loss of pressure

Discussion in 'Pumps and Tanks Well Forum & Blog' started by awgeez, Jul 4, 2011.

  1. awgeez

    awgeez New Member

    Messages:
    5
    Location:
    Richmond, OH
    i have a weird problem. Lerts start with everything normal, 60 psi at the guage. turn on the water and the water flows normal, guage pressure starts to drop, all is well. Until the guage reaches cut in, 40 psi. thats where it gets strange, as soon as i hear the pressure switch close, the guage drops to 0, then the pump builds the pressure back up to 60. the faucet that was turned on during this slows to barely flowing for 3 to 4 seconds while the pump starts pumping back towards 60 psi. the pressure tank has no water coming out of the schrader valve and is showing 40 psi with the water off and the tank bled off.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Sounds like you run out of reserve too soon. Did you calibrate the air gauge with the water pressure gauge? Let a little air out of the bladder.
  3. awgeez

    awgeez New Member

    Messages:
    5
    Location:
    Richmond, OH
    run out of reserve? im not sure what you mean by that. with a stopwatch, the water will run for 58 seconds with out the pump running. and put out around 6 gallons (overflow a 5 gallon bucket) when the pump comes back on it will take 26 seconds to reach cut-out, 60 psi. where im confused is that why, when the switch closes does the pressure drop so far and suddenly.
  4. awgeez

    awgeez New Member

    Messages:
    5
    Location:
    Richmond, OH
    and, when the pressure drops at cut-in, the flow is almost nothing. as the pump builds pressure, the flow and pressure return. im thinking that the screen in my submersible is plugged or the pump is buried in the mud.
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Normally the air precharge in a bladder tank is set lower than the cut-in pressure so that the tank still has a little bit of reserve. If you cut it too fine, the bladder tank will run out of reserve before the pump delivers. Did you calibrate the gauges to be sure they are both reading the same?

    If you pop the cover off the pressure switch and use your thumb on the pressure plate to manually start the pump when the tank pressure drops to 45 PSI, does it still dive to zero? I'm guessing it will not as the tank would still have a net reserve of 5 PSI.
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Pumps generally don't like starting from 0 PSI and can be slow out of the gate. Do you have a second checkvalve at the tank? If so, you might try removing it.

    Also, 26 seconds of run time is a bit short. Tanks are normally sized so that the pump runs for at least a minute.
  7. awgeez

    awgeez New Member

    Messages:
    5
    Location:
    Richmond, OH
    i am by no means dumb, but sometimes i do need things explained in little bitty words. this would explain why adding air made the problem worse, D'OH
    thanks brother, seems to be a-ok now.
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Glad I could help.

    If, over time the cut-in pressure tends to drop, suspect that the pressure switch is building up with minerals under the diaphragm and may be time to replace it. This is usually when the reserve runs out and the symptom you describe manifests as normally the amount of precharge air never increases on its own.
  9. awgeez

    awgeez New Member

    Messages:
    5
    Location:
    Richmond, OH
    yes, there is what appears to be a check valve just before the pressure switch. if i understand how this all works, the tank and pump were fightin each other, which is why the gauge read 0(40mius 40=0), until the pump overpowered the tank. right?
  10. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    For some reason some people like to put a checkvalve at the tank as a backup to the one on the pump, thinking that if one is good, two is better. Not so. The problem is then the checkvalve at the pump doesn't have constant pressure against it to help hold it closed and it could leak. When the one at the pump leaks, the water column falls back toward the well and depending on length of pipe and static water level can create a vacuum in the line. The pump then doesn't have pressure to push against right away and also the column of water will hammer the checkvalve at the tank.

    The gauge read zero because the reserve ran out while the draw continued meanwhile the pump flow on start hesitated because it was starting from 0 PSI.
  11. Texas Wellman

    Texas Wellman In the Trades

    Messages:
    522
    Location:
    SE Texas-Coastal
    Your problem sounds pretty straightforward to me. Empty all the pressure from your tank (water pressure). Take a reading with a guage. If the gauge reads 40 psi or above, release enough air so that the pressure reads about 2 psi less, or about 38 psi. Problem solved.
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