The triple warmer is a fire element (agni) meridian. Fire energy goes up, against gravity. The fire tattva is concerned with moving from the material realm to the spiritual realm through purification (alchemy through fire). But guidance is needed to succeed, which is why we need a guru. The triple burner also controls appetite, thirst and body temperature and coordinates digestion, communicating with the Spleen and Stomach.
The triple burner also rules body liquids to keep them moving. It aids in transforming body fluids and it balances the Prana or Qi between the upper, middle and lower areas. Most importantly, the triple burner delivers Original Qi to all organs.