Great video , i would like to know , Can i deadhang the pump from the system if from the pump discharge it goes not only to a relief valve but a control block that contains a relief valve, a main spool etc, thanks.
Hi. Many thanks for the video. But many hydraulic systems do not have the flowmeter already installed onto the relief valve. Any suggestions how to install a flowmeter onto a relief valve? Or is there another way to check the condition of a pump?
You are correct! In fact, almost no systems have flow meters installed in the relief valve tank line (and I've never seen it done by the OEM - always aftermarket in the rare instances I have seen them). I would recommend it in any system. Of course, sometimes the flow meter cannot be installed in the relief valve tank line because it is not exposed. Sometimes the relief valve is connected directly to the reservoir. In a case like that, the flow meter should be installed in the pressure line immediately downstream of the pump with some way to deadhead the system and force the flow through the relief valve. Yes, there are other ways to check a pump - measure case flow, measure current draw, compare the temperature of the suction line with the case drain line. All of these are good checks, but none of them are as definitive as comparing the flow from the pump under load with that under no load.
GPM Hydraulic Consulting I appreciate your prompt and worthy reply and hope to see many more videos on your channel. You guys are really respectable and kind. What you do here is priceless and you deserve all the best. Best Regards.
Quick question. So if you would open the flow control after the system checks out would the pressure now drop because of the load? My system reads 2600 psi with no load but when hooked up to the cylinder for an 4 post auto lift it falls to 800 psi. Cylinder has been rebuilt so that isn’t the cause. Just wondering why the lift seems to be running slower. Thank you for your help. Dan
Hi Dan. Thanks for your question. Yes, the pressure would drop once you open the flow control, assuming there are no other flow controls in the system. If the only resistance downstream is the load, then the pressure would drop to load pressure. However, if there are any flow controls limiting speed, the pressure would stay at the pump compensator setting since the stroke of the pump would be limited by the flow controls on the actuator. Hope this helps!
Yes, if the flow drops significantly (more than 10% on most industrial machines) when the pressure is increased to normal system pressure, the pump is bad and must be replaced.
nice vid, what happens with a gear pump, if one has rotation wrong, mine has no pressure and little flow as I ran it counter to what I should have as there was no rotation arrow on the schematic, only when I opened the tank could I see the rotation arrow on the pump, I suspect shaft seal blown?
Thank you for your kind comment! Yes, it is quite likely that rotating in reverse has blown your shaft seal. The pressure rating on most pump shaft seals is quite low, often below the pressure necessary to circulate oil through the system, let alone attempt to move any load. The good news is that gear pump shaft seals are relatively inexpensive and easy to replace.
@@JackWeeks oh, well, I changed pump and had to change plumbing in the tank, alas flow, no pressure I took the spindles from the solenoid valves, I checked the relief valves, I have no compensator and do not know what to do next, I knocked the tank drain valve and lost 60 litres of oil on the shop floor .3 weeks now and run out of ideas, thank you Jack
@@stuarth43 Yeah, pressure problems are seldom caused by the pump (though that IS usually the first thing that gets changed). Try isolating the pump from the system, deadheading it across the relief valve. This should give you pressure. From there you should be able to eliminate components until you find where you are losing resistance. If you have a schematic, I will be glad to look it over and see if anything comes to mind. Email it to me at jack@fluidpowerlearning.com
+Azur Hrustic A cracked pump housing is caused by excessive shock in the system. Any well designed hydraulic system will have a pump isolation check valve immediately downstream of the pump. Its purpose is to ensure that any flow goes from the pump to the system and never from the system into the pump. Thus it will protect the pump from shock as well as keep any back-flow from turning the pump in reverse. If you don't have a pump isolation check valve, try installing one. If you do have a pump isolation check valve, chances are that it has become contaminated and will need to either be cleaned or replaced. Hope this helps.
I have new oil gear pump PVG100 When fixed in system was not able increase the pressure more than 2800psi with manual delivery valve shut in and I don't know to adjust the pump because it has no pressure compensator valve instead it has a maximum volume stop valve have adjust the pressure can somebody help me out
Its a fixed pump probably. So it's delivering maximum flow and with the resistance you have in the system that equals to 2800 psi. If you want more pressure you need the pump to deliver more flow, but that might not be possible with your pump if Im reading you right.
Great video , i would like to know , Can i deadhang the pump from the system if from the pump discharge it goes not only to a relief valve but a control block that contains a relief valve, a main spool etc, thanks.
Hi. Many thanks for the video. But many hydraulic systems do not have the flowmeter already installed onto the relief valve. Any suggestions how to install a flowmeter onto a relief valve? Or is there another way to check the condition of a pump?
You are correct! In fact, almost no systems have flow meters installed in the relief valve tank line (and I've never seen it done by the OEM - always aftermarket in the rare instances I have seen them). I would recommend it in any system. Of course, sometimes the flow meter cannot be installed in the relief valve tank line because it is not exposed. Sometimes the relief valve is connected directly to the reservoir. In a case like that, the flow meter should be installed in the pressure line immediately downstream of the pump with some way to deadhead the system and force the flow through the relief valve.
Yes, there are other ways to check a pump - measure case flow, measure current draw, compare the temperature of the suction line with the case drain line. All of these are good checks, but none of them are as definitive as comparing the flow from the pump under load with that under no load.
GPM Hydraulic Consulting
I appreciate your prompt and worthy reply and hope to see many more videos on your channel. You guys are really respectable and kind. What you do here is priceless and you deserve all the best.
Best Regards.
@@Oyuncubabavedora Thank you!
I don't know anything about this.
Seems to me I could test how fast the tracks move in the air and then drive up a hill. That's load and no load.
@@jesseakers7298 lol go for it and if the machine drives you in a circle we’ll you’ll know for sure you have a bad pump..🤣
Thank you for these video I'm going to school for maintenance tech.
Quick question. So if you would open the flow control after the system checks out would the pressure now drop because of the load? My system reads 2600 psi with no load but when hooked up to the cylinder for an 4 post auto lift it falls to 800 psi. Cylinder has been rebuilt so that isn’t the cause. Just wondering why the lift seems to be running slower. Thank you for your help. Dan
Hi Dan. Thanks for your question. Yes, the pressure would drop once you open the flow control, assuming there are no other flow controls in the system. If the only resistance downstream is the load, then the pressure would drop to load pressure. However, if there are any flow controls limiting speed, the pressure would stay at the pump compensator setting since the stroke of the pump would be limited by the flow controls on the actuator. Hope this helps!
@@JackWeeks Thank you sir for your help.
So if it did go down the whole pump needs to be replaced? Please lmk
Yes, if the flow drops significantly (more than 10% on most industrial machines) when the pressure is increased to normal system pressure, the pump is bad and must be replaced.
nice vid, what happens with a gear pump, if one has rotation wrong, mine has no pressure and little flow as I ran it counter to what I should have as there was no rotation arrow on the schematic, only when I opened the tank could I see the rotation arrow on the pump, I suspect shaft seal blown?
Thank you for your kind comment! Yes, it is quite likely that rotating in reverse has blown your shaft seal. The pressure rating on most pump shaft seals is quite low, often below the pressure necessary to circulate oil through the system, let alone attempt to move any load. The good news is that gear pump shaft seals are relatively inexpensive and easy to replace.
@@JackWeeks oh, well, I changed pump and had to change plumbing in the tank, alas flow, no pressure I took the spindles from the solenoid valves, I checked the relief valves, I have no compensator and do not know what to do next, I knocked the tank drain valve and lost 60 litres of oil on the shop floor .3 weeks now and run out of ideas, thank you Jack
@@stuarth43 Yeah, pressure problems are seldom caused by the pump (though that IS usually the first thing that gets changed). Try isolating the pump from the system, deadheading it across the relief valve. This should give you pressure. From there you should be able to eliminate components until you find where you are losing resistance. If you have a schematic, I will be glad to look it over and see if anything comes to mind. Email it to me at jack@fluidpowerlearning.com
អគុណបងthank
i have had three pumps break in the case/body... where to seek the problems? what comes first to mind?
+Azur Hrustic A cracked pump housing is caused by excessive shock in the system. Any well designed hydraulic system will have a pump isolation check valve immediately downstream of the pump. Its purpose is to ensure that any flow goes from the pump to the system and never from the system into the pump. Thus it will protect the pump from shock as well as keep any back-flow from turning the pump in reverse. If you don't have a pump isolation check valve, try installing one. If you do have a pump isolation check valve, chances are that it has become contaminated and will need to either be cleaned or replaced. Hope this helps.
+GPM Hydraulic Consulting of course it helps :) will install the check valve first thing in the morning :) thanks a lot!
I'm curious about compasentor
I'm glad to hear that! Many people misunderstand the compensator. I hope your curiosity drives you to learn as much as you can. Happy troubleshooting!
I have new oil gear pump PVG100 When fixed in system was not able increase the pressure more than 2800psi with manual delivery valve shut in and I don't know to adjust the pump because it has no pressure compensator valve instead it has a maximum volume stop valve have adjust the pressure can somebody help me out
Its a fixed pump probably. So it's delivering maximum flow and with the resistance you have in the system that equals to 2800 psi. If you want more pressure you need the pump to deliver more flow, but that might not be possible with your pump if Im reading you right.
@@magnusbendixen6155 hy good evening
I just replece the PTO and the hydraulic pump and Dont have any presure
If the pressure is very low, I would check the system relief valve first.
@@JackWeeks ok thanks
Sir still not able to understand may be next time
Good🇧🇩
Please wear safety glasses. And INSIST trainees do the same.
Great videos though!
bullcrap, I'm 75 worked lathes engines, all my life, only worn glasses grinding steel but never with alu
Calm down son you’re doing fine
Is it me or did I jusy see it decrease😄