Thermal Disinfection Of The Dhw Storage Tank - Samson TROVIS 5573 Mounting And Operating Instructions

Functions of the DHW circuit
6.10

Thermal disinfection of the DHW storage tank

In all systems with DHW heating, a thermal disinfection is performed on a selected Day of the
week or every day.
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In systems with DHW storage tank, it is heated up, taking into account the Charging tempe-
rature boost parameter (or Set point boost , depending on the system) to the adjusted Disin-
fection temperature . Disinfection begins at the adjusted Start time and, at the latest, ends at
the specified Stop time .
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In systems with DHW heating in instantaneous heating system, the function remains active
taking into account the Set point boost parameter until the circulation pipe, measured at
SF1, has reached the adjusted Disinfection temperature, provided disinfection has not been
terminated because the Stop time has been reached.
The Hold time of disinfection temperature determines how long the disinfection temperature
must be maintained within the adjusted time period to rate the process successful. If the Hold
time of disinfection temperature is set to a value other than 0, no intermediate heating opera-
tion takes place during thermal disinfection.
If the Start time and Stop time are set to the identical time, disinfection is controlled depending
on the switching state of the binary input (terminals 03/12) to be performed daily or on the pro-
grammed day of the week: disinfection starts optionally with a break contact (bE=0) or a make
contact (bE=1). It stops at the latest when the switching state of the binary input next changes.
When the Disinfection temperature has not been reached before the end of the thermal disin-
fection cycle, an "Err 3" error message is generated. This error message can also be generated
prematurely if the remaining time until the disinfection temperature is reached is shorter than
the adjusted Hold time of disinfection temperature . The error message is automatically reset
when the Disinfection temperature is properly reached during the following thermal disinfec-
tion cycle.
Thermal disinfection for preventing legionella infection causes:
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excessively high return flow temperatures during the disinfection cycle (return flow tempera-
ture limitation suspended),
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excessively high DHW temperatures after thermal disinfection has been concluded,
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lime scale (possibly), which can have a negative effect on heat exchanger performance.
Note: This function is not available when a storage tank thermostat is used.
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EB 5573 EN