Service manual

28 AWR MTD - AWR MTD/B GB 01/2009
Outlet water temperature (°C)
Outside air temperature (°C)
-15-20 -5 7 45
50
40
55
Heaters
only
Heat pump
ON
ON
OFF
OFF
Spw -6°C
Spw -3°C
Spw
Spw = Water set point
[ºC]
[ºC]
1st stage enabled
2nd stage enabled
Exchanger inlet water temperature
Heaters as replacement source (factory configuration)
The electric heaters are activated to replace the compressor if its operating limits are exceeded, see the graph.
Electric heater management
Parameter Value Description
HI20 3 Enable heaters as replacement
HI25 3 1st heater stage hysteresis
If the Anti-Legionella cycle is not completed, the display shows a warning. Contact an authorised service centre.
Parameter Value Description
AS06 3 Domestic hot water heater hysteresis for Anti-Legionella
AS20 70 Anti-Legionella set point
AS34 1h Anti-Legionella cycle duration for Thursday
AS35 2 Anti-Legionella cycle start hours for Thursday
AS36 0 Anti-Legionella cycle start minutes for Thursday
ANTI-LEGIONELLA FUNCTION
The Anti-Legionella function ensures the elimination of the Legionella bacteria that reside in domestic water vessels; such bac-
teria typically die when the water temperature is above 70°C.
The Anti-Legionella function must be activated by an authorised technician.
This function is only available if an electric heater is fitted inside the DHW storage (see the function "DHW storage
heater").
If the Anti-Legionella function is active, the domestic hot water is heated to 70°C for at least 60 minutes each Thursday of the
week, starting at 2 am.
Deactivation of the Anti-Legionella cycle
The Anti-Legionella cycle ends if at least one of the following conditions is satisfied:
• the DHW storage temperature (sensor BT4) reaches the Anti-Legionella set point, parameter AS20
• the Anti-Legionella time has terminated, parameter AS34.