Your pump should run only as required to expel water from the basement. A device that doesn’t turn on, even when the floor floods, clearly needs repairs.
You should also call for service if it runs constantly despite a lack of water. The float switch may need fixing, or the drain line may be clogged.
Finally, the machine may rapidly cycle. This occurs when it turns on and off frequently, no matter the water level. It often signifies loose power connections or problems with overheating.
When condensation forms on walls and floors, the appliance may not function correctly. This occurs even without an inch of water or other signs of flooding. However, a flooding basement provides an incontrovertible sign the device doesn’t work.