The heater may go into stand by mode or appear as it has turned off for a few reasons:
1. If the “ECO plus” function is active, the appliance may switch automatically to a lower heating power than the one displayed for a more efficient energy consumption. It is normal for this to occur a few times per hour while the unit is on.
2. If the desired set temperature has been reached and the thermostat maintains the heat by cycling the unit on and off.
3.The timer was active and the unit has reached the set time.
4. The unit to prevent to overheat shut off, if this is the reason make sure it is not covered and free of object for a 3 ft (1 meter) radius; unplug and wait 10 minutes before plug in back.