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2.
For the Installer
2.2 System
2.2.1 Area of use
For heating buildings acc. to EN 12831.
The boilers are designed and approved as heat generators for hot water heating systems with a permissible flow
temperatures of up to 90°C. They may be installed only in sealed systems. The maximum flow temperature is
factory-set at 75°C. In the service level, the max. boiler temperature can be increased to 85 °C. To do this, an ac-
cumulator tank has to be installed, which is loaded by the BioWIN.
2.2.2 Standards
The following European standard should be followed: EN 12828, this specifies that the following should be fitted:
a) A closed expansion tank.
b) A reliably functioning safety valve installed at the highest point of the boiler or at a non-closable line.
c) A thermometer, a pressure gauge.
d) A low-water cut-off: A low-water cut-off is not required for systems providing up to 300 kW nominal thermal
output, if it can be assured that excess heating will not result from a lack of water in the system.
If the boiler is above the radiators, then a low-water cut-off must be installed.
2.2.3 Heating circuits
A motorised mixing valve is always required for the BioWIN 2 in order to protect the boiler
and one must be fitted
in each heating circuit
. A feed contact thermostat (FK-001) must be installed for underfloor circuits.
2.2.4 Circulation pump
Since 2013, in Europe new circulation pumps are required to fulfil minimum energy efficiency requirements. Ple-
ase refer to the Energy Efficiency Index (EEI).
2.2.5 Return temperature
The return flow temperature increase installed as standard means that BioWIN 2 can be operated with a return
temperature down to min. 20 °C. No external return flow temperature increase is required.
Exception: Systems with a buffer in which the buffer is loaded directly from BioWIN 2 with a return hold-up group.
2.2.6 Accumulator tank
In principle a pellet boiler system does not need an accumulator tank. A guaranteed minimum heat consumption
is required, e.g. fit a consumer circuit that cannot be blocked off or do not fit thermostat valves on all radiators.
The BioWIN 2 needs a buffer if:
– the total heating requirements of the building according to the ÖNORM M 7500 or EN 12831 calculation are less
than 50 % of the boiler‘s nominal output.
– a flow temperature of 75-85 °C is required.
Information!
If using a buffer, the BioWIN 2 return flow temperature must be increased – see hydraulic diagram
in the planning documents.
