For 18" models:
The flame and heat functions work on separate switches, located on the fireplace insert. You can turn these on or off independently or together.
For all other units:
The flame and heat functions work separately, but when the features overlap, it can be a bit confusing. The control panel stays illuminated for only a few seconds after selections are made, so the first step is to ensure that the lights are on. Pressing any of the gray buttons on the remote when the unit is on will do the trick.
Next, if your heat and flame functions are both on and you want to enjoy the flame only, you would need to press the button on your remote with the three wavy lines. This button turns the heat on and off, but it does take a 5-10 seconds to power down. The blower is rotating quickly, and it takes this long to slow to a stop. You can press this button again to turn the heat back on, but remember that the control panel must be awake and to wait several seconds between clicks.