Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 10 DHW heating 2017-09-29
If, during the period of time the legionella protection program is performed, the storage
tank temperature (or both storage tank temperatures) can be kept at the required
setpoint, the legionella function will be ended.
If, in addition, consumer control with a circulating pump has been configured, the
consumer’s flow temperature sensor is also required to acquire the legionella protection
setpoint for the legionella protection period. If the circulating pump is switched off
during the time the legionella function is active, consumer control will be exempted from
legionella protection.
The legionella function is ended only when, during the time of legionella protection, all
temperatures have been at their legionella protection setpoint, or above it.
TDhwSetpt
TDhwSetpt - SDDhw
TDhwSetpt - SDDhw - 2 K
ON
OFF
ON
OFF
TDhw
t
3133D09
3
1
2
TiLegioHld
TiLegioHld
SDDhw
Switching differential DHW heating
t
Time
TDhw
DHW temperature
TDhwSetpt
DHW temperature setpoint
TiLegioHld
Holding time of legionella function (period of time legionella protection is provided)

Circulating pump

Enabling the legionella function

Start conditions for legionella function satisfied
During the time the legionella program is active, the circulating pump continues to
operate as preselected.
The circulating pump can be specifically activated to become included in the legionella
function. For that purpose, parameter "Circulating pump operation legio" is used. If this
parameter is set to "On", the circulating pump will operate according to characteristic
1
in the graph above. Exception is direct DHW heating (plant type DHW 6). With this type
of plant, the circulating pump always runs, independent of the flow temperature.
If the circulating pump operates due to the preselection made, it will continue to run
during the time the legionella program is performed, independent of the DHW
temperature.
During the time the legionella program is active, function "Charging time limitation" will
also be active.
The legionella function is monitored to see if it can be successfully completed within 48
hours. Successful means that the legionella protection setpoint (minus switching
differential) could be maintained without interruption, also at the optional sensors
(storage tank sensor at the bottom, consumer’s flow temperature sensor).
If the legionella protection setpoint cannot be maintained, or not for the required period
of time, a fault status message will be delivered:
Number
Text
Effect
2101 Legionella protection error
Message must be acknowledged.
Error disappears only when the legionella
program has been successfully completed
Ending the legionella
program
Supervision