Particle System won't play on awake

I am making a platformer game and I have some lava that if you fall into it you die. I am wanting to make a particle system for the lava, but even though my particle system is set to play on awake, it doesn’t show up in the game.
Any help would be nice.
Jack

A bit late, hope this helps much more ppl.
If you are calling the particle System to Play from Update it won´t work, because every frame you are telling it to play and it begins playing every frame. The feeling is that the particle is not playing, but indeed is reseting to particle frame 0 every time in Update.
The solution is not calling particles from update or using a boolean var to check if it´s playing.
Particle system has this.