how do you change the fittings/connections the program puts in

[mjmpe]

I am working in Mep 2013. How do I go about changing the fittings/connections that automatically go on my pipe. for instance I am working with grooved pipe and the couplings that automatically go on are not the correct ones we use. Also I notice some of the fittings do not take out the correct sizes, how do I adjust that? is it in part manager? that looks alittle confusing to me.