Tom_Veatch
Platinum Member
Out mowing the other day and after a couple of hours, happened to lay my arm on the housing for the FEL joystick. Wow, was it HOT! And it's in a convenient place to rest the forearm.
The FEL is an aftermarket addon package installed by the dealer when I bought my grey-market Yanmar. Looks like it was plumbed by cutting the supply line from the pump and rerouting the flow through the FEL valve and back to the supply line. I guess that makes it an "open-center" or maybe an "open-center power beyond" valve installed in series if I understand what I've been reading.
My question is, why couldn't the valve be replaced by a "closed-center" valve and the series arrangement be changed to a parallel configuration. Insert tees in each of the supply and the return lines and plumb from the supply to a closed-center valve. Return flow from the valve would be plumbed to the tee in the tractor's return line.
Sorry to bring this up again since I've read in other threads that such a parallel circuit would stop everything from working because of free flow through the parallel branch. But, those other threads seemed to assume the parallel branch is through an open center valve. What if the added/replacement valve were closed center?
A point made in one thread was that in such a parallel arrangement, at least part of the flow would be diverted from downstream uses when the FEL was actuated. But, even in a series arrangement, the flow energy used by the FEL won't be available downstream since it's the lower pressure return from the FEL that is being supplied to the downstream applications. Obviously there's something I'm not understanding.
As is probably very obvious, there isn't much hydraulic oil soaked into my hands. About all I know is what little I've read, and I'm not real sure I understand that. All I'm sure about is that FEL control housing was uncomfortably hot and it would probably be much cooler if the full output of the hydraulic pump didn't constantly flow through it. (Also wouldn't have to worry about quick-disconnects deadheading the pump output if/when the FEL is dismounted)
The FEL is an aftermarket addon package installed by the dealer when I bought my grey-market Yanmar. Looks like it was plumbed by cutting the supply line from the pump and rerouting the flow through the FEL valve and back to the supply line. I guess that makes it an "open-center" or maybe an "open-center power beyond" valve installed in series if I understand what I've been reading.
My question is, why couldn't the valve be replaced by a "closed-center" valve and the series arrangement be changed to a parallel configuration. Insert tees in each of the supply and the return lines and plumb from the supply to a closed-center valve. Return flow from the valve would be plumbed to the tee in the tractor's return line.
Sorry to bring this up again since I've read in other threads that such a parallel circuit would stop everything from working because of free flow through the parallel branch. But, those other threads seemed to assume the parallel branch is through an open center valve. What if the added/replacement valve were closed center?
A point made in one thread was that in such a parallel arrangement, at least part of the flow would be diverted from downstream uses when the FEL was actuated. But, even in a series arrangement, the flow energy used by the FEL won't be available downstream since it's the lower pressure return from the FEL that is being supplied to the downstream applications. Obviously there's something I'm not understanding.
As is probably very obvious, there isn't much hydraulic oil soaked into my hands. About all I know is what little I've read, and I'm not real sure I understand that. All I'm sure about is that FEL control housing was uncomfortably hot and it would probably be much cooler if the full output of the hydraulic pump didn't constantly flow through it. (Also wouldn't have to worry about quick-disconnects deadheading the pump output if/when the FEL is dismounted)