Pressure switch rapidly goes on and off at cut in and eventually burns out.

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Tom Luck, Jun 10, 2013.

  1. Tom Luck

    Tom Luck New Member

    Messages:
    5
    Location:
    Marble Falls, TX
    I have a Goulds J10S jet pump connected to a 2500 gallon holding tank, so it always gets water in as long as the tank is at least half full (which it usually is). I have a Square D pressure switch 30/50 psi that also has the emergency cut off in case the water source goes dry; and a Flotec pressure tank set at 28 psi.

    The system initially worked fine, but, it began to trip the emergency cut off. When resetting the pump began to rapidly cut on and off until it finally caught and pressured up. As water was allowed to drain out a nearby hosebib and the pressure decreased it would again power on but with the rapid on and off until if finally caught on and pressured up.

    I have powered off and allowed the tank to drain, and it is light and easily shaken, so it is not water logged and it still shows the 28 lbs. I have also checked the small pressure line that connects the pressure switch to the pump.

    I have already burned out he points in two switches, and put a 3rd one in yesterday and it is trying to do the same thing.

    I would much appreciate any suggestions!

    Thanks,

    Tom L
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,974
    Location:
    NW Ontario, Canada
    Where is the switch relative to the pump and the tank? It should be closer to the tank than to the pump and ideally on a tank Tee.

    Calibrate your air pressure gauge to your water pressure gauge. If one or the other is off, the bladder may be bottoming out on the tank. A jet pump needs pressure to make more pressure and if you shave it too close on the precharge, it will do as you described.
  3. Tom Luck

    Tom Luck New Member

    Messages:
    5
    Location:
    Marble Falls, TX
    Thanks. The switch is actually mounted to the motor part of the pump. It's reads pressure from a small line to the pump housing part of the pump. The pump is mounted on top of the tank. I'm trying to attached pictures, but, I'm not sure I'm doing it correctly. IMG_3385.jpg IMG_3384.jpg
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,462
    Location:
    Lubbock, Texas
    Second guess. Too much air pressure in the tank. Tire gauge and pressure gauge are reading different numbers.
  5. Tom Luck

    Tom Luck New Member

    Messages:
    5
    Location:
    Marble Falls, TX
    I did try lowering the charge pressure. It seemed to help at first, but then it went back to the rapid on/off situation. I might try extending the little pressure line that goes into the switch and extending it down to the pipe on the floor closer to the pressure tank (In stead of it going right to the pump housing). What do you think?

    (And thanks to both of you for replying! I have to get this fixed before my gardens dry up!)
  6. valveman

    valveman Moderator Staff Member

    Messages:
    4,462
    Location:
    Lubbock, Texas
    If letting air out of the tank stopped the rapid cycling, the tank maybe bad. (Water in the air chamber.) But the sensing line for the pressure switch is a long way from the tank the way it is plumbed.
  7. Tom Luck

    Tom Luck New Member

    Messages:
    5
    Location:
    Marble Falls, TX
    Lligetfa, thought you'd like to know, your advice proved to be correct! I did move the switch farther away from the pump and closer to the pressure tank and so far, it is working perfectly! I am thrilled, because up to now, I'd fried two switches and tried just about everything. You're the best! And thanks to all who answered!

    Yours,

    Tom L.



  8. Tom Luck

    Tom Luck New Member

    Messages:
    5
    Location:
    Marble Falls, TX
    Forgot to tell you. I didn't just "extend" the pressure sensing line, as I suggested before (the hardware store guy said that wouldn't make any difference. So, I took the sensor line completely off and put a plug where it used to go into the pump housing and then moved the whole switch and mounted it directly to the pvc connected to the bottom of the pressure tank.
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