8
Cooling functions
Different cooling functions can be activated: system cooling, store cooling and heat
dump.
Note
If the temperature at the store sensor reaches 95 °C, all cooling functions
will be blocked. The switch-on hysteresis is -5 K.
Note
If one of the cooling functions or the antifreeze function is activated, the
drainback option will not be available.
System cooling
The system cooling function aims to keep the solar system operational for a longer
time. The function overrides the maximum store temperature to provide thermal
relief of the collector eld and the heat transfer uid on hot days.
If the store temperature is higher than the adjusted maximum store temperature
and the switch-on temperature difference DTO is reached, the solar pump remains
switched on or will be switched on. Solar loading is continued until either the tem-
perature difference falls below the adjusted value DTF or the collector emergency
shutdown temperature is reached.
In 2-store systems the sequence of the stores can be adjusted.
If the system cooling is active, ☼ is displayed (ashing).
Note
This function will only be available if the collector cooling function, the heat
dump function, and the drainback option are not activated.
Store cooling
When the store cooling function is activated, the controller aims to cool down the
store during the night in order to prepare it for solar loading on the following day.
If the adjusted maximum store temperature is exceeded and the collector temper-
ature falls below the store temperature, the system will be reactivated in order to
cool down the store.
DTCO and DTCF are used as the reference temperature differences.
Heat dump
The heat dump function can be used to direct excess heat generated by strong
solar irradiation to an external heat exchanger (e. g. fan coil) in order to keep the
collector temperature within the operating range.
The heat dump function can either use an additional pump or valve (OTPUM
ON = pump logic, OTPUM OFF = valve logic).
DTCO
Switch-on temperature diff.
Adjustment range: 1.0 … 30.0 K
Factory setting: 20.0 K
DTCF
Switch-off temperature diff.
Adjustment range: 0.5 … 29.5 K
Factory setting: 15.0 K
OSTC
Option store cooling
Adjustment range: OFF / ON
Factory setting: OFF
OSYC
Option system cooling
Adjustment range: OFF / ON
Factory setting: OFF
COOL 8
PUSH
8
a
d e f
OHDP
Heat dump option
Selection: OFF / ON
Factory setting: OFF
OK
OFF ON
OHDP
PUSH
BACK
PUSH
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