Pressure testing difficulties

[J_J]

J_J
My M7040 has performed any hyd task I've asked it to do therefore I will be SMART and leave all relief valves set exactly the way they came from the factory.

Again I'll ask if the tech manuals don't mention "master relief valve" then why do you call FEL a master relief valve when in fact you admitted that the valve set for lower psi will pop off 1st which anyone who understands hyd's know this is a fact. ??????

PS: Skyhook has a good question whats the difference between "relief ports" and "Work port relief's"
I hope you have a good day,Jim


'

If a manual does mention master relief or main relief valve for that moment in time, it may be temporary, but if you add another valve with the relief valve set lower upstream, the other relief is not the master, the lower setting relief is the Main relief for the total open center hyd system.

Jim, I respect your intelligence, but don't even try to insult mine.

I do have some knowledge that I gladly share.

 

[J_J]

Only use the term, master relief if you know how the term is used.

ARE WE FINISHED YET?

 

[Tx Jim]

If a manual does mention master relief or main relief valve for that moment in time, it may be temporary, but if you add another valve with the relief valve set lower upstream, the other relief is not the master, the lower setting relief is the Main relief for the total open center hyd system.

Jim, I respect your intelligence, but don't even try to insult mine.

I do have some knowledge that I gladly share.

J_J
If asking you to explain/clarify one of your statements is insulting you so be it!! Now your stating the main relief is the relief valve with the lower psi setting which could or could not be the FEL valve that you allured to when I 1st questioned your Master relief valve statement. All I'm trying to do is insure that information posted on tractor discussion forums is CORRECT information.
Jim

 

[J_J]

I don't know why you persist, but here goes.

If the first valve in the pump flow path has a relief setting lower that the other relief valves, then it is the main relief. Even call it the master relief if you want.

If say a remote valve has a 2500 psi setting, and the FEL has a 2700 psi setting, and the 3pt has a 2600 psi setting, which valve will limit the 3pt pressure. The remote relief valve.

In this situation, the FEL will relieve at 2600 psi.

If you use the remote valve, that circuit will relieve at 2500 psi.

If you use the 3pt, it will relieve at 2500 psi, why, because the remote valve sets the pressure downstream.

So, if your tractor came from the factory set at say 2500 psi on the 3pt, and whoever installed the FEL set that valve to 2450 psi, then your FEL valve will limit the pressure to 2450, and you would lose some potential on the 3pt.

Take a look in your tractor and FEL manual and tell me the relief settings, and I will give try and to give you an answer as to how and why.

The logic would to protect the hyd circuit.

Also think of this. Does the 3PT cyl have a better pressure rating than the FEL cyl?

It depends on the relief valve setting as to which valve relief will relieve.

 

[The Fred]

In this situation, the FEL will relieve at 2600 psi.

Because power beyond is blocked off during any FEL valve operation correct?

Thanks JJ, very informative as usual. NOT to change the subject but often times when my FEL will not quite lift the load I am trying but if I run the tractor WIDE OPEN (2950 RPM) the FEL will lift the load. I am guessing because the relief valve cannot handle the volume of oil asked to go through it?

Regards, Fred

 

[J_J]

The answer is that when operating the FEL, the FEL valve is the only valve using the fluid and the cyl expended fluid flows through the OUT port. The other valves downstream don't have enough fluid to do anything.

However there are some valves that will pass cyl expended to the PB flow path.

 

[Tx Jim]

I don't know why you persist, but here goes.

If the first valve in the pump flow path has a relief setting lower that the other relief valves, then it is the main relief. Even call it the master relief if you want.

J_J
You're the one that initially called the FEL valve the "Master valve" which is what caused me a question you.
Good day,Jim

 

[Egon]

(( In this situation, the FEL will relieve at 2600 psi.

Because power beyond is blocked off during any FEL valve operation correct?

Thanks JJ, very informative as usual. NOT to change the subject but often times when my FEL will not quite lift the load I am trying but if I run the tractor WIDE OPEN (2950 RPM) the FEL will lift the load. I am guessing because the relief valve cannot handle the volume of oil asked to go through it?))

The relief better be able to handle all flow the system will see or something may break.

 

[J_J]

Wow, I believe I have explained everything about that in detail.

Call it a relief valve, main relief valve or master relief valve. You should be able to relate to the use of the terms.

It's no big thing, just saying

 

[MHarryE]

I didn't see it resolved in the prior posts but gage and gauge have been used interchangeably for eons. It's like colour and color, harbor and harbour. The best dictionaries will explain they are just spelling variations, neither one incorrect. In the case of gage and gauge it is not British and American versions - it's just however you want yo spell it. I like gauge myself because the word is longer, seems like more precise like a gauge should be.

On the minor part of the question, unless closing the valve prevents oil from getting to a relief, the lowest set relief controls an open circuit just like I think JJ is trying to say.