ITC 1000 Powering on and off

The ITC1000 powers on when power is applied to it. Is it possible to have it only power on using the on off button on the face. I am using it for heating on a sailboat. It’s wired to the cabin light circuit. When I activate the switch the thermostat powers on turning on my fan heater.

Sorry, the ITC-1000 turns the output on/off based on temperature readings and settings, it cannot turn the output on/off manually.