9
5. Control system
1) Based on the physical fact that the existing heat
energy in the heat transfer unit has to be controlled
by the control system, short-term temperature
fluctuations at the start of a hot water tapping
cannot be ruled out completely. Favourable control
behaviour is achieved with the water temperature –
cold function, which results in very short or no
reheating time!
2) The plate heat exchanger is kept hot by the heat
exchange media from the buffer. The heat exchange
media can take on temperatures of more than 60°C.
Please note that such temperatures can result in
calcium oxide precipitation!
5.3.4 Manual operation menu
QThe output 1, output 2, output 3 and outputs
„overall test” can be switched on and off manually,
in order to check the functioning of the pumps.
QCharacteristic curve calibration
Here the regulation of the characteristic curve is
determined during the initial operation. (See 6.3.2)
QCirculation adjustment
In this menu item the circulation adjustment is
carried out.(See 6.3.3)
5.3.5 Basic setting menu
This menu contains important technical information and
parameters for controlling, which may be modified by
a specialist tradesman. In order to modify values, the
submenu “release” in the basic setting menu has to be
activated. (See 8)
QInformationen
Here information regarding the software and system
version is given.
QController ON/OFF 3)
Amongst other things, this menu item contains the
safety shutdown for a domestic hot water tempera-
ture of 60°C. Should this temperature be exceeded
at T1, pump P1 switches off until the temperature
drops to below 60°C. This value should be increased
when the hot water – set value is increased.
However, a blending valve should additionally be
mounted on the domestic hot water outlet of the
freshwater station. The other control parameters
should not be adjusted!
QPulse generator 2)
These values are used to adapt the flow rate
generator at the control system.
QCharacteristic curve 2)
In this menu item the pre-determined operating
points of the control system can be read.
In this menu item the pre-determined operating
points of the control system can be read. Likewise
the default value for flow max. of the characteristic
curve calibration can be modified. Should, for
example, the 25l/mm for the characteristic curve at
flow max. not be reached, the default value for flow
max. can be lowered to 15l/mm. (See 6.3.2)
QHeat transfer unit
After run 2)
Outside the circulation time and after a drawing off of
hot water, it is possible to keep the circulation pump
running afterwards. The stainless steel plate heat
exchanger is cooled down and its decalcification is
counteracted. The function of the after-run, from an
energy point of view, is only meaningful and possible
outside the circulation time!
QCirculation ON/OFF
If this function has been activated, up to three time
slots can be set in the „programming” menu.
In the time slot, controlling is always based on the
circulation temperature. If the time slot has ended, or
drawing off takes place or the circulation temperature
has been reached, the circulation switches off. It is
attached to the circulation rest time. No circulation
can be activated in the circulation rest time. To avoid
the heat transfer media in the buffer from being
mixed, the heat transfer media temperature is
checked at the heat transfer media- flow- sensor
T2 or with the option at T5 at the start of the circula-
tion process, to ensure that the heat transfer media
temperature is greater than the circulation set
temperature +2K. This happens at T2 with the
following procedure: The heat transfer pump P1 runs
for 5 minutes at minimal capacity. Should the
circulation set temperature plus 2K not be attained
after expiry of the 5 minute run time, the heat
transfer pump P1 is switched off – and restarts the
process again after a waiting period of one hour.
Following this, the flashing message „error
message flow temperature” will be seen on the
display in the information menu.
Flow increase 5 K
In some cases (high temperature drops in circula-
tion capacity), the circulation return temperature is
not reached. The set value of the circulation tempera-
ture (flow increase 5K) can be increased up to 20 K.
The input is limited to the hot water set temperature
value. Should the hot water set temperature be
reduced, the flow increase value for circulation is
also reduced!
Example:
Circulation set = 35°C, hot water set = 50°C, flow
Increase = 15 K possible
Circulation set = 40°C, hot water set = 50°C, flow
Increase = 10 K possible
Circulation set = 40°C, hot water set = 45°C, flow
Increase = 5 K possible
