Press the "On" button on the spa remote. The display will show the set temperature unless the spa has been locked. The lock icon will be displayed if the temperature is locked. To unlock the temperature lock, press the "Mode" button in the "Tools" submenu until the lock symbol lights up, then press the "Off" button.
Increase the temperature of the water by pressing the "On" button again. Each time the button is pressed, the set temperature will go up by 1 degree. Hold down the button to increase the temperature a degree every half-second.
Set the temperature lock to hold the new temperature. To activate the lock, locate the "Tools" menu. Press the "Mode" button in the "Tools" menu until the lock symbol is illuminated on the display. Press the "On" button again to activate the lock.