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Functions for boiler control
The functions for boiler control are accomplished
via the potential-free relay contact which is connected
accordingly to the relevant interface of the heating boiler.
The individual functions are assigned
the following priorities:
A Anti-legionella priority 1
B recharge suppression priority 2
C reheating priority 3
Boiler
Anti-legionella function
The anti-legionella functions checks if the minimum heating for reduction of legionella
has been achieved in the tank due to heating activity or solar heat within a set interval.
If no sufcient heating has been achieved by these means the controller starts a reheat
cycle, specically for reduction of legionella.
The tter must set the parameters based on the applicable general directives and local
requirements. The time of the disinfection cycle can be determined freely.
Reheat function
The temperature sensor in the upper tank area supplies the values for reheating.
For oil or gas operated systems, reheating takes place via the heating boiler.
For solid-fuel boilers, reheating takes place via the heat present in the drinking water
tank. To this effect, the temperature within the tank must be within preset limits.
The temperature control is interlinked with six time blocks.
Reheating is activated as soon as the temperature falls below
the set value by the hysteresis value in the current time block.
When the set value is exceeded the reheating cycle stops.
Disable recharge
The efciency of a solar plant increases as the recharge of the tank from the
boiler decreases. Consequently, „disable recharge“ means that
recharging of the water tank is blocked by the boiler.
Time-controlled disable recharge
Recharge is blocked by the boiler for specic phases via a time program.
Within the preset period of time (for ex. 7 to 19 h), recharge is blocked completely
by the boiler without requiring the minimum temperature to this effect.
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