en
47
Solar external heat exchanger
This function is used to link loading circuits that are
separated by an external heat exchanger.
The allocated relay is energised if one of the selected
stores is being loaded and there is a temperature dif-
ference between the sensor of the corresponding
store and the solar fl ow.
Any number of the solar stores can be selected.
The relay is switched off if this temperature difference
falls below the adjusted switch-off difference.
In contrast to the bypass function, a differential con-
trol between Sensor HX and the store temperature
can be carried out by means of the heat exchanger
relay.
The reference sensor can be arbitrarily allocated.
When the Target temperature option is activated, the
pump speed control logic changes. The controller will
remain at the minimum pump speed until the tem-
perature at the allocated sensor exceeds the adjusted
target temperature. Afterwards, speed control of the
heat exchanger will start.
In systems in which stores are equipped with their
own loading pumps, the relay “external heat exchang-
er“ controls the primary circuit pump.
The heat exchanger is protected by a non-adjustable
antifreeze function.
Note:
Because of the special hydraulics in systems
with 2 collectors, the target temperature
function will not work properly there.
Adjustment channel Description
Adjustment range / selection Factory setting
Relay
Relay selection
system dependent
system dependent
Min speed
Minimum speed
30 ... 100 %
30 %
Store
Store sensor selection
system dependent
all stores
Sensor HX
Reference sensor ext. HX
system dependent
system dependent
Target temperature Target temperature option
Yes, No
No
Sensor
Target temperature reference sensor system dependent
system dependent
Targ. temp.
Target temperature
15 ... 95 °C
60 °C
∆
Ton
Switch-on temperature difference
1.0 ... 20.0 K
10.0 K
∆
Toff
Switch-off temperature difference
0.5 ... 19.5 K
5.0 K
Overrun
Overrun time
0 ... 15 min
2 min
Solar / Opt. functions / Add new function / Ext. HX