THE OPERATING INSTRUCTIONS STATE “IN MANUAL MODE, THE TRANSMITTER WILL NOT TURN OFF THE APPLIANCE EVEN IF THE ROOM TEMPERATURE IS ABOVE THE TARGET TEMPERATURE.” WHAT DOES THIS MEAN?

It means the transmitter is in manual mode and there is no target temperature set, since the transmitter isn’t in auto or auto-p mode. You can still turn off the appliance by sending an off or off/lo signal from the transmitter by pressing the appropriate button.