Otherwise, the boiler would overheat and this would cause damage to the controller. When this protective
equipment is activated and the temperature drops down to the safe level, the sensor automatically turns off. In
case the sensor is damaged or overheated, the ventilator is also disconnected.
In case the CH boiler protective equipment is of a closed system type, the STB type temperature limiter is
used instead of bimetal mini sensor.
VI. C) Automatic sensor control
In case of damage to one of the temperature sensors (CH, DHW or fuel tank), the alarm signal is activated and
the monitor informs about the failure, e.g.: “
CH sensor damaged
”. Both the feeder and the fan are deactivated.
The pump functions despite the current temperature.
If CH sensor or feeder sensor are damaged, the alarm is activated until the installation of a new sensor. If DHW
sensor is damaged, the alarm must be deactivated by pressing the “
MENU”
button – the controller restores the
operation with a single pump (CH). The new sensor has to be installed in order to use all the CH boiler operation
modes.
VII.d)
CH boiler protection from the boiling water
This protection is applied only for the water boiler priority mode when the water tank is not sufficiently heated.
When the set water boiler temperature is 55
O
C, whereas the actual CH boiler temperature reaches 62
O
C (also
called the priority temperature), the controller disconnects the fan feeder. If the CH boiler temperature is
increasing and reaches 80
O
C, the CH pump is switched on. If the temperature increases further, the alarm is
activated under the 85
O
C temperature. It usually happens when the water boiler or the pump are damaged or in
case of improper installation of the sensor. When the temperature drops down at 60
O
C, the controller turns on the
fan and the feeder and operates on the set mode until the temperature of 62
O
C is reached.
VII.e)
Temperature protection
The controller is characterised by additional protection against hazardously increasing temperature. If the alarm
temperature exceeds 83
o
C, the fan is deactivated and the pumps are activated to distribute hot water throughout
the entire equipment. When the temperature exceeds 85
O
C, the alarm is activated and the monitor shows the
following alarm message:
“
Temperature too high”
VII.f)
Thermal CH boiler protection (STB)
STB safety thermostat is installed in a closed CH system controller which protects the CH boiler from extensive
increase in the temperature. In case the pre-set “disconnection” value is exceeded (default value: 95
o
C), the
feeding circuit contacts of the fan are opened. The fan can be reactivated only manually after pressing the safety
thermostat “reset” button for the sensor to cool down.
VII. h) Fuse
The fuse WT 6.3A that protects the network is installed in the controller.
It is not possible to use a higher capacity fuse as this may lead to the damage of the controller.
VII.
Maintenance and technical data
Before and during the heating season, it is necessary to check the technical condition of
ST-560
controller
cables. The user also has to check if the controller is well installed and it must be clean. It is recommended to
measure the earthing parameters of engines (CH pump, DHW pump, fan and feeder).
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