New system put together, original 3/8 fitting in bottom of pot,dropping grit into 3/8 ball valve, into 3/8 T connected to 3/8 bore of pinch valve sleeve. New 3/8 regulators and 3/8 piping on wall board. Air is supplied to pot with 3/8 hose, compressor to wallboard has 3/8 hose. Yesterday system working fine more or less as should. Today started having problems, eventually found the 3/8 hose on end of pinch valve, carrying grit to cabinet was completely blocked up, as was the hose in cabinet. We disconnected both hoses and unblocked, cleared them. completely. Not tried system again. What we are wondering is?, If the pinch valve itself is working as it should and all things being..... equal???. The pinch valve housing, we have put a 3/4 npt x 3/8 bsp adapter on it, to fit the 3/8 hose. What about if we get a 3/4 npt x 1/2 bsp and a 1/2 bore hose. Replacing the 3/8 hose that got clogged up with a larger bore hose to and inside the cabinet, would this prevent the hoses clogging up? Can also get a 3/4 npt x 3/4 bsp adapter so could fit a 3/4 bore hose if bigger would reduce liklyhood of clogging. That said what kind of adapter do I need to fit a 10 mm od tungstun tip into a larger bore hose? I had though moisture but grit feels. spinkles through fingers fine, unless I have this wrong and only requires...... tiny amount of damp in grit to cause clogging problems? The ball valve at start only opened about 1/4-1/3 to start but bit more as time went by. Cheers.