Strange WW 1.0 CAT Pump Pumping Problem?

[Carl]

I have a WW 1.0 and its CAT pump is running very odd lately, not pumping steadily when just the boom nozzles are washing and the side nozzles are closed.

The pump is fine, pumping w/ steady psi whenever all seven of the oscillator boom bar nozzles are opened up (three bar's nozzles at the boom, two bar's nozzles along each gantry's side) but whenever the boom goes to drop down to wash either at the front or at the rear of the vehicle, and only its three oscillator boom bar nozzles are opened up and washing, YOU CAN HEAR A NOTICEABLE FLUCTUATING AND "STRAINING SOUND" OF THE CAT PUMP but then as soon as the boom is back up and the other side four oscillator boom bars' nozzles all open back up, the pumping psi is again steady instead of FLUCTUATING AND MAKING A "STRAINING SOUND" when only the three oscillator boom bar nozzles of the boom are the only ones open?

Any idea what might be going on here? Do you think I need to change out the regulator or should I try pinpointing something else as this problem's culprit?

Thanks in advance for any ideas you might be able to share w/ me! - Carl

 

[robtl]

How does the pump sound when the undercarriage is running? when it is running the pump is on med. pressure. not sure about just when the top boom is on if it is in med pressure or not???? you can check to make sure the med pressure solenoid is working,,,,I also believe when the rocker panel pass is on it is on med pressure also,, just my first thoughts.
Bob

 

[Buzzie8]

I had the same problem when I first installed my reclaim system. Before the system was installed, to relieve pressure when the side nozzles were not on water was redirected from the unloader back through the pump. We took the bypass and plumbed it back into the reclaim tanks to reduce this odd noise. I am guessing this did not start happening after a reclaim system install but I would look at the hose that is redirected back into your pump. You could remove it and point it somewhere (we connected a piece of 2" PVC and shot it out the door) and see if this reduces the odd noise. Maybe this line is obstructed or the unloader is not functioning properly.

 

[Reds]

I had a similiar problem once because I had inadvertently set the pressure too high. I have also had issues with pressure fluctuating or not getting high enough due to a bad unloader. The unloader is relatively easy to rebuild, but hard to get at the side of the valve that holds the valve seat (on a WW2.0). But it sounds like your problem is specifically linked to the boom function. Is it possible that your pressure is set too high and it is functioning ok when there are more nozzles open to dissipate the pressure but straining when only the boom nozzles are open?

 

[robtl]

On one wizard we had the unloader discharge hose replaced with a cheap hydraulic hose and over time the hose inner liner that the unloader discharged the high pressure loosened the inside and it ended up in the pump head and blocked valves and we almost lost a pump before we caught the problem. check the inside of the hose!

 

[Carl]

Thanks for the feedback! Will let u know what happens...

Bob, Buzzie8, & Reds - Thanks so much for your input!

The medium pressure solenoid seems to be okay. I think you guys are right in suggesting I look at the bypass hose and the unloader. I recently had to install a new unloader so maybe it was a bad one? Or maybe my bypass hose is indeed the problem because I think the last one I put on there was a bit shorter than I would have liked it to be so maybe that has something to do w/ it or like you said, maybe that hose is deteriorated? Will check these out and let you guys know which one was the culprit indeed. Thanks again!

 

[Carl]

And the Repair Fix Turned Out to Be...

...a bad unloader!

Wanted to again thank you guys for giving me ideas of where to begin to look to fix this problem. Replaced the unloader today and it got rid of the "choking CAT pump" problem. What I'm kind of embarrassed about, and the only excuse I'll give up front is that my brain right now is all-over-the-place to where I'm worrying about too many other things right now to focus, is...

I'd JUST put a new unloader on this automatic back on 3/22/11. If I'd simply put 2 + 2 together and realized that this problem started sometime around the same time A NEW UNLOADER WAS INSTALLED, I could have more quickly and easily figured this one out but...

Another excuse of mine is that when I put the 3/22/11 unloader on, it was TO REPLACE AN OLD ONE so I assumed the new one was good.

Lesson learned: Never trust even a supposedly "new" part 'cause even if it's new, it could be a "lemon".

Thanks again! - Carl

 

[robtl]

Glad you found the problem, was the bad unloader new or rebuilt? we keep one rebuilt at all times to have one ready to replace, the only problem we have with rebuilding them is you have to buy the factory o-rings to keep them from leaking around the spring. you cannot find the right 0-rings in regular stores.

 

[Carl]

Learning Every Day!

Bob - I've never tried rebuilding an unloader. I might as well learn and take the old one apart, huh?!! Saving money rebuilding parts like this is like MAKING money and that's a great thing especially in this dragging/lagging economy!

Thanks again! - Carl