Low-water cut-off system

A fluid-level detecting system for determining if fluid is at a predetermined level within a fluid-containing space in which fluid could be at the predetermined level, the fluid being transmissive of a signal, comprising:

• signal generating circuitry capable of introducing such a signal into the fluid-containing space such that the introduced signal is present for sensing within fluid at the predetermined level if, and only if, the fluid is at least as high as the predetermined level,
• a probe and probe-responsive circuitry capable of sensing the presence of the introduced signal within the fluid at the predetermined level, and
• control circuitry capable of providing a control function in response to whether the introduced signal is so sensed, in order to indicate whether the fluid has a level is at least as high as the predetermined level.

A Method for determining the presence of a fluid at a predetermined level within a fluid-receiving space in which the fluid can rise to the predetermined level, comprising:

• introducing a signal into the fluid-receiving space such that the signal is present for sensing within fluid at the predetermined level,
• sensing for the presence of the signal within the fluid at the predetermined level, and
• providing a control function in response to whether the signal is so sensed, in order to indicate whether the fluid is present at the predetermined level.

The method of electronically determining whether fluid is at a predetermined level within a fluid-receiving space, comprising:

• introducing a signal into the fluid-receiving space such that the signal is present for sensing within fluid at the predetermined level,
• sensing for the presence of the signal within the fluid at the predetermined level, and
• providing a control function in response to whether the signal is so sensed, in order to indicate whether the fluid is or is not present at the predetermined level.