I have changed my resin today for the first time after purchasing a system from Pure Freedom,the problem is that I am not getting much water and the preasure gauge is not moving at all,the system is fitted with a booster pump but no joy,is this normal after changing resin 
Sounding like a air lock, do you have outside ports ? if you do, turn on system connect hose if water is not coming through, disconnect the hose again while still on you should be back pressure re connect and it should sort it, if not, you may have and air leak on your filters, these are some of the probnlems I have had and I hope they can help you sort it.
Ian