Installation Instructions
Description of functions
Installation instructions VRC 470f 0020124645_00 35
8
If the temperature difference between the collector and
the cylinder exceeds the preset switch-on difference, the
solar pump runs for an appropriate length of time to
heat up the cylinder (difference control).
8.6.14 Setting the solar circuit protection
Menu ¬ Installer level ¬ System configuration
[Solar ----] ¬ Solar circuit prot.
Only with a connected VR 68/2
With this function, you can define a temperature thresh-
old for the calculated collector temperature in the solar
circuit. If the available solar heat exceeds the current
heat requirement (e.g. all cylinders fully charged), the
temperature in the collector array may rise steeply.
If the protection temperature set at the collector sensor
is exceeded, the solar pump is switched off to protect
the solar circuit (pump, valves, etc.) against overheating.
The solar pump is switched back on once the system has
cooled down (30 K hysteresis).
In combination with a VMS solar station, the setting
parameters are hidden. The solar station has its own
protection function, which is always active.
8.6.15 Defining the maximum temperature for the
solar cylinder
Menu ¬ Installer level ¬ System configuration
[Solar ----] [Solar cylinder 1/2 ----] ¬ Max. tempera-
ture
Only with a connected VR 68/2
This function allows you to define a maximum value as a
limit for the solar cylinder temperature, in order to guar-
antee the highest possible gain from the solar cylinder
heating, but also to ensure protection against calcifica-
tion.
The maximum value of cylinder sensors SP1 and SP2 is
used for the measurement.
For the second cylinder (swimming pool) cylinder sensor
TD1 is used.
If the set maximum temperature is exceeded, the con-
troller switches the solar pump off.
Solar charging is only enabled again once the tempera-
ture at the active sensor drops 1.5 K below the maximum
temperature.
The maximum temperature can be set separately for
each cylinder.
The programmed maximum temperature must not
exceed the cylinder's maximum permissible water tem-
perature!
8.6.16 Defining the on temperature difference value
for solar charging
Menu ¬ Installer level ¬ System configuration
[Solar ----] [Solar cylinder 1/2 ----] ¬ On temp. diff.
Only with a connected VR 68/2
This function allows you to define a difference value for
starting solar charging. If the temperature difference
between cylinder sensor SP2 and collector sensor KOL1
exceeds the set value, the controller switches the solar
pump on and the solar cylinder is charged.
The difference value can be defined separately for two
connected solar cylinders.
8.6.17 Defining the off temperature difference value
for solar charging
Menu ¬ Installer level ¬ System configuration
[Solar ----] [Solar cylinder 1/2 ----] ¬ Off temp. diff.
Only with a connected VR 68/2
This function allows you to define a difference value for
stopping solar charging. If the temperature difference
between cylinder sensor SP2 and collector sensor KOL1
falls below the set value, the controller switches the
solar pump off and the solar cylinder is no longer
charged.
The off temperature difference value must be at least 1K
less than the set on temperature difference value. There-
fore the value for the setting difference is automatically
adjusted when 1 K is exceeded.
You can define the difference value separately for two
connected solar cylinders.
8.6.18 Defining the on temperature difference value
for second difference control
Menu ¬ Installer level ¬ System configuration
[Solar ----] [2nd Difference control ----] ¬ On temp.
diff.
Only with a connected VR 68/2
This function allows you to define a difference value for
starting solar support.
If the temperature difference between cylinder sensor
TD1 and temperature sensor TD2 in the return of the
solar circuit exceeds the set value, the controller acti-
vates output MA ( Multi relay).
This function is only effective if "diff. ctrl." is selected
when setting the multi relay (¬Section8.6.12
).