(edited by Dabu.1258)
How Works? Remove Condition
It is a skill on your elixir gun and yes, you have to groundcast it unless you have the kit refinement trait, then it autocasts at your feet as well when you swap to the elixir gun from another weap/kit.
Initially the combo field only removes a single condition (Besides the AoE heal) but if you use your #1 skill (elixir gun/pistol/rifle etc) it will remove a condition with each shot for as long as the field is active. It does this for anyone inside the field for its duration.
Hope this explains it somewhat.
i know all about that explanation, but if you can see in this picture the burn is not removed.
You sure it doesn´t get reapplied every tick since you´re standing in the AoE?