76
12.8.5 A
NTI
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LEGIONELLA PROTECTION
Anti-Legionella protection is enabled for DHW modes with an external tank with a sensor (DHW Mode 1) or for the
direct fired water heater (DHW Mode 6 & 7) and when DHW is not switched OFF.
To prevent legionella a special function is implemented in the software.
• When DHW Mode 1 is selected the Anti-Legionella protection will be checked on the T_DHW_Out sensor.
• When DHW Mode 7 is selected the Anti-Legionella protection will be checked on the T_Supply sensor.
• When DHW Mode 6 is selected the Anti-Legionella protection will be checked on the Top_Store_1 sensor. This
sensor will be named the Anti_Legionella_Sensor in the remaining part of the explanation.
At least once every 168 hours (7 days) the Anti_Legionella_Sensor must reach a temperature above
Anti_Legionella_Setpoint for a time specified by Anti_Legionella_Burn_Time.
If 7 days have passed and these conditions are not met, the boiler is forced to heat-up the system for Anti-Legionella.
When the Anti_Legionella_Sensor temperature is below Anti_Legionella_Setpoint the control switches ON the
pumps, when the Anti_Legionella_Sensor temperature is above Anti_Legionella_Setpoint 5 °C (41 °F) the control
stops the pumps.
When DHW Mode 1 is selected the boiler setpoint will be at Anti_Legionella_Se DHW_Store_Supply_Extra,
for DHW Mode 6 and DHW Mode 7 the burner setpoint will be at Anti_Legionella_Setpoint.
If the supply temperature drops below the Boiler_Setpoint the boiler is started as well. The boiler is PID controlled
towards the Boiler_Setpoint. When the supply temperature rises above boiler se DHW_Supp_Hysterese_Up
the boiler is switched OFF.
When the Anti_Legionella_Sensor is above Anti_Legionella_Setpoint 3 °C (37 °F) for Anti_Legionella_Burn_Time
the controller goes into post circulation and ends the Anti-Legionella demand. When the controller has powered up,
the Anti_Legionella_Sensor temperature must reach a temperature of Anti_Legionella_Setpoint (for
Anti_Legionella_Burn_Time) within 2 hours, otherwise the boiler is forced into Anti-Legionella demand.
Every time an Anti-Legionella demand has ended the Anti_Legionella_Active_Counter is incremented to indicate
how many Anti- Legionella actions have been performed. Also, the Anti Legionella Wait Time is started to delay the
next anti legionella cycle.
This diagnostic tool can also override the wait time for Anti-Legionella. When this demand is forced the timer will be
set to 0 and Anti-Legionella demand will start immediately. Then the demand must be completed successfully before
the wait timer is set again.
The anti-legionella demand has priority over any DHW and CH demand. However, when the anti-legionella
protection is active and there is no heat or burn demand because the Anti_Legionella_Sensor is already at a high
enough temperature CH/DHW demand will be accepted as normal.
Parameters are factory set
Parameter
Factory Setting.
Anti_Legionella_Setpoint
Setpoint for Anti-Legionella demand
60 ºC (140 ºF)
Anti_Legionella_Burn_Time
30 Min.
Anti_Legionella_Wait_Time
Wait time for Anti-Legionella demand.
120 min after cold start, 168 h after first successful Anti-Legionella demand
Summary of Contents for S-CBX 105
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Page 40: ...40 9 10 Flue Terminal Positioning ...
Page 42: ...42 9 11 1 FIGURE 12 LINE G ...
Page 55: ...55 11 5 Ladder Logic Diagram ...
Page 56: ...56 11 6 Electrical schematics ...
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