what do I call this relay?
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Control circuit.

Your question is a little confused but I think this meets your requirements.


XFMR1 is the mains to 24 V AC transformer.
RLY1 provides power through its NC (normally closed) contact to the rest of the circuit. When the float switch contact closes RLY1 is energised and power to RLY2 is cut.
RLY2 runs the pump when it is energised.
Pressing START will cause RLY2 to be energised and run the pump. A second NO (normally open) contact bridges out the start button and keeps RLY2 energised until STOP is pressed or the float switch contacts close or the power fails.


The relays are called 24 V AC control relay. Make sure the contacts are rated for voltage and current at least as great as your load.

If this isn't quite what your require then please edit your question to clarify and post a comment below to notify me.