Hypro D50 Problem

Discussion in 'Pesticide & Herbicide Application' started by KACYDS, Feb 7, 2009.

  1. KACYDS

    KACYDS LawnSite Senior Member
    Posts: 559

    Hopefully someone can shed some light..........

    Just rebuilt a D50, with new diaphragms, o-rings, and Accumulator diaphragm.

    Used it all this week and noticed yesterday that the pressure gauge is not staying steady. It is rapidly going back and forth between 100 & 200 psi. Also noticed that there is more vibration from the pump.

    It continues to spray fine, doesn't seem to lose any pressure at the tip of the gun.

    I'm thinking that one or more of the check values might be bad. Also the oil in the sight glass is still clean. Not milky.

    Before I tear it apart, AGAIN, I was wondering if anyone has had this problem before or has any input.

    Thanks, Kris
     
  2. Ric

    Ric LawnSite Fanatic
    Posts: 11,946

    KACYDS

    Did you replace the surge suppressor and add the proper PSI of air pressure???
     
  3. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,826

    Did you charge the accumulator chamber with air after reassembly? I think the air charge is 20% of operating pressure. The tire valve on the top makes working on these pumps a snap.
     
  4. KACYDS

    KACYDS LawnSite Senior Member
    Posts: 559

    Ric,

    If you talking about the diaphragm under the red top, yes I did change that.

    Ric & greendoctor,

    I did put 40 psi in it. Rechecked yesterday and there was still 40 psi in it.

    Any other suggestions?
     
  5. greendoctor

    greendoctor LawnSite Fanatic
    Posts: 8,826

    If the intake or discharge valve is hung up or malfunctioning, that will cause pulsation as well. It can be as simple as some trash stuck in the valve.
     
  6. KACYDS

    KACYDS LawnSite Senior Member
    Posts: 559

    Thanks for the info.

    I will take it apart Monday afternoon, need it for a couple of hours Monday morning. Not to worried about hurting anything. The pump is 23 years old.
     
  7. Ric

    Ric LawnSite Fanatic
    Posts: 11,946

    Green

    We are thinking alike. Beside a stuck or slow closing valve, a bad diaphragm can cause the same problem.

    KAYDS

    While not generally necessary to change with every Diaphragm replacement, I like to at least take the check valves a part and polish the SS surfaces. Because I spray a lot of oxidizing material, I find the check valves do get ruff and leak.
     
  8. KACYDS

    KACYDS LawnSite Senior Member
    Posts: 559

    Ric,

    Thanks for the good info, I will definitely look into that.
     
  9. Ric

    Ric LawnSite Fanatic
    Posts: 11,946

    KACYDS

    Be careful taking them out. They will break and can be very hard to get out unless they are taken out each time you change Diaphragms. They are plastic holders with a SS spring and two SS parts the seal together by the spring. The plastic holder comes a part and you can polish them with 400 grit wet dry sand paper. All 4 are identical and just fit in reverse to make the liquid flow one way only. Should you mess up just one, they are sold as replacement group of 4. I keep old working Check valves for that just in case.
     
  10. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 11,785

    New check valves are not real expensive. I think I paid $11.00 apiece for the valves on my smaller D-252. And they are fairly easy to remove. Check them out and make sure no broken springs or incorrect assembly. If anything is worn--replace it. Make sure no o-ring is pinched or improperly assembled. One failed valve will cause the problem you mentioned as stated above. One other thing--the pressure regulator. If the valve seats here are worn or pitted or have debris caught--pressure will be poor. Look for pits or corrosion damage to the pump houseing itself. If some area has corroded away the o-rings will not seal. Check and replace as needed. Also check your filters and suction side of input
     

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