eta PelletsCompact33-50 kW, Operation

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ETAtouch controller [Solar] function block
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5.7.2 Solar heating system with 2 tanks
Switching between several tanks
If the solar heating system charges several tanks (for
example, buffer and hot water tanks) it will switch
between tanks on the basis of the currently set
priorities. The tank with the highest priority is charged
first.
Fig. 5-57: Solar heating system for the buffer and hot water
tank
If the solar power is not sufficient for charging the tank
with the highest priority (collector is only warmer by the
difference [Switch-off diff.] than the tank that currently
requires charging), the tank with the next highest
priority is charged after the minimum time has elapsed
(factory setting 20 minutes).
If the solar power increases once more, after the
minimum time has elapsed solar charging switches
back to the tank with the higher priority. This ensures
that the tank with the highest priority is always charged
first.
Uniform charging of tanks without consideration
of individual priorities is also possible. The
[Service] permission is required for this. Then you can
use the [Changeover if diff. >] parameter in the solar
heating system text menu to configure the temperature
difference between the tanks.
5.7.3 Solar heating system for buffer with
2 internal coils
Switching between two internal coils
When switching between two internal coils, charging is
defined in two different areas of the buffer. The
purpose is to produce a sufficiently high temperature in
the top part of the buffer, so that the boiler does not
have to start for hot water charging.
Fig. 5-58: Solar heating system with switching between two
coils at the buffer
The solar pump starts as soon as the panel is warmer
than the current temperature in the upper buffer area
[Buffer top Solar].
An internal target temperature [Buffer target solar] is
provided to control switching. The target temperature
is determined by referencing current requirements or
minimum temperatures and can be viewed in the
buffer's text menu under:
The conditions for solar charging into the upper buffer
coil are:
• The buffer is not currently charged from the boiler.
• The outside temperature is above the set minimum
temperature of 10 °C ([Min. out. temp. Solar prio.],
see chapter
5.3.4.7 "Min. out. temp. Solar prio." )
• The temperature in the upper buffer area [Buffer
top Solar] is lower than the target temperature
[Buffer target solar]
If all conditions are met and the collector is sufficiently
warm, the upper buffer area will be charged until the
target temperature [Buffer target solar] is exceeded.
Subsequently, solar charging is switched to the lower
coil in order to charge this buffer area.
Buffer
Buffer top Solar
Buffer target solar