# splitter pump not not going into low stage



## merc_man (Oct 16, 2014)

Hello
my dad has a home made splitter he is working on and is having trouble with the pump not going into the low range when splitter is put to work. He bought a new concentric rockford inc. pump rated for 5h.p. 2 stage. the motor is a 7 h.p. and when he splitts a tougher peice of wood it boggs out and stalls , not going into the low range. if anyone has any ideas on what to try or what the problem may be please let me know.

thanks Randy.


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## homemade (Oct 16, 2014)

What pressure are you running out of the valve. Usually the valve has an adjustable relief built into it so it will relief the pressure before the engine stalled. For example if your pump is only rated for 1500 psi and the relief won't open till 3500 psi it will continue to build pressure until the motor can't turn anymore. 

Pressure gates and more info on parts (valve brand, cylinder size)


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## muddstopper (Oct 16, 2014)

Have you put a pressure gauge on it to see how much pressure your building? Without a gauge, you will just have to set the relief by ear. Back the relief off until the engine doesnt bog, that might protect some of the important parts, like seals, hoses and pump. A gauge would also be handy to adjust your lowflow high pressure, it could be that the relief is set to high for the pump to kick down into the lowflow high pressure side of the pump.


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## merc_man (Oct 16, 2014)

He checked and said ther was no adjustment on the valve. He gonna get a guage and see what the presure is first of the week.


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## jgoodhart (Oct 16, 2014)

I kind of had the same issue except I use a John Deere 40 (more than enough HP) and a flat belt drive to run the splitter and the pump wouldn't go to low flow high pressure and jump the belt off. It turned out the cylinder rings were shot and it wouldn't build enough pressure to operate the pump, Rebuilt my cylinder and it worked ever since.


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## wndwlkr (Oct 16, 2014)

sounds like your pump needs adjusted. should be a cap nut right next to the inlet on the pump. It should kick down around 700-900 psi.


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## muddstopper (Oct 17, 2014)

Post a pic of the valve. It should have a relief on it, if it doesnt, then you need to add one. The relief might or might not have a cap nut over the screw. What size is the pump? How big is the cylinder. You really havent gave enough info.

This valve has two reliefs, http://www.surpluscenter.com/Hydrau...M-LOG-SPLITTER-VALVE-W-AUTO-DETENT-9-7724.axd the nut beside the handle is the main relief, and the one at the rear(that you can barely see behind the rear port) is for setting the detent. 

A motor spool valve such as, http://www.surpluscenter.com/Hydrau...-SD4-HYDRAULIC-MOTOR-CONTROL-VALVE-9-8464.axd doesnot have a relief, but when used in a system, there will be a seperate relief placed somewhere between the valve and pump.


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## merc_man (Oct 17, 2014)

Here is a pic of the pump


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## merc_man (Oct 17, 2014)

Sorry i dont live close enough to go get all the info.


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## merc_man (Oct 17, 2014)

Heres a little better pic


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## merc_man (Oct 17, 2014)

This is the pump he baught for it.


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## muddstopper (Oct 17, 2014)

I cant see a relief on the control valve. Looks like the cylinder is on the small side. It could be that the pump is building maximum pressure, but the cylinder doesnt provide the tonnage. Since the pump doesnt give a pressure rateing, flow in high pressure/low flow is 2.9gpm. It takes 6hp to pump 2.9gpm at 3000psi. At 3500psi, it takes 7hp. I suspect that the combination of cylinder size(you didnt say how big it is), no reliefs on control valve, and a engine just about undersized, is the cause of the bogging.


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## merc_man (Oct 17, 2014)

The motor is a 7 h.p. on a 5h.p. pump will try to get the cylinder size for ya.


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## muddstopper (Oct 17, 2014)

merc_man said:


> The motor is a 7 h.p. on a 5h.p. pump will try to get the cylinder size for ya.



I understand that. My point is that without any relief, your pump could be maxing out on pressure. Your pump description didnt supply any PSI numbers. Generally, most of the 2stage pumps top out at 3000psi. and 3600rpm. Your pump is rated for 4000rpms, which I have never seen on a two stage log splitter pump. I dont know the pressure rateing. Just because a pump is rated of xxxpsi, doesnt mean it will stop building pressure at that point, it can build pressure until it burst. The pump will not build any pressure until it comes under load. as the load increases, the PSI climbs and with a small bore cylinder, the psi will climb higher/faster than it would on a much larger cyl. That is where a relief comes into play. The relief lets excess pressure bypass to prevent damage to the pump, busted hoses, blown cyl and valve seals. If the pressure is not relieved, it can continue to build until something breaks. In your case, the engine is the weak link, I suspect that the pressure is building to the point the motor cannot pull the pump, which causes the bogging and killing of the engine. If the pressure didnot kill the engine it could be possible to burst the pump or destroy other parts. I am doing a lot of guessing and the only way to know is to install a gauge and test the pressure. Without some sort of relief valve, simply installing a larger hp engine will only mean something else will break before the engine stalls.
Once the gauge is installed, you can do a full cyl extention or retraction and see just what the pressure is when the engine stalls. If this is indeed the case of to much pressure, I would not use the machine until I could install a external relief valve. Continue to operate without a relief will cause serious damage to the machine. If you need more splitting force, the next step would be to install a larger cylinder. You might find it cheaper to just purchase a regular wood splitter valve with built in relief than to buy a relief valve and the fitting/hoses to make it work.

I looked up the pump and found the specs. Its a 13gpm pump rated at [email protected] and [email protected] psi. Max pressure is 3000psi. It takes 5hp at the 2.9gpm-2500psi numbers. At 3000psi it needs 6hp. Now without a relief, it is possible that the pump could be producing more than 3000psi, at 3500psi, it would take the full 7hp of your engine, and that assuming the engine is producing at 100% efficently, which it probably isnt. Continuing to run the pump at excess pressures will produce a pump failure in the near future. Install a gauge, check pressures and add a relief or change out the control valve for one with a build in relief. It will save you money in the long run. If after you install the gauge you find the pump isnt building excess pressure, then you can trouble shoot the engine.


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## merc_man (Oct 17, 2014)

Thanks muddstopper he is gonna put a guage on it and get a pressure test first of the week. I really appreciate the help from ya. Wish i knew more on how it all works.


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## triptester (Oct 17, 2014)

The relief adjustment screw is located under the plug above the return elbow.

http://www.energymfg.com/pdf/16445x.pdf


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## muddstopper (Oct 18, 2014)

triptester said:


> The relief adjustment screw is located under the plug above the return elbow.
> 
> http://www.energymfg.com/pdf/16445x.pdf


Good catch, I should have seen that. Now the interesting part is that the relief is preset 2000psi from factory and a max range of 2500psi. His engine should pull that without any serious bogging. Rereading the first post, he says it boggs out and stalls. I am now wondering if its the engine that is stalling, ( which is what I thought he was saying),or the cylinder that is stalling. I think that issue needs to be clarified before going any further. If the cylinder is what is stalling, and the engine continues to run, it could just be a matter of the relief being set to low, or to small a cylinder for the wood being split. If it is indeed not shifting into lowflow/high pressure, then he might need to adjust the pump to the the 650psi high flow/ low pressure. Remove the cap on the inlet side of the pump. Under the cap is a slotted screw. Turn clockwise to increase pressure. Turn the screw all the way clockwise to the stop and see if the engine can handle it. If not then back it out a little and try again. Run the engine full throttle and plan to play with the setting until you find the limit for your engine. You will find that the higher you can run the pressure on high flow side, the less the pump will kick down into low flow/high pressure and the faster your splitter will work. If you engine is actually already what is bogging, you may have to turn the screw counter clockwise to lower the unloader pressure.. It is best to use a pressure gauge, but you can do this by ear. If its killing the engine, just turn the screw out until it no longer kills the engine. You should adjust the relief setting on the control valvle first before trying to adjust the unloader valve on the pump. The load is what will cause the pressure to build, you can simulate a full load by fully extending or retracting the cyl, and the relief valve on the valve will activate. If it will not get to 2500 psi, then the valve pressure relief (on control valve) is not set, or you don't have a load equivalent to 2500 psi. With a gauge installed, pressure will be at a minimum until you activate the lever on the control valve, Once lever is activated, pressure should climb on the gauge until the cyl is fully extended or retracted, at which point the pressure will climb rapidly to the relief setting. Watch the gauge, it should jump from the settings on the pump unloader valve (650psi), to the setting on the relief (2500psi). You may need to split a round or two to actually see the pressure spike as the spike can be pretty fast

I will just add, that I have never had to adjust the relief on the control valve or unloader relief on a pump that was new out of the box. Usually if the reliefs need adjusting, its because someone has already been messing with them. Usually the factory guys have it pretty close, not saying mess ups dont happen, just that it is unusual when it does. I also usually use large bore cyls and bigger hp engines than the minimums required. If you have the hp to pull the pumps and cyls that create more than enough force, the factory relief setting will usually take care of themselfs.


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## merc_man (Oct 18, 2014)

it is the motor that is stalling out.


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## muddstopper (Oct 18, 2014)

merc_man said:


> it is the motor that is stalling out.


Let us know what the pressures are once a gauge is installed. Do you know the bore of the cylinder. I suspect that if the valve was new and hasnt been messed with, it could just be a matter of adjusting the unloader pressure on the pump. For a quick test while you wait for a pressure gauge, just undo the cap screw on the pump and screw the adjustment screw out a couple of turns and see if that helps. Still need a gauge to determine actual relief pressure setting.


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## wndwlkr (Oct 18, 2014)

wndwlkr said:


> sounds like your pump needs adjusted. should be a cap nut right next to the inlet on the pump. It should kick down around 700-900 psi.


opcorn:opcorn:


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## Mike from Maine (Oct 18, 2014)

On the pump, not the valve, there should be a hex head cap next to the inlet.





Remove the hex head cap and there will be an adjustment screw... This adjusts the pressure at which the pump goes into low flow. Turn it out a couple turns.


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## showrguy (Oct 18, 2014)

my splitter was doing the exact same thing as the OP's..(years ago)
finally got tired of dikin around with it, so i tore the pump apart.
the keyway had broken inside the pump and caused all kinds of scoring, 
new pump, and she worked like new again..


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## muddstopper (Oct 18, 2014)

muddstopper said:


> Have you put a pressure gauge on it to see how much pressure your building? Without a gauge, you will just have to set the relief by ear. Back the relief off until the engine doesnt bog, that might protect some of the important parts, like seals, hoses and pump. A gauge would also be handy to adjust your lowflow high pressure, *it could be that the relief is set to high for the pump to kick down into the lowflow high pressure side of the pump*.





wndwlkr said:


> sounds like your pump needs adjusted. should be a cap nut right next to the inlet on the pump. It should kick down around 700-900 psi.



wndwlkr, are you trying to make a point?


Mike from Maine said:


> On the pump, not the valve, there should be a hex head cap next to the inlet.
> 
> 
> 
> ...


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## merc_man (Oct 22, 2014)

my dad got a guage to check it. what should the pressure be set to? should he put i on the line going from the valve to the cylinder?

thanks


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## muddstopper (Oct 22, 2014)

The best place to place the gauge is in the pressure line between the pump and the control valve. Putting the gauge between the valve and the cylinder will only give you a pressure reading in one direction, just depending on which cylindr line you put it in.


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## Mike from Maine (Oct 23, 2014)

Low enough that it doesn't stall the engine.


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## merc_man (Oct 23, 2014)

He tried a presure test on the line going from pump to valve. He had lots of presure but the motor woukd jot start do ro the presure build up. Guess this is normal? Think he said he had 2000 psi what to check next?


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## merc_man (Oct 23, 2014)

He also tried line from valve to cylinder and got 2000 psi.


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