43
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 selec-
ted stores is being loaded and there is a temperature
difference between the sensor of the corresponding
store and the solar flow.
any number of the solar stores can be selected.
the relay is switched off if this temperature diffe-
rence 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.
In systems in which stores are equipped with their
own loading pumps, the relay “external heat ex-
changer“ controls the primary circuit pump.
the heat exchanger is protected by a non-adjustab-
le antifreeze function.
Note:
Because of the special hydraulics, the target
temperature option will not work properly
in systems with 2 collector fields.
adjustment channel Description
adjustment range / selection Factory setting
relay
relay selection
system dependent
system dependent
min speed
minimum speed
30 ... 100 %
30 %
store
sensor selection
system dependent
1
sensor HX
reference sensor ext.HX
system dependent
system dependent
targ. temp.
target temperature option
Yes, no
no
sensor
target temperature reference
sensor
system dependent
system dependent
targ. temp.
target temperature
15 ... 95 °C [60 ... 204 °F]
60 °C [140 °F]
∆
ton
switch-on temperature difference 1.0 ... 20.0 K [2.0 ... 40.0 °ra]
10.0 K [20.0 °ra]
∆
toff
switch-off temperature difference 0.5 ... 19.5 K [1.0 ... 39.0 °ra]
5.0 K [10.0 °ra]
overrun
overrun time
1 ... 15 min
2 min
Solar / Opt. functions / Add new function... / Ext. HX
295931-36390-8667 SOM 8 plus_en.indb 43
20.10.2011 13:14:41