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Installation to be provided by the customer
The boiler is suitable and permissible as a heat generating device for hot-water
heating systems with a fl ow temperature of up to 95° C and a maximum allo-
wable working pressure of 3 bar.
The appliance must be installed following the instructions of this operating ma-
nual and in conformance with the applicable national and European standards
as well as the regional regulations.
Further points to be observed:
• Heating room guidelines
• State building regulations
• Local building regulations
• Industrial regulations and local fi re protection laws
• Environmental laws
• Regulations of the local power supply company.
Upon completion of the connection work a test run must be carried out du-
ring which all control and safety devices are adjusted and checked for correct
functioning.
Heat output to water
The heat requirement during operation must exceed 1.6 kW. If the demand or
heat supplied is lower, the built-in safety devices would be activated and/or the
appliance would be shut down.
Return fl ow temperature boost
Operating temperatures that are too low (fl ow and return fl ow temperatures
that are too low) will reduce the service life of the boiler signifi cantly.
When the temperature is below the water dew point, water containing chemical
substances with various types of activity condenses on the boiler surface and
can accelerate corrosion. Temperatures below the dew point primarily occur
in low-temperature heating installations (return temperatures down to below
25°C), in installations without a mixer, in the case of extreme light-load opera-
tion during changes in season and in constant light-load operation caused by
a boiler that is dimensioned too large.
Therefore the return fl ow temperature must be at least 55°C at the return fl ow
connecting piece of the appliance. The ideal return fl ow temperature at the
boiler inlet is around 60°C. The return fl ow temperature boost (the pump for
the return fl ow temperature boost must be installed in the return fl ow) should
be mounted as near as possible to the boiler so that the mixing temperature
at the mixing valve corresponds to the return fl ow temperature at the boiler.
Temperature safety relief valve
The heat exchanger serves to protect the boiler from overheating when the
pump is stationary and must not be used to provide domestic hot water. The
safety mechanisms must still be accessible after the installation. The drain must
be visible for checking the temperature safety relief valve for proper functio-
ning, therefore use the drain funnel (Figure 19).
At least once a year the temperature safety relief valve must be checked for
correct operation. To do this, press the red cap against the valve and water
must fl ow into the drain funnel. Should the safety valve drip, the seal and valve
seat must be cleaned. The calcifi cation state of the safety devices must also be
checked at least once a year.
Expansion tank
If the boiler hot-water circuit is not directly connected to a heating circuit with
integrated expansion tank, or if it can be disconnected from this circuit, a
separate expansion tank (type-approved) is required. The installation and the
calculation of the dimensions of the expansion tank must comply with DIN
EN12828 and DIN EN13831. The expansion tank must be installed in rooms that
are protected from frost. For further details (e.g. maximum operating tempera-
ture, etc.) refer to the information given by the manufacturer.
Figure 18
Figure 19
Sensor for temperature safety
relief valve
Temperature safety relief valve
(Watts STS20)
Discharge
Supply
Drain funnel
Cleaning-T
Safety valve
Check valve
Pressure reduction
valve with gauge
Cold water pipe
DETAIL A
MAßSTAB 2 : 5
Automatic air bleed device
Circulating pump
Return fl ow temperature boost
Caution: Direction of fl ow
Temperature safety
relief valve