Figure No.15 Smart Fire SF 11. SF15, SF22 and SF41 boiler diagram:
8- Exchanger cleaning system lever; 9- Heating water stub pipe; 10- Exhaust gas breeching with
exhaust temperature sensor and Lambda probe (option); 11- Fumes manifold washout hole; 12-
Wiring penetration.; 13- Drainage stub pipe; 14- Connection of drive system for exchanger
automatic cleaning system (Option); 15- Exhaust fan casing; 16- Safety thermostat reset (under
plastic cover); 17- Power cable gland; 18- Return water stub pipe; 19-Air circulation system
connection;
7. Protective and Control Instrumentation
7.1 Capacitive proximity switch
The top part of fuel supply pipe, next to the gear of valve, is provided with capacitive proximity
switch– Figure No. 16 purposed for detection of excessive fuel accumulated inside dispenser pipe,
what is possible before fuel supply to the burner in case of false ignition detection. Capacitive
proximity switch protects the fuel supply system against permanent stoppage resulted from
jamming by accumulation of excessive fuel.
Capacitive proximity switch is connected do the circuit of boiler door limit switch with serial
connection– according to Figure No. 17. Boiler controller displays “BOILER LEAKAGE” message
and stops fuel supply and exhaust fan operation upon activation by the capacitive proximity switch
analogically to detection with boiler door opening limit switch.
Capacitive limit switch circuit is additionally fitted with sensor interlock switch. Activation of
interlock makes boiler controller to ignore detection of excessive fuel by the capacitive sensor, what
follows during removal of excessive fuel accumulated inside fuel supply system. Sensor interlock
switch is located next to the temperature limit reset button STB – Figure No. 18. By default during
boiler sensor interlock switch shall be in ”0” position!
SMART FIRE BOILER User Manual
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