First of all, if a sensor is not working properly, there is no need to remove it from the configuration. If it needs to be replaced with the same type: you can simply disable it by unchecking the checkbox until it is repaired or replaced. An icon with a blue exclamation mark in the status windows will indicate that the sensor is disabled.
Status window. Note that everything above the sensor is also marked with an exclamation point to indicate that something is disabled.

Also, if you need to move the connection from one ZPU channel to another, the best practice is to cut/paste the sensor. The data will follow the new channel and the result will be transparent.
But if you replace the current sensor with another model, for example a PCS-302 for a PCS-304, it is necessary to delete the existing sensor and configure the new one on the same channel. The sensor will be removed from the current configuration, but the corresponding data will be preserved and available to be displayed if you select a measurement taken before deleting it.
If you export the configuration to be able to create a new database, only the real sensors will be exported, the deleted one will be removed from the configuration to avoid keeping inactive data in the database.