Splitter Hydraulic Question

[NCMau]

10 years ago I built a log splitter mostly with parts I had on hand. It uses 11 gpm pump, 5 gal reservoir, 5 in. cylinder and 5 HP electric industrial motor. It worked great until now.Today, however, is having hard time splitting a 12 in log. Before I was able to split logs twice that big.
First thing I did is change the fluid, which it was due anyway, but the problem was not solved. So It has to be either the valve, the pump or the cylinder. There are no significant leaks.
I need a practical suggestion on how to isolate the faulty component(s).
BTW there is a gauge installed at the input of the valve which gives a reading of 500 psi when the cylinder can not go any further. Shouldn't that be close to 2000 psi at that point?
A suggestion would be very welcome.

Maury

 

[J_J]

The relief pressure should be up around 2500 to 3000 psi. That pump should be a two stage pump, and splits starting out at 650 psi, and if it runs into something hard, shifts to slow mode and high pressure.

 

[kennyd]

10 years ago I built a log splitter mostly with parts I had on hand. It uses 11 gpm pump, 5 gal reservoir, 5 in. cylinder and 5 HP electric industrial motor. It worked great until now.Today, however, is having hard time splitting a 12 in log. Before I was able to split logs twice that big.
First thing I did is change the fluid, which it was due anyway, but the problem was not solved. So It has to be either the valve, the pump or the cylinder. There are no significant leaks.
I need a practical suggestion on how to isolate the faulty component(s).
BTW there is a gauge installed at the input of the valve which gives a reading of 500 psi when the cylinder can not go any further. Shouldn't that be close to 2000 psi at that point?
A suggestion would be very welcome.

Maury

I doubt it is the cylinder. Most likely it is the PRV (pressure relief valve) in the valve, or the pump. If the PRV is adjustable you can try that since you have the gauge to set it-you may also want take it apart to ensure there is no debris in it...

 

[Wayne County Hose]

Down on the pump, there should be a plug or something that looks like a bolt sticking out the side of it. Remove it, then turn the screw in a couple turns. Now see what your gauge reads. If the max pressure goes up, it's your pump that's bad. On these pumps, that is the usual failure. If there is no change, it's your valve. From your symptoms, my bet is the pump.

 

[NCMau]

I did turn the screw on the pump and the pressure went up from 500 to 700 psi. Also the motor stalled. (as I stated, this is a full 5 HP, 30A industrial motor that doesn't stall easily).
Is this test a pretty sure indication that the pump is ready for retirement? Any other things I can do before I buy another pump?
Thanks for the suggestions.

 

[J_J]

If that pump is a two stage, and the shuttle type valve that shifts the pressure to 2500 is stuck or jammed, then you will not see the 2500 psi in the low speed/high pressure. The pump starts out at zero and increases up to 650 psi with a light load. Is you electrical motor 3600 or 1750 rpm.

So what you may be experiencing, is a malfunction pump, and you may be able to take it apart and inspect/clean it up, and replace parts as necessary.

I believe the unloader psi is adjustable between 400 to 900 psi.

 

[Wayne County Hose]

Replace the pump. Not worth messing around with it. Does your unit have a return filter? If not, good time to install one. If it does, change the fluid and filter. Crap from the pump is now in your oil throughout the entire system.

 

[NCMau]

Thanks everybody! I'll go with a new pump. This time will upgrade to a 16 gpm.

 

[J_J]

A 16 gpm pump needs about 8 HP for gas engine, but an electric motor has better effenciency, and the 5 HP might run it.

 

[George G]

If the check valve is stuck open. When the unloading valve opens at it's set pressure, the whole system would unload to that set pressure.

If it were me, I would pull the check valve out and check/clean first.