eta PelletsCompact33-50 kW, Operation

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[Solar] function block ETAtouch controller
5.7 [Solar] function block
Overview of the solar heating system
1 Operating condition and information.
A description of the operating conditions can be
found in the integrated Help menu by pressing the
button.
2 Collector temperature
3 Solar heating system consumer.
Currently, the hot water storage tank is loaded from
the solar heating system with a flow temperature of
74 °C. The second buffer consumer is not currently
charged.
The solar heating system control principle
The ETA control principle for solar heating systems is
defined so that an adjustable temperature difference
between the panel and the tank (or the upper and
lower buffer area in a buffer with 2 internal coils) is
complied with. This is done by adjusting the speed of
the solar pump.
Manual switching between "High Flow" (high speed at
a lower collector temperature) and "Low Flow" (low
speed at a higher collector temperature) is not
necessary, because this is automatically controlled.
The ETAtouch control system is compatible with a
great many versions, for enabling the integration of a
solar heating system. The various versions are
described below.
5.7.1 Solar heating system with one tank
Solar heating system with only one tank
The solar heating system is controlled by switching the
collector pump on and off. This is switched on as soon
as the collector has exceeded the minimum
temperature [Collector min] and is warmer by the
difference [Switch-on diff.] (factory setting 7 °C) than
the tank being charged.
Fig. 5-56: Solar heating system connected to buffer
The speed of the collector pump is controlled in
such a way that the collector supplies a
temperature that is higher than the current tank
temperature by the configurable offset [Target
collector diff.].
When the tank has reached its maximum temperature
(the factory setting of the buffer is 90 °C, and the hot
water tank 60 °C), or if the collector is only warmer by
the offset [Switch-off diff.] (factory setting 5 °C) than
the tank, the collector pump is switched off.
Example:
Buffer temperature [Buffer bottom Solar]: 45 °C
[Target collector diff.]: 10 °C
[Switch-off diff.]: 5 °C
=> The speed of the solar pump is adjusted, so that the
temperature on the collector reaches 55 °C. With the
increase in buffer temperature, the collector
temperature also increases, because the 10°
difference is adhered to.
If the collector temperature cannot be increased
(because the sun provides too little heat), the collector
pump switches off when there is only a 5 °C difference
between the collector and the buffer. Otherwise, the
buffer is charged to the maximum temperature of 90
°C.