HDG F20, Руководство по эксплуатации

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4 Planning and installation – Hydraulic connection
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around the water-cooled heat-exchanger surfaces. This
condensation, in combination with combustion residue, can lead to
corrosion.
For these reasons, a return temperature control must be installed for
the HDG F20-50 heating system. The return temperature control
causes the water from the boiler return flow to be mixed with the
water from the boiler supply flow until the minimum return
temperature has been reached.
✎
The minimum return temperature is listed in chapter “3 Mode of
operation”, section “3.3 Technical data”.
The control of the return temperature is handled by the HDG controls
control unit.
The return temperature control consists of a 3-way mixing valve with
a 230 V servo drive (running time 120-240 s) and a circulation pump
from energy efficiency class A. For the HDG F20-50, we recommend
• Wilo 30/1-7.5, 3-way mixing valve DN 32 (or equivalent).
The return temperature control may not be further than 5 metres
from the boiler.
The hydraulic system must be installed in accordance with specific
technical principles of heating engineering. Take into account the
stop cocks required for maintenance work and repairs.
The return temperature control must be installed according to the
specifications of HDG Bavaria.
4.4 Hydraulic connection
✎
See the supplied schematic diagram and electrical circuit
diagram.
The pipe dimensions must be adapted to meet the requirements at
the site. Take the water-side connections of the boiler for the supply
and return into account.
✎
See chapter “3 Mode of operation”, section “3.3 Technical data”.
The return temperature control is not designed for the use of a
gravity brake and this should therefore not be installed.
The hydraulic connection depends on the schematic diagram
selected in the respective HDG controls system.