partially blocked submersible pump

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Smith333, May 13, 2012.

  1. Smith333

    Smith333 Member

    Messages:
    108
    Our well is about 300ft with a pump positioned about 150ft down. In 1999 the pump was replaced and a sanitary seal put in place. Prior to this, the well cap was loose and bugs got into the well.

    There have been no problems since, until today. I was filling our spa for the first time this season with the garden hose, and the water was noticably cloudy. Looking closely at the suspended solids, it sure seemed like a lot of microscopic bug parts, but I'm not sure. I also noticed it was taking much longer to fill the spa. I observed the pressure gage, and noticed it wasn't able to get beyond 46 psi while the garden hose was going full blast. Normally in this situation, it takes about 45 seconds for a full cycle (pressure switch is 40/60).

    I ran the water for about an hour, and this cleared up most of the suspended solids, but the flow is still greatly reduced compared to usual and the pump continuosly runs with the garden hose going full blast, with the pressure not getting higher than 48 psi until the hose is turned off. My theory is that clump of sediment containing dead bugs somehow broke loose and is now creating a partial blockage. Does this sound plausible, and is there any way to clear a blockage like this without pulling the pump?
    Last edited by a moderator: May 13, 2012
  2. masterpumpman

    masterpumpman New Member

    Messages:
    729
    Location:
    Virginia Beach, VA
    it's possible that particles (in your case bugs) have partially plugged the filter screen on the intake of the pump. If this has happened the only solution is to pull the pump and clean the pump screen.
  3. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,987
    Location:
    NW Ontario, Canada
    You don't say how much pump you have nor how much water. If the water level dropped, the output curve of the pump would also drop. As a result, the pump might not outproduce what you are drawing. Check the static level if you can and give the well time to recover before checking it again.

    If the problem isn't a low water table, get a tanker to drop about a thousand gallons of potable water down the well.
  4. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    Not disagreeing, but what do you think dumping water into the well will accomplish?
    Where I am the water delivery would cost just as much as pulling the pump, and the water would all be lost into the aquifer almost as fast as it was delivered.
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,987
    Location:
    NW Ontario, Canada
    The OP asked:
    He didn't ask if there was a cheaper way.

    As for how fast the aquifer takes the water, it would be about as fast as it can recover. Last year a local well driller estimated it would cost me $1000 to drop a tanker of water down the well. I had it done once before 13 years ago and it blew a lot of crud out the top of the well. Mind you, I pulled the pump out of the hole before he did that.

    I would think the rush of water would rinse off the intake. The crud should either float to the top or sink to the bottom. Depending on the size of the casing and as long as there are no standoffs and a torque arrester, It might be possible to push down a hard line beside the pump and blow the well with a large compressor.
  6. Smith333

    Smith333 Member

    Messages:
    108
    Thanks for the replies. The pump is a 3/4 hp sta-rite. Normally the pump puts out 10-12 gpm, but right now it is maxing out at 7 gpm. It's flowing steadily, and the suspended solids have cleared up somewhat, but the sediment is still unusually high. We don't have the means to pull the pump so we are having someone look at it this week. It has been lowered once in the past 35 years.
  7. Smith333

    Smith333 Member

    Messages:
    108
    The well guy took a look at it this week (actually the same guy who installed the pump in 1999) and concluded (without pulling the pump) it is probably just a seasonal issue that will fix itself, since the working pressure and flow rate are still within the specs of the pump. We'll see.
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