Spheros Thermo S 160, Руководство по ремонту

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s n o i t c n u f r e t a e H 4 0 0 4 / 0 5 3 / 0 0 3 / 0 3 2 / 0 6 1 S o m r e h T
403
Once the temperature falls short of the lower switching
threshold, the heater restarts burner operation. It runs
through the same sequence as the switching-on
sequence.
Different switching thresholds are defined for different
heater operating modes.
The switching thresholds are selected depending on the
present condition and the selected heating operation.
The following switching thresholds may be applied.
t
Parking heating mode an d auxiliary heating mode
t
Gradient evaluation
t
Minimum combustion period (also called hysteresis
adaptation)
t Saving mode 1 and saving mode 2
The switching thresholds can be obtained from Table 401.
4.2.2.1 Auxiliary heating mode and parking
heating mode
The control unit received the information, whether the
vehicle engine is running or not, from terminal D+/+61.
If terminal D+/+61 is connecte d and the vehicle engine is
running, the switching thresholds in auxiliary heating
mode are higher than in parking heating mode with the
engine not running.
In that case a saving mode is activated in parking heating
operation.
If terminal D+/+61 is not co nnected, then there is no
distinction. The heater always runs in parking heating
operation.
4.2.2.2 Economy modes
Two different saving modes are programmed in the
control unit.
Saving mode 1 and saving mode 2 exist (see table 401).
In saving mode 1 the switching thresholds are higher than
in saving mode 2.
If saving mode is activated, the controlled temperatures in
the heating system are maintained at a low temperature
level. The lower and upper switching threshold are
reduced.
Due to lower radiation loss the fuel consumption can be
reduced for a lower heat demand (e.g. warmer mode).
The heater burner output is not reduced.
In auxiliary heating mode (sig nal from terminal D+/+61)
saving mode is automatica lly deactivated (see 4.1).
4.2.2.3 Gradient evaluation
In case of low coolant flow or poor coolant circuit venting
the temperature quickly increases in heating operation.
The control unit recognises the quick temperature
increase and automatically sets the upper switching
threshold to a lower value.
The quicker the temperature increases, the lower the
switching threshold for starting the controlled break is set.
In addition, the burner is also switched back on again after
the controlled break at a lower switching threshold.
This prevents residual heat triggering the overheating
protection.
4.2.2.4 Minimum combustion period
A minimum burner combustion period of 120 second is
targeted.
For ambient and operating conditions this target is not
always achieved.
In order to achieve the minimum combustion period, the
lower switching threshold is variably adjusted by the
control unit.
This process is also called hysteresis adaptation and is
applied in parking heating oper ation as well as auxiliary
heating operation.
If the combustion period falls short of the minimum
combustion period, the lower switching value is lowered
by 1K for the following combustion process.
The upper switching threshold remains as is.
This can be repeated until the minimum combustion
period is reached or the lower switching threshold is
reduced by 5K.
Further lowering is not possible.
Following a combustion process, where the required
minimum combustion period was reached, the lower
switching value is reset to its original value.
4.2.3 Switching off
Switching the heater off ends the combustion process.
The operating display expire s and run-down is initiated.
The solenoid valve closes, the flame expires, the
combustion air fan and circul ating pump continue running.
The run-down ends approx. after 120 seconds. The
combustion air fan is switched off.