Spheros thermo 231, Workshop Manual

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3 Functional Description Thermo 230 / 231 / 300 / 301 / 350
302
Switching thresholds for Thermo xxx Raill
230.040 230.056 300.124 xxx.126 300.155 350.190
Version Thermo xxx* 350.056 350.155
„VOSSLOH
“
„VOSSLOH
“
973 13A 90 162 37x 90 210 12B
Scope of delivery
thru 90 162 36A
973 13D 90 162 35A
Heater
Control device
638 59D 679 81C 987 10x 978 04x
Auxiliary heating
Upper operating point 85°C 85°C 85°C 85°C
Lower operating point 75°C 72°C 70°C 70°C
Parking heating
Preheating
Upper operating point 85°C 75°C 60°C 60°C
Lower operating point 70°C 60°C 45°C 45°C
Parking heating (economic
setting)
keeping frost-free
Upper operating point 70°C 57°C 20°C 40°C
Lower operating point 55°C 42°C 5°C 25°C
Gradient evaluation
Yes Yes Yes
Hysteresis adaption
Yes Yes Yes
Low voltage threshold
18,5V
(20 sec.)
* xxx means 230 or 300 or 350
3.1 Switch On
Upon switch on the operating indicator light goes on.
Combustion air fan, fuel pump and circulation pump start
operation. (If fitted and temperature is < 0 °C nozzle block
preheater is also activated).
After approximately 12 seconds (run-up time) the high
voltage igniter spark is available. Approximately 1 second
later the solenoid valve in the fuel pump opens and the
nozzle sprays fuel into the combustion chamber to be
ignited by the igniter spark. A photo control circuit
deactivates the igniter box after flame-up.
3.2 Heating Operation
After reaching operating temperature the control unit
takes over to provide controlled operation by activation
and deactivation of the burner in order to maintain a nearly
constant temperature of the heat exchanger (coolant).
The heating operation is terminated as soon as the upper
operating point is exceeded.
The heater now is in the control idle period. Heater
operation is resumed when the temperature drops below
the lower operating point.