We had a breakdown last week on our 38M boom pump, and our operator finally had to clean the boom line using a cap on the tip end and compressed air to push a ball thru the system to clean it.  After fixing the pump, we have used the truck twice and had prime problems both times.  I am thinking the system is not clean.  Any idea's on how to clean the system?

You can pump really hot or cold water thru the boom and tap on the pipe to break it up.

Obviously, this would have to be done well before or after a job....or blame the readymix for plugging.

:)

So this brings up the question of who is responsible for the 'lost' concrete on the job because the pump job was not completed? Any ideas or experience with this?

check the boom pipe for leaks, anywhere the cement is squeezed out of the mix ,the rocks will jam, use a go-devil hard rubber plug to clean out with, it is 5 1/2 inches diamenter, pipe is 5 inch so it scrapes it clean

http://www.conforms.com/products/accessories/cleanout.html

try this just be careful..blow from the tip to the hopper all clamps tight if the plug get's stuck you will haved to kill the air tap the line till you find the godevil and remove the blockage..good luck

I would take off all the corners and clean them with a hammer and chisel from the inside out. if the corners are off you can check the boomlines if they are open but mostly the cocrete stays in the corners. I strongley disadvice the methode given by previous speaker to hit the lines with a hammer from the outside because most boomlines are twinpipes meaning they are two layers of different kinds of steel ( a normal 8.8 steel for the outside and a hardened steel for the inside) wich means that the outside steel is bending but the inside steel is breaking. that way you can sevearely damage the lines. second reason is that if there is some hardened concrete in the line and you should be able to loosen it from the lines, the hardened piece of cocrete will be stil in there and will cause blockages while pumping and create dangerous situations for both operator and cocrete placing crews as well as bystanders and houses in the area. to prevent this problem one should not wait an hour to empty and clean the lines if you are in trouble with the pumping mechanism. if one is not able to mend the problem withing 15 minutes one should allready start to empty on water and air using the blowouttube (the one with the two taps on the same page as previous speaker) and two balls. you put one ball in the tip of the boom and the second one in the back of the tube and connect it to the tip of the boom, you open the tap closest to the tip and pump water in it (about 200 liters will do) then you close this tap, then you connect your airsupley to the other tap and blow it out. this way you can be sure the lines are clean enough to put the machine in repair for a few days. if you wait with this procedure like an hour, the mud has already taken possition in the lines by the cotinuous vibrating of the motor of the vehicle and can not be washed anymore. hope this has helped a bit

elbows tend to collect much of the paste.Pull elbows and inspect,they can take a little banging.Also check the turret and deck pipe/reducer (6-5).Nice thing when elbows are off you can look down pipe and see.

Hot water on a cold boom is great,ask they fin fish,works every time.

Try to send the 38 out to a big job with lots of m3 and pump hard (thats HARD)  300/500 m3 should do the job... ;-)

The bad thing about trying to pump the buildup out on the job,who eats the booboo if one plugs?

Many, that's kind of what I was getting at. Also, if you have an issue that in known with the pump, why would you attempt a paying job to remedy it. If that is the preferred route - to 'pump it clean', spring for a yard and a half yourself and recirculate it at high speed in your own yard for 2 hours.

What was the cause for the breakdown ? And if it "only" took compressed-air and a ball to clean the boom I dont think there is some mud left in the boom . Why didn't you pressed some hard sponges with water after you had "saved" the boom ? I think it is a "brainghost" after the breakdown and the operator not doing the samething he use to do normal when priming... How long has he or she operate a pump ?

Before I were to take all the elbows off, I would find out how many strokes it takes before it plugs. This will give you a good idea where to start looking. If you get plugged within the first 3 strokes then it is the deck or turret. If it is after 3 strokes, do the math and narrow it down.

In cases such as this I never took the lazy way,I wanted to know.It really isn't that much work,besides the swivel gaskets probably needed changed anyway.

your problem began when you blew a ball back with air, in my experiences its better to take the 90s off and check all for build up including straight pipes years ago I made the mistake of blowing a ball back instead of a godevil and needless to say I was locking up the whole next day with chunks of buildup breaking loose a good day to run a reducer (keeps the plug in steel) plus it creates a little back pressure to help break the build up out, just be careful.perfect scenario is take apart at yard and clean them out.

Many....I did not mean it as to find the easy way out. It is one way to narrow it down while on the job if you did not previously have time to take 90s off. Plus it is good info for the newer operators to maybe learn to count strokes as they prime incase it were to plug, they know where to start.

Just a thought...anytime we have consistently had poor primes on our putz booms and trailer pump, the problem has been that we're losing the cement content back into hopper to to worn out cutting ring/wear plate. Replacing those works every time, just takes us a few bad days to remember to look for that! If its a Schwing pump, your kidney seal may be bad. Other possibilites may be worn out rear seal kit. I'm not familiar with other brands so others may know more. It is very possible to have shiny clean pipes and trouble priming. Hope you get er goin!

First story. The same thing as sucking a soft ball back.

Break your elbow, if the sponge bypassed concrete it is in the elbows, just break them and look, next time you blow a boom blow the first sponge or ball then fill the tip elbows with water ( about 5 gallons ) then blow a second ball slowly.

I was pumping for myself, so that was not an issue.

I am lucky in this way, I have a large mixer fleet behind us, prime small rock, then move to next job or use rough mix to wear it through, but pending on how bad it is of course. Pulling sponges, well slow and steady but two if its been a hot mix, and small rock with calcium can leave build up in elbows and of course in house. Small rock and hot conc, get the dble sponge and sugar.