Protective Functions - Riello SC ACS 40 Manual

Settings range: 10 °C to 85 °C
4.4.3 Recirculation hysteresis - switch-off hysteresis of the circulation pump
If temperature exceeds Tmin at S2, the pump is switched off.
Settings range: 1-5K / Default: see table.
4.4.4 Maximum recirculation flow - maximum fl ow rate of the circulation pump
If the flow rate measured at sensor 6 exceeds this value (because water is being drained from the system) the circulation
pump is switched off.
Settings range: 1-50 l/min.
b
This value is set during system calibration.
4.4.5 Recirculation periods - period where the circulation pump is enabled
Set the operation times of the circulation pump. 3 different periods can be set for every weekday, which can also be cop-
ied to other days. Settings range: Off/ 00:00-23:59 / Default: 06:00 ... 20:00 h.
b
This settings 4.4.5. are only available if circulation mode "Periods" or "Request + Time" is choosed.
b
Recirculation is disabled outside these time bands. The time settings are only used in "Periods" recirculation mode.
4.4.6 Draw-off support
To ensure a constant temperature even when small volumes of water are drawn off, the recirculation pump can also be
used to assist draw-off.
The pump runs under normal conditions and when small volumes are drawn off.
If a storage cylinder sensor is connected, draw-off support is enabled when this sensor detects Tmin.
Settings range: On, Off / Default: On.
Min storage cylinder Temp.: Setting range_ 0..... 80°C
4.4.7 Minimum storage temperature
Tap support is deactivated when the storage temperature drops below „Min storage temp".
4.4.8 Draw-off support measuring
See "Calibration".
4.6 Storage stratification
The storage stratification function operates a valve that deviates the return to the centre or bottom of the storage cylinder
on the basis of temperature. This menu sets the temperature differential between the return and the storage cylinder. If
return temperature exceeds storage temperature by the value set here, the central part of the storage cylinder is buffered.
If no storage sensor is connected, storage temperature is set at 25 °C.
4.11 Comfort
When this function is active, the primary circuit pump pumps water through the heat exchanger every 15 minutes to en-
sure that hot water is delivered as rapidly as possible when water is drawn off.

5. PROTECTIVE FUNCTIONS

Menu "5. - Protections / Protective functions" can be used
to set and activate a number of protective functions.
To quit the menu, press "esc" or select "Exit Protective
functions".
b
This does not under any circumstances replace the
safety facilities to be provided by the customer!
5.1 Anti-legionella
With the AL function activated, the MFWC 3 controller
heats the pipes and the storage cylinder at selectable pe-
riods (AL period) for a set time (AL residence time), until the target temperature setpoint (AL Tset) is reached.
AL Tset + 5 °C is taken as the reference for the temperature measured at S5. For the period during which the AL function
is active, Tmax is set at AL Tset + 10 °C to prevent shut-down for high temperature. The AL function terminates only when
a temperature of at least "AL Tset - 5 °C" is reached at the hot water sensor and at the recirculation sensor (if installed) for
the time set in "AL residence time". The "Last AL heat" is shown on the display. If the AL function fails to terminate after 2
hours, the function is cancelled and an error message is displayed.
AL function – Settings range: On, Off / Default: Off.
AL run time
AL Tset
AL Period
AL residence time
Manual start – starts a heating cycle immediately
b
During the Anti-legionella function the storage cylinder is heated to high temperatures that can lead to scalding and
damage to the system.
b
The user must make sure that the Anti-legionella function terminates successfully at the set periods.
5.Exit protective functions
5.1.Anti-legionella
5.2.Limescale protection
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