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Version with SM1 and KM-BUS
Cyclical heating
Set code/parameter "20:9".
In systems with 2 DHW cylinders:
If the DHW cylinder with priority cannot be heated, the
secondary cylinder is heated for a cyclical heating time
that can be set in coding address "27". After this time
has expired, the solar control unit checks the rise in
collector temperature during a cyclical pause time that
can be set in coding address "28".
Version with SDIO/SM1A electronics module and PlusBus
Solar DHW heating
Note
Set or alter the functions described below in the
parameters in the "Solar" group.
The solar circuit pump is switched on according to the
following criteria, resulting in the DHW being heated:
■
The temperature differential between the cylinder
temperature and the collector temperature is greater
than the start temperature differential set in parame-
ter 1492.0.
■
The minimum collector temperature set in parameter
1126.0 is exceeded.
The solar circuit pump is switched off if one of the fol-
lowing criteria is met:
■
The temperature differential between the cylinder
temperature and the collector temperature is smaller
than the stop temperature differential set in parame-
ter 1492.1.
The maximum cylinder temperature (set DHW tem-
■
perature) set in parameter 1125.0 is exceeded.
■
The maximum collector temperature set in parameter
1126.1 is exceeded.
■
The temperature set at the high limit safety cut-out is
exceeded.
(cont.)
As soon as the start conditions for the cylinder with pri-
ority are met, that cylinder is heated again. Otherwise,
the secondary cylinder continues to be heated.
Coding addresses "26", "27", "28".
Suppression of DHW cylinder reheating by the
boiler
Reheating is suppressed in 2 stages:
Reheating of the DHW cylinder by the boiler is sup-
■
pressed as soon as the DHW cylinder is heated by
the collectors. For this, the set DHW temperature for
reheating by the boiler is reduced. Suppression
remains active for a certain time after the solar circuit
pump has stopped.
■
When the collectors provide continuous heating
(
2 h):
>
The DHW cylinder will only be heated by the boiler if
the third set DHW temperature is not achieved by the
solar thermal system.
The third set DHW temperature is specified by
parameter 1394.0 in the "Solar" group. This value
must be below the first set DHW temperature.
Maximum collector temperature
If the maximum collector temperature set in parameter
1126.1 is exceeded, the solar circuit pump is switched
off to protect the system components (emergency col-
lector shutdown).
The solar circuit pump will restart when the collector
temperature falls to 20 K below the set value.
Minimum collector temperature limit
The solar circuit pump is started when the minimum
collector temperature set in parameter 1126.0 is
exceeded.
Reduction of stagnation time
If there is an excess of solar energy, the speed of the
solar circuit pump is reduced before the maximum cyl-
inder temperature is reached (parameter 1125.0). This
causes an increase in the differential between collector
temperature and cylinder temperature. The heat trans-
fer to the DHW cylinder is reduced, which delays stag-
nation.
Function description
27
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