Source Green Heat SGH-1500 - Manual (Page 14)

14
5. Setting Electro Lock
The Electro Lock can help avoid the heater from being accidentally engaged by children. The locking
mechanism can be set in both the ON and OFF modes.
And
Press Temp Up and Temp Down buttons at the same time
for 3 seconds. Locking is complete when you hear a beep.
When locked, the functions of the control panel and remote
will be locked for use.
And
When you need to unlock it, press Temp Up and Temp
Down buttons at the same time for 3 seconds. You will hear
a beep. The control panel and remote control will become
functional again.