TOH follow-up

Hello, well I found a flow meter and checked the pump. Most I could get was 1000 psi and 0 gpm. I just ordered a new pump. This time it was the easy answer. But I don't regret taking the time to and trouble to make sure. I learned a lot in the last couple weeks and I want to thank you for your advise.
Gratefully Dave

(quoted from post at 13:17:28 08/14/17) Hello, well I found a flow meter and checked the pump. Most I could get was 1000 psi and 0 gpm. I just ordered a new pump. This time it was the easy answer. But I don't regret taking the time to and trouble to make sure.[color=red:cbb5b575cc] I learned a lot[/color:cbb5b575cc] in the last couple weeks and I want to thank you for your advise.
Gratefully Dave

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Well I have learned something also. I had no idea that a pump flow rate of 0 GPM could produce 1000 PSI of pressure :roll:

TOH

whew. that had me scratching my head, glad i'm not alone.

Ok, let me try this again. I closed the valve till it started making the pressure come up. The higher the pressure, the more the flow went down. When valve was closed the pressure read 1000 and the flow meter showed 0. That was at about 2/3 throttle. When I check the pressure with just a pressure gage at idle I had 500psi.

(quoted from post at 19:56:36 08/14/17) Ok, let me try this again. I closed the valve till it started making the pressure come up. The higher the pressure, the more the flow went down. When valve was closed the pressure read 1000 and the flow meter showed 0. That was at about 2/3 throttle. When I check the pressure with just a pressure gage at idle I had 500psi.

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I figured that was what you were trying to say and that is normal behavior. For a constant displacement type pump the output flow rate diminishes slightly as working pressure increases. With the output valve shutoff you are seeing the maximum (deadhead) outlet pressure the pump can produce and for most tractor pumps that should be well in excess of a typical 2000-3000 PSI system working pressure. The 1000 PSI deadhead pressure on your pump is a sure sign that the pump is bypassing internally.

Note that you have to be careful not to damage a good pump when conducting this sort of test. As you close off the valve controlling the output flow and the pump outlet pressure comes up you should stop closing the valve as soon as you get to an acceptable system working pressure. That should be well before the pump is totally deadheaded. If you run a good pump into a deadheaded circuit for more than a few seconds you can easily damage the pump.

If you are getting the proper pump outlet pressure and your hydraulics are still slow responding then you might want too try and measure the flow rate at full system working pressure to see if the pump is partially bypassing. Conducting that measurement without a flow meter is doable but a bit trickier than a simple pressure test.

TOH