Conductivity electrode level switch

An electrode is placed in the steam dome and the length of the electrode decides the level where the alarm shall occur. A low voltage alternating current passes through the water in the boiler to the electrode and the circuit breaks when the water level falls below the end of electrode. This method is mainly used for high and low level alarms. It is also used, in small size boilers, to start and stop the feed water pumps. Deposit on the electrode is not a problem. Normal degree of coverage does not disturb the measuring results. The measuring result is sensitive to dense foam in the boiler.
It’s normally one electrode for emergency low water level alarm, or two electrodes if also high level alarm is required. This water level sensing method is also common on small boilers for start and stop of the feed water pumps. Up to six electrodes can be used in one electrode stand.