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Menu for Anti-legionella function
Line no Description
1640
Legionella Function
1641
Legionella function periodically
1642
Legionella function weekday
1644
Legionella function time
1645
Legionella function setpoint
1646
Legionella function duration
1647
Legionella function circulation
pump
In a return system that has a heat loss of more than 3°C, the temperature reached at the B39
sensor may never be enough to confi rm that the anti-legionella setpoint has been achieved.
For example: If the legionella requirement was for a 70°C setpoint for 1 minute and the heat losses on the return
system were 5°C, The temperature leaving the tank would be at a maximum of 73°C (anti-legionella setpoint +
maximum boost) and this would return to the tank at 68°C. The anti-legionella function would never be satisfi ed in
this scenario and the controls would attempt to achieve the anti-legionella setpoint for a total of 48 hours before
the controls fi nally give up and an error message results.
Alternative solution when return pipe system losses are high and the return sensor is installed
If the return sensor functionality is to be retained, an alternative method to achieve a regular anti-
legionella function would be to set the following:
•
Set "1612 Reduced setpoint" as the normal DHW tank temperature (e.g. 60°C)
•
Set "1610 Nominal setpoint" as the temperature required for an anti-legionella cycle (e.g. 70°C)
•
Set "5070 Automatic push" to OFF
•
Use time program 4 to set the length of time and the day that you want to run your anti-legionella cycle (every
day is recommended) – For guidance on the length of time required please refer to the table below:-
The fi gures given in the table above are for guidance only. The advice given in Approval Code of Practice (ACOP)
L8, "Legionnaires' disease: The control of legionella in water systems", and HSG274 Legionnaires' Disease Technical
Guidance, should be followed."
Commissioning
Factory default Notes
Off
7 days
Sunday
01:00
70
O
C
10 mins
On
Temperature
Time required at setpoint
70°C
1 MINUTE
66°C
2 MINUTES
60°C
32 MINUTES
55°C
6 HOURS
49
Choose to have the legionella function activated on a
fi xed weekday (parameter 1642), every (parameter 1641)
number of days or switch the function off .
No of days before the legionella function will activate
Fixed day the legionella function will activate
Time the legionella function will start
The setpoint to be achieved for the legionella function
The length of time the DHW tank sensors and B39 circu-
lation return sensor (if fi tted) should achieve the setpoint,
before the function is completed. If the legionella func-
tion cannot be performed successfully within a 48 hour
period, an error message will be displayed.
Choose whether the circulation pump Q4 is on or off
when the legionella function is active
MAXXfl o EVO
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