we have had a 36m putz roll and fold and very seldom plug while pumping maybe at the end of the 5 to 3 reducer hose ,we just got a 38m putz z boom and have been pumping in the "z formation" and alot of the time when we shut the pump off for a minute or two the pipe is pluged some where in the middle we back up a couple of strokes and away it goes . is the z pattern causing this ? thanks for the help

Is your 38 a new machine? sounds like the mix is separating..

no 2006 with 700 pump hours concrete is a 5 slump and 1" round rock

Start at the pump end, Check the plates and piston cups for wear and adjustment, She may be bleeding there while you sit and wait, then move down the line, check for build up in the line, gasket gone on a swivel etc.

Interesting that you get 1" rock down a 3 " line- we got no chance of that over here!!

i will look at that . our rock is what we call river rock kinda like oblong marbles pretty easy to pump thanks

sounds a lot like your wear plate , river peble mixes bleed because the peble doesnt absorb water.

It does sound like a wear plate or cut ring issue. I poured a job a while back, same pump, 38z putz, same issue, and we replaced wear parts. It worked well for a while, but I continued to still have plug issues in the third section. I found that it worked better when you cut the pump off, you needed to leave the third section at about a 30 to 45 degree angle instead of a hard 90 angle. That allows for the concrete to not fall back and separate as easily. Hope this helps.

I'd check your cutting ring.  I had the same problem on my 36 putz roll-n-fold.  I couldn't figure it out for about 3 months and finally it was so bad that i couldn't take it.  the ring was worn at the very bottom of the s-tube where you couldn't see it without pulling the tube out.  I found it and replaced it and it's been like a swiss watch ever since.

 When the pump is turned off for more than a minute or two try taking a full stroke in reverse before you start again. If it's bleeding water & fines somewhere it creates a pocket of rock & sand that plugs once it's pumped further up into the system. By reversing the pump one or two strokes it backs the rock pocket back into the hopper so it gets remixed and doesn't plug.

thanks for the advice i will check out wear parts

Murf is on to something that you should listen to 1 inch rock no matter what type it is is wrong for 3 inch  this is the way I was told that you rock size a multiply it by 4 so with 1 X 4 = 4 inch ended hose with what you got it should  be 3/4 X 4 =3 INCH so this is the safe size to pump threw a 3 reducer hose some day that will split and hurt a hoseman.

What about when you pump 2 1/2 stone, threw 4 1/2 pipe? Our normal stone is about 1 inch to 1 1/2 inch, times 4 would be 6 inch hose.

OK I'm now running a 38"Z" and seem to have the same problem.But, I wonder,is it plugging up, or is it the rams going out of sequence? Tickle the toggle below the horn on the remote box,and it clears up instantly.

Yep, sounds like they are out of sequence.

Reverse the pump! even if its a new one!  Its a good habbit to get into!!!     POUR IT OUT

Just remember that the Z- Boom is in a W-Shape formation, while your pumping. So, Your going to have 4-Points of Resistance! And a Roll n Fold is in an A-Shape, while your pumping! So, you only have 2- Points. The size of the rock doesnt help either. The larger the rock, the less fines you have per-yard to slick the pipe! And the redusers, I'm not feeling that! I operator a 63m, and all the pipe is 4.6in. I have a hard time with 1in rock!

Flint wrote: "And a Roll n Fold is in an A-Shape, while your pumping! So, you only have 2- Points."

So, do those 4 elbows magically disappear? 

It may appear to the uneducated eye that the direction of flow does not change,  but 2 - 90 degree elbows = 180 degrees of direction change no matter how they are configured. 

Do you REALLY operate a 63M?  Get your oiler to explain it to you.