Adjusting unloading on 2-Stage log splitter Pump

   / Adjusting unloading on 2-Stage log splitter Pump #1  

jejeosborne

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GC SERIES HIGH/LOW PUMPS
I have this pump on my splitter and am reading that this pump has an "integral adjustable unloading valve. I am guessing that this is an adjustment that dictates when the second stage would kick in. When looking at the performance chart there are dotted lines showing the output of the pump at different settings. My question is how to make this adjustment. I wish Haldex had online pump manuals. My hope is that I can make the first stage stay in longer since my engine is not being tasked before it switches to the 2nd stage. Anyone done this? If so where can I get instructions?
Jeff
 
   / Adjusting unloading on 2-Stage log splitter Pump #2  
I got the same pump as yours on my wood splitter, except mine is a John's Barns but it is the same thing. Theses pumps give you 11 or 16 gpm under 700 psi and over 700 psi 6 to 8 gpm up to 3000 psi.

First, you must check your engine, if it will be able to handle this rise of pressure. Usually the factory setting for the first stage is 700 psi. If you got a 8 or 9 hp on a 11 gpm pumps, just forget it, the engine will dies on the effort. But if you got a 13 hp, it will works just fine.

Second, to modify the factory setting, you just unscrew the plug and put small steel washers under the release pressure spring. Be careful to put only 1 washer at the time and check your pressure. Do not go over 900 psi on your new setting.

You will notice a deferent in traveling speed of your ram. It will goes faster.
In my case i did not modify mine, I fund the speed just fine.

http://www.hbus.haldex.com/products/documents/hi_lo_pg_rev1203.pdf
 

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   / Adjusting unloading on 2-Stage log splitter Pump
  • Thread Starter
#3  
1300356, 1300357 & 1300159 Performance Chart

Here is the performance curve for my pump. I have a 7 HP engine. Looking at the chart, my engine should be able to handle an 800psi first stage. I just want take advantage of all the HP of the engine. The second stage is only about 3.5 gallons/minute which is considerably slower. Anyone every tinker with this setting?
 
   / Adjusting unloading on 2-Stage log splitter Pump
  • Thread Starter
#4  
I talked to a hydraulic representative today from Haldex and got the answer. I was plesantly surprised to find that it is a very easy task. He said to remove the cap on the inlet side of the pump. Under the cap is a slotted screw. Turn clockwise to increase pressure and you know the rest. He suggested turning 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. I always run the engine full throttle and plan to play with the setting this weekend.
 
   / Adjusting unloading on 2-Stage log splitter Pump
  • Thread Starter
#5  
I finally got time to make the adjustment. I first turning the screw all the way in which resulted in the engine being killed at the end of the stroke or when testing by cross-cutting a piece of wood. I was able to leave the cap off while making the adjustments to put the setting at the exact place to maximize the engine HP.

I must say that I am very happy I took the ten minutes to make this adjustment. The splitter only went into 2nd stage on one piece of wood that was very ugly in about 30 minutes of splitting. What an improvement to effeciency for production and fuel.
Jeff
 
   / Adjusting unloading on 2-Stage log splitter Pump #7  
I have a 16gpm barnes pump on my wood splitter .When I put a piece of knotty wood in it it will get op to the wood go to 2000psi and stop does not drop down pressure does not go up what do I do to make it work
 
   / Adjusting unloading on 2-Stage log splitter Pump #8  
It sounds like your system relief valve is set at 2000 PSI. With out knowing what therest of your system components are it would be difficult to try and help diagnose where this valve is and if you could safely increase this pressure setting.
 
   / Adjusting unloading on 2-Stage log splitter Pump #9  
The low pressure on that pump is about 650 to 700 psi. Full rated pressure is 3000 psi

The load is what cause the pressure to build, or you can simulate a full load by fully extending or retracting the cyl, and the relief valve on the valve will activate.

So, if it will not get to 3000 psi, then the valve pressure relief is not set, or you don't have a load equivalent to 3000 psi.
 
   / Adjusting unloading on 2-Stage log splitter Pump #10  
I have a splitter I built that has a 12 briggs 16 gpm pump 5x24 cyl to split with a 3x14 on the log lift two open center splitter valves hooked together a filter on the return at the tank the valves are tied toegether out of one in the other and split the lines so I can use one valve at a time and I have a gauge on the pressure side that goes to 3000
 
 
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