Hydraulic remote levers

[kjg26]

I just got my new to me Kioti DK55 home. As not to mess anything up can somebody please explain to me where I should leave the had draw remote levers when not in use. My limited understanding is that there are several positions they can be placed in. Unfortunately I don't have Immediate access to the tractor right now. I will be back out there tomorrow

 

[ericm979]

The most common valves work just like the loader valve but only in one direction. They're spring loaded to stay in the neutral off position. Some have a detent at the end of the travel in one direction. That can be a float position (like many loader valves have- push up and it'll click into detent and let the loader float up and down) or it can be a fully open position. You'd use that to run a hydraulic implement that has its own valves, like a log splitter. If you have a valve like that and leave it in the detent with nothing connected, it will "dead head"- you'll hear the relief valve squealing as it opens to let the pressure into the tank. It's the same as if you curl the bucket all the way and keep holding the joystick when the bucket reaches the end of travel. When you're deadheadding, the hydraulic cylinders after the relief valve that's open won't get significant pressure or flow. There's a relief in the loader valve but there can be others.

 

[davrow]

As Eric says, self-centering valves (levers) should be left centered.

But! All attachments should be grounded before turning off engine.

And all connected valves should be moved to remove pressure from the lines after turning off the engine.

 

[kjg26]

So once engine is shut off move the levers....is that even if im not using the valves or only when theyre in use.

 

[davrow]

So once engine is shut off move the levers....is that even if im not using the valves or only when theyre in use.

Only when they have attachments on them.

When I set my FEL bucket down it is never perfectly level on the ground. After turning the engine off and moving the lever around it dumps/curls until it is flat. That relieves the pressure in the lines so it is easy to disconnect or reconnect the hoses when switching implements (e.g. when taking bucket off and putting grapple on).

 

[ericm979]

I don't bother moving the levers until I want to disconnect a quick connector.

 

[davrow]

I don't bother moving the levers until I want to disconnect a quick connector.

That's reasonable, but it leaves pressurized fluid in your lines... so could lead to leaking and/or rupture. Likely? Perhaps not. But absolutely prevented by starting the habit from the first.

 

[ericm979]

The pressure would only be from gravity acting on the bucket or whatever and that's going to be a lower pressure than when operating the cylinders.

 

[CobyRupert]

The pressure would only be from gravity acting on the bucket or whatever and that's going to be a lower pressure than when operating the cylinders.

Would it? Maybe my understanding is too simplistic, but:

Exploring the "or whatever" aspect:

What if: Sun shines on the hose that retracts cylinder, but cylinder is already fully retracted. Couldn't pressure build up exceed the pressure that system normally sees? Even if not fully retracted, in order for cylinder to move because of fluid expansion in the lines, doesn't the opposite side of the cylinder need to discharge fluid, but is trapped by valve, thus pressure beyond normal could build up?
I don't know anyway to avoid this, unless valve can be left in float?

 

[ericm979]

The system relief valve is at around 2200 psi. You can consider that the highest pressure under normal operation. Hoses are rated to 3000 psi or more.
Water's coefficent of expansion at 90 degrees C is about the same as oil's. I found a calculator that calculates the pressure rise in a sealed vessel full of water (but it didn't say at what temperature). Going from 32 degrees F to 100 would create 2200 psi according to this calculator. Hydraulic hoses are not perfectly rigid so theres some loss there due to the vessel expanding. There may be other factors I'm not considering, I'm not that kind of engineer. It's more pressure than I thought but doesn't exceed normal operating pressure with that temperature rise. Maybe you could see more of a rise from the depths of winter to the height of summer there in NY.