Not to hijack this very useful thread, but could the scent additive have caused the fogger problems? I know that Froggy's states that their scents will not harm foggers, but everything I've read/heard about using fog scents says they're bad for the heat exchangers.By the way, make sure you add a scent to the fog. It makes a HUGE impact. Last year our fogger started acting up, so not much actual fog in the graveyard, but the scent was everywhere. It totally made the whole scene come together.