 accessory. Shunt valve, supply and return line sensors as well as circulation pump are connected to the extra climate system with a lower temperature demand. The temperature in the extra climate system is in accordance with the selected curve slope and offset setting.

Up to 8 extra climate systems can be connected to the installation.

For further information, see the Installer Manual for the accessory.

See the valve’s manual for a port description.

Extra hot water heaters

The system should be supplemented with an extra water heater, if a large bath tub or other significant consumer of hot water is installed.

External brine pump

An external brine pump can be connected via an AUX output in S1256. If the AUX output is being used for any other function, the brine pump can instead be connected via the AXC module. The brine pump can be connected via the following functions:

• ground water pump (accessory AXC 40)

HRV unit

This function requires the accessory ERS, which is controlled by S1256. ERS recovers the energy from the ventilation air and supplies it to the property.

For further information, see the Installer Manual for the accessory.

Exhaust air recovery

This function requires the accessory FLM S45. FLM S45 is an exhaust air module that is controlled by S1256. FLM S45 recovers energy from the exhaust air and supplies it to the brine.

For further information, see the Installer Manual for the accessory.

Ventilation

‘Ventilation only’ means that the heat pump recovers the heat from the ventilation without using boreholes or ground collectors, and supplies it to the heating system.

For more information, see the manual for the ventilation.

Ground water system

This connection enables the use of ground water as heat source. The ground water is pumped up to an intermediate heat exchanger. An intermediate heat exchanger is used to protect the heat pump's exchanger from dirt and freezing. The water is released into a buried filtration unit or a drilled well.

The ground water pump runs at the same time as the brine pump.

Active cooling (cooling in 4-pipe system)

With the accessory ACS 45, a separate cooling system can be connected via a reversing valve. ACS 45 allows both heat and cooling production independently of each other.

Passive cooling occurs without the compressor running, active cooling occurs when the compressor is running. The cooling system is connected to the heat pump’s brine circuit.

When cooling is required (activated from the outdoor temperature sensor (EB100-BT1) and room sensor (EB100-BT50), where applicable), the shunt valve (EQ1-QN18) and the circulation pump (EQ1-GP10) are activated.

See the valve’s manual for a port description.

Heat dump

If there is excess heat, this is dumped to a coolant radiator or to the collector.

Separate systems for heating and cooling (in 2-pipe system)

In installations where some climate systems are not insulated against condensation, the flow to these climate systems can be shut off by a shut-off valve during cooling operation.

Passive cooling (cooling in 2-pipe system)

This function requires the PCM S40/PCM S42 accessory. The cooling system is connected to the heat pump’s brine circuit, whereby cooling is supplied from the collector via circulation pump, shunt valve and reversing valve.

When cooling is required (activated from the outdoor temperature sensor (EB100-BT1) and room sensor (EB100-BT50), where applicable), the reversing valve, the shunt valve and the circulation pump are activated.

The shunt valve regulates so that the sensor reaches the current set point value corresponding to the outdoor temperature and the set min. value for the cooling temperature.

When there is a risk of condensation, components and climate systems must be insulated against condensation in accordance with current standards and provisions, or the min. supply temperature must be limited.

Passive cooling (cooling in 4-pipe system)

This function requires the PCS 44 accessory. The cooling system is connected to the heat pump brine circuit, through which cooling is supplied from the collector via the circulation pump and the shunt valve.

When cooling is required (activated from the outdoor temperature sensor (EB100-BT1) and room sensor (EB100-BT50), where applicable), the cooling shunt (EP44-QN18) and the circulation pump (EP44-GP10) are activated.

The shunt valve regulates so that the cooling sensor reaches the current set point value corresponding to the outdoor temperature and the set min. value for the cooling temperature (to prevent condensation).

If the FLM S45 accessory is installed with PCS 44, the cooling output will be reduced.

See the valve’s manual for a port description.

Pool

With the POOL 40 accessory, the heat pump can be used to heat a pool.

For further information, see the Installer Manual for the accessory.

Filling kit

In order to fill the system easily with brine, the accessories KB 25/KB 32 are available. These consist of a filterball, reversing valve and shut-off/filling valves, and are available in two sizes.

KB 25 for heat pump sizes up to 13 kW and KB 32 for heat pump sizes up to 30 kW.

Solar panels

This function requires the NIBE PV accessory. NIBE PV is a complete modular system with solar panels in several basic outputs. NIBE PV is connected to S1256, which adjusts to the generated solar electricity produced.

For further information, see the Installer Manual for the accessory.

Addition

Additional heat that requires the AXC 40 accessory. AXC 40, via a control signal, can control step-controlled additional heat.

The additional heat is used for heat production.

For further information, see the Installer Manual for the accessory.

Shunt controlled additional heat

Additional heat that requires the AXC 40 accessory. AXC 40, via a control signal, can control additional heat, which can also be prioritised.

The additional heat is used for heat production.

For further information, see the Installer Manual for the accessory.

Room control

S1256 is supplied with a room sensor enclosed (BT50). The room sensor has a number of functions:

1. Shows current room temperature in the display on S1256.

2. Option of changing the room temperature in °C.

3. Provides the option of fine-tuning the room temperature.

For more information about the room sensor, see the Installer Manual for S1256.

Buffer vessel (UKV)

A 3-pipe-connected buffer vessel is used when the system volume in the climate system is below the minimum recommended volume for the heat pump and/or the flow in the heating system is restricted without control.

For further information, see the Installer Manual for the accessory.

Hot water circulation

A circulation pump can be controlled by S1256 to circulate the hot water. The circulating water must have a temperature that prevents bacterial growth and scalding, and national standards must be satisfied. See the appropriate Installer Manual for more information.

The hot water circulation pump can be connected via an AUX output in S1256. If the AUX output is being used for any other function, the hot water circulation pump can instead be connected via the accessory AXC 40. The hot water circulation pump can be connected via the following functions:

• hot water comfort (accessory AXC 40)