I'm a relative newbie to the world of refrigeration so a little unsure where to look for some info. I'm trying to find out about ammonia, but the more people I talk to the more questions I seem to have!

What I'm looking for is information about the effects that contaminants in the refrigeration circuit have on ammonia systems. For CFC/HCFC/HFC systems there is info in the ASHRAE handbook about this e.g. moisture levels, but I'm having more than a little trouble finding similar information for ammonia. I know ammonia systems are a lot more tolerant than fluorocarbons but there must be some info out there somewhere - ?