Tank temp.
DHW mode
DHW mode
Time
DHW max.
temp.
DHW max.
temp.drop
Stop
Start
Restart
Tank temp.
DHW max.
operation time
DHW mode
restriction DHW mode
Time
DHW max.
temp.
DHW max.
temp. drop
Stop
Stop
Start
Restart
Customising Settings for your Home
4
Domestic Hot Water (DHW) / Legionella Prevention
The hot water and legionella prevention menus control the operation of domestic
hot water tank heat ups. They are not available if your system uses the hydrobox
with no cylinder.
When DHW screen is displayed pressing button F changes between Normal
and Eco DHW modes. Pressing button F3 activates/deactivates Legionella Pre-
vention mode.
Menu subtitle
Function
range
Unit
default value
DHW max. temp
Desired temperature of stored hot water
40–60
°C
50
DHW max. temperature
drop
Difference in temperature between DHW max. temp and the temperature at which DHW
mode starts
5–30
°C
0
DHW max. operation time
Max time allowed for stored water heating DHW mode
30–20
min
60
DHW mode restriction
The time period after DHW mode when space heating has priority over DHW mode tem-
porarily preventing further stored water heating
(Only when DHW max. operation time has passed.)
30–20
min
30
if you wish to make changes contact installer.
<explanation of dHW operation>
When the tank temperature drops from “DHW max. temp” by more than the
“DHW max. temperature drop” (set by installer), DHW mode operates and the
flow from the primary heating circuit is diverted to heat the water in the storage
tank.
When the temperature of the stored water reaches the ‘DHW max. temp’ set
by the installer or if the ‘Max operation time’ set by the installer is exceeded
DHW mode ceases to operate.
Whilst DHW mode is in operation hot water is not directed to the space heating
circuit.
Directly after DHW mode operation ‘DHW mode restriction’ will operate. The
duration of this feature is set by the installer and during its operation DHW
mode can not be reactivated allowing time for primary hot water flow to be di
-
rected to the space heating circuit if necessary.
After the ‘DHW mode restriction’ operation the DHW mode can operate again
and tank heating will continue if needed.
<eco mode>
DHW mode can run in either ‘Normal’ or ‘Eco’ mode. Normal mode will heat the
DHW tank quickly using the full power of the heat pump. Eco mode takes a little
longer to heat the tank but the energy used is reduced as the heat pump opera-
tion is restricted using signals from the FTC3 based on measured tank tempera-
ture.
Note:
The actual energy saved in Eco mode will vary according to outdoor temperature.
<Forced dHW>
The forced DHW function is used to force the system to operate in DHW mode. In
normal operation the water in the DHW tank will be heated either to the set tem-
perature or for the maximum DHW mode time, whichever occurs first. However
should there be a high demand for hot water the ‘Forced DHW’ function can be
used to prevent the system switching to space heating and continue to provide
DHW tank heating
Forced DHW mode is activated by pressing button F when option screen is dis-
played.
•
•
•
•
•
Legionella prevention mode (LP mode)
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 up cycles.
Note: If failures occur on the cylinder unit the LP mode may not function normally.
Menu subtitle
Function
range
Unit
default value
Hot water temp.
Desired temp of stored hot water
60–70
°C
65
Frequency
Time between LP mode tank heat ups
–30
day
5
Start time
Time when LP mode will begin
0:00–23:00
-
03:00
Max. operation time
Maximum time allowed for LP mode tank heat
–5
hour
3
Duration of max. temp.
The time period after LP mode max. water temp has been reached
–20
min
30
if you wish to make changes contact installer.
