The level limiter electrode E4B is, in combination with the switching amplifier B3 (see Operating Instructions H001), a level limiting devices of a "special design type". The combination of equipment recognises the minimum permitted water level LW (= low water) in steam and hot water generators.
The function of the level limiter device is based on the different conductivity of water and steam. When the level limiter electrode is immersed and removed, a bridge switching in the switching amplifier B3 is unbalanced. This signal is amplified and switches the output relay of the switching amplifier, which, with its contacts in the safety chain of the firing, triggers a fault shutdown.
The LW switching point is permanently set through the place of installation, location of the level limiter electrode and electrode rod length and can only be changed as described in Chapter 9 "Assembly".
If the level falls below the LW switching point or if the permitted monitoring current of the insulation monitoring is exceeded, then the light-emitting diode (LED) on the switching amplifier goes off, the relay in the switching amplifier returns to the starting position, and the firing is shut down due to a fault.
With steam generators, the level limiter electrode is installed in a protective pipe to avoid any dangerous incorrect operations as a result of foam formation in the boiler water (foam simulating water).
With hot water generators, it is usually installed in the supply flow adapter piece without any other protection.
The function of the level limiter device is based on the different conductivity of water and steam. When the level limiter electrode is immersed and removed, a bridge switching in the switching amplifier B3 is unbalanced. This signal is amplified and switches the output relay of the switching amplifier, which, with its contacts in the safety chain of the firing, triggers a fault shutdown.
The LW switching point is permanently set through the place of installation, location of the level limiter electrode and electrode rod length and can only be changed as described in Chapter 9 "Assembly".
If the level falls below the LW switching point or if the permitted monitoring current of the insulation monitoring is exceeded, then the light-emitting diode (LED) on the switching amplifier goes off, the relay in the switching amplifier returns to the starting position, and the firing is shut down due to a fault.
With steam generators, the level limiter electrode is installed in a protective pipe to avoid any dangerous incorrect operations as a result of foam formation in the boiler water (foam simulating water).
With hot water generators, it is usually installed in the supply flow adapter piece without any other protection.
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