New 16 gpm pump issues on a wood splitter

[Mntn Man]

It’s the pump for sure. Mine is 11 gpm and I was hitting 3000 before running out of rope.

 

[kevin j]

Not entirely true. A pump produces flow and discharge head (psi). At any given flow there is a discharge pressure. They are inversely related so if flow goes down pressure goes up etc. Those two parameters are a direct function of the system resistance. Resistance goes up, flow goes down, pressure goes up. With the pump discharge blocked (highest system resistance) you will reach the maximum discharge pressure.

You don't really ever want to run the pump there, especially if it's a positive displacement as it will ruin the pump. Testing it like how was advised is fine though.

this is true of a centrifugal pump, but not for a positive displacement pump. Centrifugal, like a water pump, does have a flow versus head pressure curve. Positive displacement moves a constant amount of flow for any given revolution and the pressure is a result of the load resistance that the fliw is being forced through or against.

 

[kevin j]

800 psi sounds suspiciously close to the typical unloading setting for a two stage pump. I suspect that the small section is not being driven and when it reaches 800 psi the large section is unloading back onto the inlet of itself like it supposed to. Or the check valve that supposed to isolate the two might not be in place.
another clue is that you said you have about 800 psi and when you speed up the engine it stays at 800. That tells me it's probably not a leak because the leak the pressure drop across the leak should rise as the flow increases with engine speed. The fact that it stays roughly constant tells me there's some kind of a controlling device in there sensing pressure and doing something to try to hold that pressure.

either way, I would take it back to the vendor. If it was an existing machine in service I would tear into the pump.

 

[ChoppyChoppy]

Not entirely true. A pump produces flow and discharge head (psi). At any given flow there is a discharge pressure. They are inversely related so if flow goes down pressure goes up etc. Those two parameters are a direct function of the system resistance. Resistance goes up, flow goes down, pressure goes up. With the pump discharge blocked (highest system resistance) you will reach the maximum discharge pressure.
You don't really ever want to run the pump there, especially if it's a positive displacement as it will ruin the pump. Testing it like how was advised is fine though.

By "pump" I meant a gear pump such as is used by most wood splitters. You are thinking of a centrifugal pump like what is used by a water pump.

A gear pump makes x flow at all times (well at a set rpm), doesn't matter the resistance. Without any resistance, the fluid will be at 0 psi.

Edit..didn't see the 2nd page till now, I guess I pretty much wrote the same as Kevin.

 

[Marshy]

this is true of a centrifugal pump, but not for a positive displacement pump. Centrifugal, like a water pump, does have a flow versus head pressure curve. Positive displacement moves a constant amount of flow for any given revolution and the pressure is a result of the load resistance that the fliw is being forced through or against.

Dann it, I forget about that because 99% of the pumps I work with are not positive displacement. Thanks for the correction.

 

[aokpops]

I had 2 pumps go bad . Both times a big loss of power . I bought a few things from Northern they seemed very nice about making right . Your on the edge of making the 16 gallon pump work with a 8 horse . I had a 7 horse would not run a 16 gallon pump .

 

[Mntn Man]

I wonder if the OP ever got it going....