47
4.2.4
Plate heat exchanger, buffer tank with fresh water function
If, in the 'System
selection'
menu, the points "Plate
heat exchanger", "Buffer
tank with ...",
"Fresh water funct." and
"Basic" are selected,
the
hydraulic diagram
illustrated here is
available for use as a
basic system (basic) with
the indicated variants.
•
"Basic" system: The regulator constantly records the differential temperature between the sensors
T1 and T2. If the set switch-on differential temperature (parameter: 'diff. temp. solar ON') is
reached, the solar circuit pump R3 switches on and heats the solar circuit with the plate heat
exchanger. If the temperature level on the plate heat exchanger T3 reaches a value of at least 5
Kelvin more than the 'Lower part of the storage tank' temperature T2 and if T3 is at least 3K above
the parameter value “AH extern. threshold “ (charging below this value could otherwise lead to
unintentional activation of any installed external after-heating), R1 switches on with minimum speed
and then regulates the temperature of the charging current at the preset value (parameter: 'Preset
charging temp.'). This happens as long as either the maximum storing temperature (parameter:
''storage max.') is reached or the differential temperature between T3 and T2 falls below a value of
3 Kelvin. The solar circuit pump R3 remains active until either the maximum storing temperature
(parameter: ''storage max.') is reached or below the switch-off differential temperature of the solar
circuit (parameter: 'diff. temp. solar OFF'). To protect the charging circuit from overheating, the
solar circuit is deactivated when T3 is only 3 Kelvin below the maximum charging temperature
(parameter: 'Max. charging temp.'). If the charging circuit continues to heat up because of an
erroneous function, R1 is also deactivated when the maximum charging temperature is reached.
Important: The control device for the fresh water function is not linked in the diagram. This
must be activated in the menu Service
→
Functions
→
“Fresh water at R2” (
-->
:
).
Settings: The temperature, which should be reached on the warm-water side, should be entered as
the aim temperature. In the present diagram, the sensors must be set as follows: “Target temp. at:
E6 (regulator)“ and “Feed line/st. upp.: E4 (regulator)“.
The additional values should not be changed in any event!!!
By controlling the speed of the "discharge pump" the solar regulator attempts to maintain the "hot
water temperature" – irrespective of the volume flowing in the hot water pipe – at a constant
temperature (Functions
→
Fresh water at R2
→
"aim temperature") at the extraction points. If the
"upper part of the storage tank" temperature falls below the value "aim temperature" + 5 Kelvin, the
"aim temperature" is internally lowered by 5 Kelvin. This should prevent the storage tank from
mixing. If the "Upper part of the storage tank" temperature again rises above the value "aim
temperature" + 5 Kelvin, the "aim temperature" is internally increased again by 5 Kelvin. If the
temperature at T4 falls below the set "Min. storage tank temp.", the discharge circuit pump is
switched off. This means the control system is idle and will first become active again at values
greater than the "Min. storage tank temp.".
The additional functions shown (charging zones and after-heating) are not activated.
Warning: The parameter value “AH extern. threshold” is factory set to 0°C. This corresponds with
the setting when no after-heating system is connected. If after-heating (e.g. heating cartridge) must
be installed in your system, the parameter “AH extern. threshold” must be set accordingly.
•
Add-on
"
- AH": R4 and T4 combined with an oil or gas boiler can provide after-heating. A detailed
functional description of this add-on can be found on page 15.
R3
T3
R1
T2
storage
tank 1
M
R4
R2
HW
CW
T6
R4
oil,
gas
Basic-AH
Basic
-CZ
T4
T5
if so with
external
after-heating
