Grinder Pump Problems

Discussion in 'Pumps and Tanks Well Forum & Blog' started by DebinFL, Jun 2, 2007.

  1. DebinFL

    DebinFL New Member

    Our home is only 5 years old but we had to replace the grinder pump a little over three years ago (as a note, the original pump which was only a couple of years old, looked as though it had overheated almost to the point of being on fire when it was replaced). Just a couple of months ago, the alarm activated indicating that the pump was not working and we had the plumbing people come out and they said it was clogged with hair, removed that, and the pump resumed working.

    For the past two days, the grinder pump will work for several hours, then the alarm activates because the breaker has tripped. I can reset the breaker and it will trip about four or five times and then the pump will turn on and continue to work normally for several hours before the cycle repeats itself.

    Any suggestions on what could be wrong? Does it sound more like an electrical wiring problem? I can't believe that the pump would need servicing again after only a couple of months. I'm worried that we're damaging the pump or will burn down the house by continually resetting the breaker when it trips multiple times.

    I'd like to narrow down the service calls I have to make since we have to pay an astronomical trip charge for any type of service call due to our location.

    Thanks in advance for any ideas on what I should do!
  2. Bob NH

    Bob NH In the Trades

    New Hampshire
    Consider this a valuable learning opprotunity.

    There are two classes of people who own houses. Five to ten percent of homeowners have enough money that calling someone to service everything is not a financial burden.

    The rest will save $1000 to $3000 per year by learning about their systems, how to diagnose them, and how to fix them. You may need to invest a small amount of that in tools to diagnose and fix your equipment.

    Every pump is defined by 4 characteristics:
    1. Type of pump, which is related to what it is supposed to do
    2. Horsepower of the pump, which is related to Volts and Amps
    3. Flow capacity in gallons per minute or gallons per hour
    4. Pressure ability defined in pressure (pounds per square inch or psi) or in feet of head. 1 psi = 2.31 ft of head when pumping water.

    A grinder pump is usually used for sewage; not for a sump pump to pump out infiltrating water.

    The grinder pump should only be operating intermittently. A typical household uses only about 250 gallons per day of water that goes into the sewer and a grinder pump will typically pump 20 gallons per minute, so it should only be operating less than 15 minutes per day; maybe 30 minutes maximum.

    You should find the make and model number of the pump and determine the GPM and head (pressure) that it is rated for. You should also determine the Amps of electrical current required.

    The rated head, usually specified in feet, should be substantially more (at least 2 times) the difference in height between the sump and the sewer to which it is pumping. If it is a pressure sewer (unusual), the pump has to deliver enough head to pump into the pressure sewer. If the pump has inadequate head capacity, it will never pump out all of the sewage.

    The circuit wiring and the circuit breaker should usually be sized to at least 2 times the nameplate Amps on the pump. If the circuit breaker amps are near or less than the pump Amp rating, the breaker may trip on startup.

    There should be a check valve in the discharge line, or included in the pump, to prevent backflow into the pump. Without a checkvalve, some of the discharged sewage will flow back and the pump will have to run more frequently. The check valve is between the pump and the sewer or septic system.

    Now to the problem.

    You could have a pump that requires more current than the circuit breaker can deliver.

    You could have a pump that delivers inadequate head (pressure) to pump out the collector basin. If you have that, the pump will have to run a long time and may never pump it out.

    Hair should not plug a grinder pump. A good grinder pump should be able to grind up a diaper (but you shouldn't test it with a diaper).

    Compare the Amp rating of the pump with the circuit breaker rating. It is possible that someone replaced the pump with a larger one and the circuit and breaker may be inadequate.

    It is possible that a grinder pump is jammed and difficult to turn. That will cause an overload that will trip the breaker.

    When we find the make and model of the pump, we can be sure that it is a grinder. Someone may have replaced a grinder pump with a sewage ejector pump (cheaper) that is not a grinder. An ejector pump is more easily plugged.

    When you get information on the pump model and amps, and circuit breaker amps, come back and tell us. We may be able to give you more ideas.
  3. DebinFL

    DebinFL New Member

    Thanks so much for taking the time to explain the basics to me. I certainly don't want to be one of those homeowners who have to pay others for every thing that goes wrong! I am hoping that I can put my hands on the replacement pump information because pulling up the pump ranks pretty high on my list of least favorite things I could think of doing!!!

    To some degree, I didn't explain myself too well. The pump does not run continuously. Generally, it trips on for about 15 to 20 seconds and does its grinding job ... usually after 2 or 3 toilet flushings or when the washing machine is draining water between wash cycles. From what I've seen of the tank where the pump is housed, it doesn't look to have a huge capacity ... probably not as much as a bathtub would hold. The pipe that leads to the county sewage line is probably about 2/3 up from the bottom of the tank ... although I guess none of that really has any bearing on the problems we are experiencing?

    We are also very careful about what we flush as we were told when the original pump was replaced that use of flushable wipes had jammed up the pump, causing it to eventually burn up. However, we were also told that these pumps generally have a useful life of at least 8 years so with the first one lasting 2 years and now this one causing trouble after only 3 years, I am concerned that there is a wiring or some other problem contributing to the considerably shorter life span.

    The pump is on its own breaker box with two 20-amp breakers, but wherever the problem is occurring, when the breakers trip, it usually will take 2 or 3 times before the pump will resume working again.

    Thanks again for your suggestions. I really appreciate it! I'll try to unearth the make and model number.
  4. leejosepho

    leejosepho DIY scratch-pad engineer

    I would have the washing machine discharge going elsewhere and only have toilet flushes and possibly the bathroom sink going into that sewage sump. Where your grinder pump would otherwise run only after every two or three flushes (4 to 6 gallons), it presently starts and runs for *many* such short periods of time -- many "short cycles" -- just for one load of laundry. That excessive starting and stopping could easily be at least part of your short-pump-life problem.
  5. Cass

    Cass Plumber

    Wondering where you got the stats for this statement.
  6. Bob NH

    Bob NH In the Trades

    New Hampshire
    It is simply my sense from among the people that have known over the years. Nothing that I can prove.

    It was intended to illustrate the point that you can learn to do things yourself, or you can call someone else whenever a problem arises.

    I have neighbors, friends, and relatives who have spent hundreds of dollars to get sink drains unplugged, replace wax rings on toilets, install ceiling fans, and other minor things that people could learn to do themselves.
  7. bails78ths

    bails78ths New Member

    Duluth, MN
    I am having a grinder pump problem, my pump continuously runs and I do not know why. I do not run an excessive amount of water. The pump and the system are new two months ago and am confused as to what I need to do. pump model and amps, and circuit breaker amps The pump model is a Hydromatic HPG200 Advanced Submersible Grinder Pump
  8. leejosepho

    leejosepho DIY scratch-pad engineer

    What is the size/volume of the sump where the pump sits? The pump starts each time the float switch is activated, and the float switch is activated by the fluid level within the sump. So, it sounds to me like you need a larger sump to keep the pump from starting as often and to then keep it running a little longer each time it does ... and all of that will be good for extending the life of the pump.
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