Rotex Controller Series, Product Documentation

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EbV Product documentation THETA NORM/UNIT
7-5
CAUTION In connection with a room sensor, the thermostat function is not active with active frost
protection.
Cycle Operation
The existing frost protection function will be complemented by the option of cyclic frost
protection in Version 2.1.
The frost protection function is activated as soon as the temperature drops below the set
frost protection limit (
SYSTEM-PARAMETER 5
), in the same way as before. The frost
protection function becomes effective when frost protection is active and there is no
request from the heating circuit.
• With the frost protection setting "Cycle operation", there is no continuous request for
the heat generator, in contrast to continuous operation.
• With active system frost protection, the heating circuit pumps are switched on and
the mixer valves closed.
• As long as the measured flow temperature of the mixed circuits or the heat generator
temperature in the direct heating circuit, respectively, does not drop below the
current set room temperature (RT
Frost
or RT
Night
), no demand value is sent to the
heat generator.
• When the flow temperature drops below the set value, heating is activated.
• Once the set flow temperature has reached the set room temperature and the set
time (
SYSTEM-PARAMETER 19
) has expired, the demand value to the heat
generator is retracted and the mixer valve closes while the pumps continue
operation.
• If no measurements are detected from the outdoor sensor (e.g. because the sensor
is defective), only the pumps are switched on while heating is disabled.
• The set minimum and maximum limits are taken into account in heating operation.
• When the heat generator is activated, the set start-up protection conditions of the
heat generator are applied. This means that the heating circuit pumps may be
switched off temporarily.
Frost protection function in case of heat generator fault
If system error message 30-3 or 31-3 occurs (e.g. switch-on failure of the burner(s) due
to fuel shortage or burner malfunction), priority pump switch-off functions such as boiler
start-up protection, hot-water priority etc. are dis-abled if frost protection is active. The
heating water circulated in the heating circuits adopts the overall mean room
temperature and reduces or delays any freezing.
Operation:
Note on operation Key / parametertree Parameter
System frost protection
SYSTEM PARAMETER 05
Frost protection cycle operation
SYSTEM PARAMETER 19