Automatic Speed Control (Sigma); Fan Start/Stop; Ch Pump Operation; Safeguards - Tech Controllers EU-24 SIGMA User Manual

in sustain mode.
Blow-by pause function is activated by pressing OPTIONS button until "przerwa
przedmuchu" LED goes on. Here, the user should set the blow-by pause time (in minutes) in
sustain mode.
The sustain mode (when the CH temperature remains above the preset value) prevents the
boiler fire going out and limits further temperature rise.
ATTENTION: Incorrect setting of both the blow-by operation and pause may lead to constant
increase in temperature! The user should especially ensure that the blow-by pause time is
no too short and the blow-by operation time is not too long.

Automatic speed control (SIGMA)

When the boiler temperature rises, the controller gradually lowers the fan speed until it
reaches the preset minimum speed.
For example, when the minimum speed is set to 2nd gear, the preset temperature is 60°C
and the boiler temperature is 49°C and it is rising, every 1°C the fan slows down and
changes into a lower gear until the temperature of 1°C below the preset value is reached (in
the 2 nd gear) When the temperature is reached, the fan stops and operates according to the
preset blow-by operation and pause cycle.
When the boiler temperature drops below the preset value, the fan gradually speeds up ( it
changes into a higher gear every 1°C) until it reaches the maximum rotational speed.

Fan START/STOP

(function available depending on the software version)
EXIT button is used to enable the fan during the fire-up process. When the function is
activated, both the "fan" and "manual mode" LEDs go on. When the boiler temperature
exceeds 30°C, instead of "manual mode" LED "CH pump" LED goes on and the CH pump is enabled whereas
the controller enters the operation mode.
In operation mode of the controller, the button is used to switch the fan on and off (e.g. when adding fuel).
Then, after the fan is disabled, "manual mode" LED starts to flash. The function ensures safe operation of the
boiler. When the fan is on, the boiler door must not be opened.

CH pump operation

CH pump operation depends on the boiler circulation temperature. When the temperature reaches 30°C, the
pump is activated. When the temperature remains above this value, the pump operates without pausing. The
pump is disabled when the temperature drops below 28°C to prevent unnecessary operation of the pump. When
the pump is operating, a corresponding LED with the pump symbol is on.

Safeguards

In order to ensure safe operation, the controller has been equipped with a range of safeguards. All errors are
shown on LED display:
E4 – boiler temperature has exceeded its maximum value (set to 85°C)
E5 – temperature sensor has been damaged
In both cases the fan is disabled, the CH pump is enabled (if so far it was disabled) and an
alarm sound appears. In the case of E4 error, the alarm may be cancelled with the use of
OPTIONS button when the temperature drops to a safe level. In the case of E5 error, the
sensor must be replaced (after checking that there was no short-circuit and the sensor cable
was plugged in correctly).
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