Dredge Trouble Shooting

So when you are doing the first inspection on the pressure hose, make sure to look for turbulence and quickly moving bubbles. They should go away almost entirely within the first ten to twenty seconds of operation.

By using a clear plastic material so that it is able to get inspected visually, when the high pressure hose is working the right way it should look like it is full of water but should not show that it is moving a tremendous amount. Try squeezing it in between your fingers and when this is done it should give you a lot of resistance and should not fold. If you notice there is a lack of resistance it is most likely sucking up some gases.

In order to resolve this problem you should first check the clamp of the intake hose to ensure that it is on tight enough. If you are not sure, you can put your hand in the water and dribble some water on the area of the clamp. If you see that the water is sucked in, then you know that the problems is that the pump is sucking in air and tightening the clamp should take care of the problem. 

If this is not the problem or does not work, try running your hand over the are of the suction tube above the surface of the water in order to check if it has a leak.

If this still does not seem to be the problem you should check the position of the foot valve and strainer. It could be that the strainer has moved to an area where there is underwater turbulence and cavitation that cannot be seen from the top. If this does happen, it is possible that vaporized water is being sucked into the pump where it will not only slow down the speed of the pump but will also ruin the impellers and covering too. To take care of this problem, just move the strainer to a different more peaceful section of the stream.

If none of the above tests work, you may have a defective pump covering. If this is the case there is a test that can easily be done to prove it. Start out by checking the outside circumference of the pump covering. If there are any cracks or little imperfections you will be able to notice bubbles or little jets of water coming out from the covering. Due to the fact that no air would go into the casing because of this type of defect it is unlikely little leaks here will cause the pressure to drop so it is not probable that a loss of water speed would be noticed here.

The last thing you can do is around the intake inlet junction where it joins the pump casing. Most likely you should see the water being sucked into the pump that would show that it has a defective casing.

Obviously if all of these easy tests show that there is a defect in the pump or suction hose the part that is not functioning should be returned to the manufacturer so it can be replaced.

If all of these tests were to be done and it seem that none of them are the problem, then the best thing would simply be to shut down the dredge and rest for a moment. You can move to another place as well. After waiting for a little while, try starting it up again and very carefully prime the pump and follow the instructions of the manufacturer.

If the amount and speed of the sluice continues to be slow, or if a big amount of air still remains in the high pressure hose, it is logical to suppose that something inside the pump casing is defective. It could be that the impeller casting is not functioning or any number of problems that could cause the impeller to turn unevenly which would then cause turbulence and cavitation. If this were to be the problem, more inspection by the owner of the dredge is not really worth it since the problem is more intricate and it should be returned to the manufacturer with a full explanation of what occurred so that the problem can be resolved.

When there is a really long suction or high pressure hose where the amount of air is considerably above, it is suggested to get rid of as much of the air as you possibly can by filling the air hoses with water before you turn on the engine. This is specifically true of the movable ejector type that usually has a pressure hose that is fifteen feet or more. Finally what can be done if there is difficulty with priming is to fill the whole system with water before turning the engine on. This will only leave a teensy amount of air in the pump to be expelled.