STIEBEL ELTRON Accelera 300 E - Manual (Page 13)

OPERATION
Settings
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If the relevant set DHW temperature is accomplished, the com-
pressor switches off and remains off for a minimum idle time of
20 minutes.
The following diagram illustrates the connections by means of a
sample signal sequence of an external signal transmitter.
Example:
- DHW temperature = 131°F /55°C)
- Set temperature 1 = 124°F/ 50°C)
- Set temperature 2 = 149°F /65°C)
A
1
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 t [min]
B
1
1
0 2
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 t [min] D00000
346
13
A LF signal
B Compressor
1 20 min. minimum runtime, set temperature 2
2 20 min. minimum compressor idle time
Note
An LF signal must be active for at least 60 seconds before
the control unit responds to it. This prevents cycling of the
compressor due to fast changing sun radiation condition.
4.3 Calling up fault codes
Based on the set temperature 2 menu,
press the menu key once to get to the
fault code menu. A fault code will appear
if a fault has occurred. If no error has
occurred, this menu is not available.
See 6.1, “Fault codes”, pg. 15 .
4.4 Rapid heating key
Press the rapid heating key.
The heat pump and electric booster ele-
ment symbols appear.
4.4.1 Comfort heating
Normally, the rapid heating key is used to activate the comfort
heating function, which enables the water heater to satisfy an
unexpectedly high DHW demand without changing any of the ap-
pliance's standard settings.
When comfort heating is activated by pressing the rapid heating
key, the heat pump and the electric booster element will start
in parallel, irrespective of the selected set temperature. To save
energy, the electric booster element switches off as soon as a
temperature of 149°F/65°C has been achieved in the upper tank
section (rapid heating).
The heat pump remains on and the comfort heating function re-
mains active until a temperature of 149°F/65°C) has been achieved
in the entire DHW tank (comfort heating). The appliance then au-
tomatically switches back to the previously set parameters.
Note
The electric booster element and heat pump symbols are
displayed until the comfort heating function has termi-
nated.
During comfort heating, the electric booster element
symbol is displayed until the heat pump has heated the
entire tank to 149°F/65°C and the function is terminated,
e ven though t he electric booster element switches off
when the 149°F/65°C) has been achieved in the upper
tank section.
Note
If comfort heating has been activated, it can be canceled
by reducing the set temperature.
  Hold down the minus key, until you hear a clicking
noise caused by the heat pump and booster heater
switching off. The set temperature will jump back to
the value that was selected before comfort heating
was activated.
4.4.2 Emergency back up mode
If the heat pump is out of order, it is possible to use the electric
booster element in back up mode to ensure hot water production.
The electric supply to the compressor shuts down if the water
temperature increase is less than 0.5°F/0.25°C) in a time frame
of 13 hours. In this case the fault code is activated and will fl ash.
The fault key fl ashes on the display and a fault code indicates that
the appliance is not heating the water.
To activate the backup mode, press the rapid heating key. After
the rapid heating key has been pressed, the indicated fault code
increases by a value of 256, as the fault codes are summed to-
gether (See 6.1, “Fault codes”, pg. 15). The fault key continues
to fl ash. The electric booster element is activated.
The current set temperature (set temperature 1 or set tempera-
ture 2) is ignored. In emergency mode, the appliance operates
with a fi xed set temperature of 104°F/40°C). After a one-off ac-
tivation of the function via the rapid heating key, this function
remains active for 7 days.
Following 7 days of backup operation, the electric booster element
is deactivated. The fault code shown on the display decreases by
256.
If the rapid heating key is pressed again within the 7 days of
backup operation, the 7-day run time for emergency mode will
start afresh from that point.
Pressing the rapid heating key only activates backup mode if a
fault with fault code 8 occurred previously. In standard mode
pressing the rapid heating key only triggers a one-off heating of
the DHW tank for a single instance.
An interruption of the power supply will disable the back up mode
immediately. The heat pump will try to heat again for a duration of
13 hours after the power outage. After 13 hours without a water
temperature increase, the fl ashing service key occurs again and
the back up function may be activated.