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7
Water to Water Heat Pump (WTW)
Legionella Prevention Mode settings (LP mode)
1. Use button F3 to choose legionella mode active YES/NO.
2. To edit the legionella function, press down the MENU button for 3 sec-
onds and select "hot water", then press F4 key.
3. Use F1 and F2 keys to scroll through the menu selecting each subtitle
in turn by pressing CONFIRM. See the table below for description of
each setting.
4. Enter the desired number using the function keys and press CONFIRM.
During Legionella Prevention Mode the temperature of the stored water is
increased above 60°C to inhibit legionella bacterium growth. It is strongly
recommended that this is done at regular intervals. Please check local
regulations for the recommended frequency of heat ups.
Menu subtitle
Function
Hot water temp.
Desired temp of stored hot water
Frequency
Time between LP mode DHW tank heat ups
Start time
Time when LP mode will begin
Max. operation time
Maximum time allowed for LP mode DHW tank heat
Duration of max. temp. The time period after LP mode max. water temp. has been reached
If you wish to make changes contact installer.
Explanation of Legionella Prevention Mode operation
• At the time entered by the installer 'Start time' flow of use-
ful heat from the system is diverted to heat the water in the
DHW tank.
• When the temperature of the stored water exceeds the 'Hot
Water temp.' set by the installer (above 65°C) primary circuit
water is no longer diverted to heat the DHW tank.
• Whilst LP mode is in operation hot water is not directed to
the space heating circuit.
• Directly after LP mode operation 'Duration of max. temp.' will
operate. The duration of this feature is set by the installer
and during its operation stored water temperature will be
monitored.
• If stored water temperature should drop to LP restart temp.,
LP mode will restart and primary water flow from the heat
source(s) will be directed to the DHW tank to boost the tem-
perature. Once the set time for Duration of Max. temp. has
passed LP mode will not recur for the set interval (set by
installer).
• It is the responsibility of the installer to ensure the settings
for legionella prevention are compliant with local and na-
tional guidelines.
Please note that LP mode uses the assistance of electric
heaters to supplement the energy input of the heat pump.
Heating water for long periods of time is not efficient and
will increase running costs. The installer should give care-
ful consideration to the necessity of legionella prevention
treatment whilst not wasting energy by heating the stored
water for excessive time periods. The end user should un-
derstand the importance of this feature.
ALWAYS COMPLY WITH LOCAL AND NATIONAL GUID-
ANCE FOR YOUR COUNTRY REGARDING LEGIONEL-
LA PREVENTION.
DHW tank temp.
Stop
Stop temp.
Legionella
hot water temp.
Restart temp.
Space
Start
LP mode
heating
(LP mode: Legionella Prevention mode)
Range Unit
Default value
60–70
°C
65
1–30
day
15
0:00–
-
03:00
23:00
1–5
hour
3
1–120
min
30
Stop
Restart
LP
Mode
mode
finish
Time
Duration of
Max. temp.
B-245
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