2013 47m putz randomly short stoking
Pnw pumper 02-10-2020
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I’ve got a 2013 putz randomly short stoking 

when I watch the proxy lights cycle it’s always 2 n 3

ive changed the proxy wires n the proxy switch’s 

doesn’t make a difference  any ideas??


PUMBO 06-09-2020
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Short stroking occurs when oil becomes trapped at the 'top' end (the furthers point from the biggest hydraulic hoses of differential cylinders and doesn't reach the path to return back to the loop because the piston inside the cylinders does not reach orifices where the stroke compensators return oil back to the loop.

So what happens is it becomes trapped? You have to stroke correct the pump manually by holding down the stroke correction button until the cylinder piston is forced to its end position. where pump maxes out at 350Bar on "both cylinders".

Your problem of randomly short stroking, Seeing as most modern machines have a fixed position for the proximity switch mounted on the pumping cylinder its not possible to adjust the point where the prox switch gets its signal, the problem more occuring at low speeds and less prevalent at higher pumping speeds.

You can however increase the likelihood that at least one cylinder piston can return oil back to the loop by getting to the check valve where another may not by ensuring there are 4 stroke corrector check valves with return pipe (2 at each cylinder) see red arrow in pic. Most Putzi's have 2 one at the top of one cylinder and one at the bottom of another cylinder. So a retrofit of 4 (independent) check valves vs 2 may assist in this problem.