Any pump experts out there?

[jbarker855]

I have a Crane-Deming 4011 pump that pumps water from a nearby creek into a pond I have. We use it to help keep the ponds from becoming stagnant and to get some flow over a waterfall going from one pond to a lower pond. I am pretty sure the pump needs a little servicing and adjustment, but I have never worked on one of these before. It pumps around 10,000 gallons/hr. 3" suction, 2" discharge. Powered off a 220v Leeson 5hp electric motor.
The problem I am having is that the amount of water this thing pumps is decreasing. I can tell how much it is pumping by how far out of the discharge hose it sprays. Normally it blows the water out about 6 feet. It will do this on startup, but after running a while (maybe 20-60 min?), it will only shoot water out a foot or so.
There is no obstruction to outflow. There is no blockage on the inflow side and it does not suck any air. Does not make any funny noises to suggest a bad bearing. For what it's worth, I have noticed over the past few years that it has become increasingly difficult to get this pump primed at the beginning of the season.
My best guess is that I need to adjust the impeller. It is adjustable axially, so that it can be moved closer to or farther from the pump face to adjust water output. I am not afraid to tear into anything, but I could get in a mess real quick with this though because many bolts on it are so rusty. I don't want to be screwing around drilling broken bolts and putting in heli-coils only to later discover that I didn't have to remove THAT particular bolt anyways. Before I start messing with this thing, I thought I would consult the experts. Thanks for any help.
-Jay

 

[user.69169]

I sure ain't no pump expert unless carrying them and dragging em and bustin knuckles on pumps in the dark makes you an expert. Went and hunted that pump of yours up on Google, and she sure looks like a pretty basic rotary pump. If I can do this link thing right it'll take you to a picture thing that shows all the innards, and who to call for parts.
http://www.dultmeier.com/pdfs/pw4021.pdf

If I was you before I did any disconnecting I'd look at the packing box on that there pump and ease up on the packing. Course before you go to easing you want to squirt some penetrating oil like Marvel Mystery oil on the bolts, and you dang well only want to go to bringing the gland thing up just a tiny bit at a time and with the pump running and wet. Ya DANG WELL DON'T tighten either bolt more than 1/4 turn without bringing the opposite bolt up the same amount unless you want to saw the dang shaft off!!!

I'd bet on the gland cause you say she's been giving you trouble priming for a while.

 

[Mousefield]

I do the same thing, pump water from our creek into a pond in the backyard as well outside watering. I just use a ｾ hp jet pump as this provides me with enough water and pressure. About every 3-4 years I replace the pumps as they stop working, cost about $300.00 to replace and don稚 think they are worth fixing. The water is fairly dirty water and has a brown color to it, has a lot of fine sand which I think helps to wear it out. You are pumping much more water with yours. Is the manufacturer of your pump still in business? Can you get a kit, bearings or gaskets if needed? Sounds like it has pumped a lot for a number of years, could it be worth looking at just replacing it?
Or the best bet may be if it is pumping now let it run till the fall rains and then pull it apart, that would give you the winter to repair it or replace if needed.

 

[Sandlot]

That looks like an open face impeller type pump. If the output is changing after it has run awhile it is normally a suction problem possibly compounded by a warn impeller. Could your suction hose be collapsing or filling with debris? Or, is the creek level changing in the area where the suction hose is setting? If the impeller is getting worn, just a little change in pumping head can lead to capacity problems.

 

[Egon]

Have you ever applied grease to #243 in the parts diagram?

As per (removed) on adjusting the packing gland bolts! Go easy. If'n you get them to tight expect some smoke.

You might want to consider changing out the packing.:thumbsup::thumbsup:

 

[Kays Supply]

To adjust the impeller , you need to be able to get to items 204 and 229. If you pull the motor off and loosen 204 and 229 you should be able to tap the shaft forward to lessen the gap on the impeller. The packing will only leak while under pressure. With an open dicharge, it would tend to suck air more than show a leak. Impeller wear would be slight if pumping clean clear water. Most of the wear I've seen was on trash pumps or deep well pumps with sand in the water.

 

[jbarker855]

Gentlemen, thanks for all the input so far. To answer some of your questions, I believe the manufacturer still is in business and I am pretty sure I can get parts if needed. I don't want to junk this pump, as it is built like a tank. By looking at it, you can tell this is something that is built "the old way". It's built to be repaired if needed.
The suction hose is rigid and is not collapsing. Suction end is always underwater, even when creek level drops. Yes Egon, I have greased it .
Could someone explain why a bad packing could cause this problem? I simply don't understand. My simple understanding is that the packing is just a way to seal water from leaking around the shaft.
If this means anything, the packing drips briskly and steadily with pump off, and slows to almost a stop with pump running. Do packings get too tight or too loose with age? I should also mention that although I usually pump clean, clear water, I did pump a lot of sand inadvertently about a month ago. The suction end got half buried in a small sandbar after a storm, and I flipped the pump on without realizing this. I noticed what happened when I saw brown water coming out of the discharge. Thanks again.

 

[Egon]

Could someone explain why a bad packing could cause this problem?

I'd bet on the gland cause you say she's been giving you trouble priming for a while.

The pump sucks air through the gland breaking the vacuum required to lift the water to the pump. Air locked pump. This leaking air will also lower the NPSH meaning lower pump flow rates.

 

[Mousefield]

[QUOTE Do packings get too tight or too loose with age? .[/QUOTE]

Yes, usually they start leaking. I used to use a graphite impregnated string to repack steam valves. Not sure what they have out there now for packing material for a water pump. Going back a just a few years now but if I remember right we used to have a rotary pump that would feed water to the steam boiler, think I used graphite impregnated string as well to pack that if is started to leak.

 

[RalphVa]

I worked with pumps during my 31 years as chemical engineer and have had a swimming pool for almost 30 years. That leaking packing sounds like your culprit because you say it leaks when shut down and almost stops when running. That clues you that it is actually sucking at the packing. This can be air on startup, and it is probably sucking air now while running.

On our swimming pool pump here, I had to take it apart and remove some vegetation that got sucked into the impeller on it. Its impeller has like a screw assembly on its suction side. This wasn't visible from the outside. I just figured that is what it was from its low head symptoms. Fortunately on it, the entire impeller casing splits.

Had to replace it completely about 3 years ago, along with the filter because both the pump seal and filter assembly developed leaks. Found out in my research that the pump we have here is TWICE as efficient as the pump that our pump company was selling. I proven this by measuring its efficiency; yep, about 60-70% vs. about 33% for the other pump from its literature. e.g. HALF the electricity needed by the type of pump we bought. The one we have is a MUCH bigger diameter pump than typical. I know from chem eng experience that small diameter pumps typically have those low, 33%, efficiencies. In refineries, we're generally putting heat energy into what the pump is pumping; so, a little bit of temperature increase due to low efficiency is no big deal and not an energy hog thing. In swimming pools or plain water pumps, it is. It's YOUR energy bill you're paying.

My wife is pretty handy in replacing pumps. Had to talk her through how to do it once with me in Texas and her in NJ.

Ralph