I don't know everything...Wilkins 420

Discussion in 'Irrigation' started by SprinklerGuy, Jul 26, 2007.

  1. Went to a client's rental home yesterday....her 420 Freezeproof LOL PVB was leaking...I had a repair kit and proceeded to replace parts....

    First the check valve....still leaks...then the white retainer ring doohickie...still leaks...then the poppet...leaked a little....then th e bonnet and oring...stopped leaking.....except when a zone came on...then it leaked as if it were lower than the heads..like an ASV would....wtf?

    Anybody familiar with this PVB...?

    It was almost 8PM and I had had enough of the day...so I passed until later today,.....lil help Please? What could cause this..what am I missing on this PVB I have only seen once...

  2. irritation

    irritation LawnSite Gold Member
    Posts: 3,305

    I know Wilkins had a recall on them a few years ago.
    I've found that leaving both ball valves half open usually keeps them from dumping and doesn't affect the pressure.
  3. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    Haven't had that problem yet. But I have only worked on a few. Are the zones stretched and exceeding GPM, causing it to leak/dump? Slap in a 765 and be done with it :)
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,307

    Even the older Wilkins 720 will dump at low pressures. Different sort of poppet arrangement.
  5. Washer was missing on the plastic retaining doohickie thingamabobber....
  6. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,136

    What..you guys don't have a spread sheet for "washer inspections?"
  7. I couldn't retrieve it today..blackberry service was down in that area
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Damn those retaining doohickie thingamabobbers... first a space shuttle... now a backflow device... what next???

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