Hello gentlemen, I have onboard alfa laval pu150 lub oil separator, and following problem with it. After start from standstill the separator is running without any problem, is not leaking, keeps the pressure, but after first discharge it starts to loosing oil into the sludge but discharge process looks like this:
1Discharge:
-change over valve changes the position to recirculation
-displacement and bowl closing water are delivered
-discharge, purifier shoots immediately without any problem or abnormal noise
-displacement and bowl closing water are delivered but I can hear that the bowl is not closing
-change over valve changes the position to feed but pressure (PT4) is not increasing
-after a few seconds change over valve goes back to recirculation and purifier is filling with displacement water for a few seconds
-change over valve goes to feed position and purifier starts to deliver but it´s leaking the oil into the sludge
I´ve checked and change all oring and sealing rings, checked pairing disc height, checked belt and clutch, water, air block also checked, water tank clean, and its still losing oil.
Have you ever experienced simmilar situation or have any experience with that type of purifier?
I am looking forward to hearing from you.

Springs, all clean ie ~ no scaling, operating water seals, seals greased so sliding bowl isn't sticky?

Hi Revolver, only thing that I can think of is have you checked the free length of the springs? And is the bowl spinning at the right speed? They usually slow down while sludging, maybe it is slow to pick up speed again?
Big Pete

Thank you guys for reply but the problem is still not solved, there´s no springs in this type of purifier. I suspected bowl speed but from standstill and during first two discharge cycles there´s no problem with leaking. There´s no rpm indicator but current seems to be the same as on the second purifier which is operating well. The bowl surface was cleaned and primed so it´s not an issue of sticking.

Check the water valves and the water pressure, also air pressure for the 3 way valve. does it have nozzles in bowl? Change them out. Is the electrical motor frequency controlled? There could be issues there.

I´ve checked water valves, water and air pressure are ok, 3 way valve operate correctly, nozzles in bowl changed, elec motor is not frequency controlled, the strange thing is that when the pressure pt4 is not raising after discharge there is additional fill of displacement water and after that PT4 increases to normal value.

How is the pressure sensor mounted could it be dirty or the pipes going to it? Did you check that you have the right flow rate/pressure on the water.

Hi! This has been a problem in my case now. Have you checked the pump sleeve at the bottom of the vertical shaft? Please check if there are scales or dirt. I was looking for it and my reliever told me that he had the same issue. Now our purifier is working well