Function Description/System Design - Wolf CGB-75 Installation And Technical Manual

Hydraulic
Design information
30 62 555_0709
Function description /
system design
A dirt filter should be installed in the boiler return.
The use of a low loss header is recommended.
Using the pump assembly with a modulating pump from the Wolf accessories range
avoids raising the return temperature, as the pump output is controlled in the same
way as the boiler output.
Injection control is only advisable in conjunction with heating circuit pumps. We
recommend using mixer circuits, as consumer circuits have low system temperatures
in the spring and autumn. The return line to the appliance should have a dirt trap.
Deposits in the heat exchanger may lead to boiling noise, a drop in performance or
the destruction of the appliance.
A heat exchanger protection function is integrated into the CGB-75/100. This
prevents stresses in the material by limiting the maximum temperature differential
between the flow and return. As of 28 K, the output is reduced. If 38 K is nevertheless
reached, the burner shuts down briefly without a fault message. This characteristic
must be taken into account when selecting the components (e.g. pumps, heat
exchangers and cylinders).
With regard to fill and top-up water, refer to the VDI guideline 2035 and/or the installation
instructions to avoid limescale deposits and corrosion in the heat exchanger.
In larger systems, the circulation pumps should be sized individually to the circuits, and
the pump assemblies should therefore be selected in line with demand.
Information on expansion vessel sizing can be found in the pricelist.
A minimum pressure limiter (0.8 bar) is integrated into the CGB-75/100. If the majority
of radiators are located below the appliance (e.g. in the case of attic installations), a
low water indicator should also be used.
The thermostatic DHW mixing valve on the solar cylinder enables the draw-off
temperature to be reduced (anti-scalding protection). Where DHW demand is high, we
recommend connecting several cylinders in series.
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