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Sump Pump Size - too big?

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  • Sump Pump Size - too big?

    I have now gone through 2 sump pumps in 1 years time... The sump cycles a lot. Is this because it is oversized? What happends is that the pump kicks on, sucks the well dry and then shuts off... water then flows in and fills up the pit until it kicks back on. This may happen for a few days after a heavy rainfall... Am I better off with a smaller pump that will stay on longer without cycling so much? I'm not sure which is worse for the pump. I'm afraid that the cycling is ruining switches. I use a (hold your breath) craftsman 1/2 HP pump with a verticle float switch. I don't like the bulb type floats because they get hung up. How are the diaphram switches? better?

    Also, when I install the pump, where should the water line be before the pump kicks on? Too low and it will cycle constantly (I think I have a small stream under the house) and too high may let some water accumulate in the pipes (is that OK?)

    Rob

  • #2
    the pump needs to run longer than the starting circut.
    what are the dimensions of the pit?
    what is the vertical lift of the discharge line? what is the distance the float moves from on to off.
    can you increase this distance without too much standing water back into your basement.
    how much water do you need to move per hour?
    you might have too large of a pump.

    chances are you will need a larger dimension sump pit. this will allow for more water between cycles.
    deeper is typically not the answer. an 18'' x 18'' is usually enough for this pump.
    the pump you have doesn't have an adjustable float switch.

    try to fill in the blanks.

    rick.

    Comment


    • #3
      what are the dimensions of the pit? 20" wide @ 18" deep

      what is the vertical lift of the discharge line?
      10 feet

      what is the distance the float moves from on to off. Bottom of the black plastic pipes is 9" from bottom of the pit

      how much water do you need to move per hour?
      I have no idea how to calculate this accuratly...the zoeller calculation said 23GPM (approx width is 34' length is 54') My downspouts go to the storm drain but I have a feeling I might have a small stream under the house.

      Comment


      • #4
        Plumber Ricks first question is the most important thing we must look at given the symptoms you describe.

        At first read it appears that you may need to change over to a pedestal pump where the motor actually sits well above the rim of your sump. This allows for a float to ride up and down a guide rod that is very easily adjusted for depth. The rod activates the motor which turns the pump down in the sump. You can adjust this rod to allow your sump to fill substantially before it activates your pump. Never let the water get past 1 or 2 inches over the top of the foundation drain pipe entering your sump. Your foundation drain pipes can have some water build up in them without a problem. If they sit full for a long time while water pressure builds against your floor or basement walls then you can have a problem.

        The next thing we must look at is the discharge of your pump line. Does it discharge to a location that allows the water to recycle right back into the pumps sump. i.e, discharge pipe broken outside next to wall or discharges to where water pools and runs down the basement wall directly back into the foundation drain. All the different pumps in the world will not solve your problem if there is a discharge issue.

        After you answer Ricks other questions it may well be deternmined that a different set up is best. But so far a pedestal pump is my recommendation.

        One note: Aside from a wet floor your sump pump is there to protect your foundation and the structural integrity of your home. Hydronic pressure is one of the strongest pressures known to man. Water does not condense, therefore it can push an entire concrete floor up or even lean a home off square to where serious structural damage can occur. Please don't try to save 25 dollars and get by with a cheap pump.

        My personal experience with diaphram switches have usually been negative. So there is no reccomendation from this poster concerning them other than to leave them sit on the shelf in the store.
        Work hard, Play hard, Sleep easy.

        Comment


        • #5
          peccotrice,

          You posted to Rick as I was typing my first reply. As a two finger typist it takes awhile to compose a reply.

          Given the volume of water that you have to move and the fact that you feel you may have a spring under your home I think your sump is under sized. For your particular application I would still reccomend a pedestal pump with a larger pit and a battery back up pump and alarm system.

          Set the activator on the rod to activate the pump when about 2 inches of water is above the bottom of the foundation drain and let it run until the sump is almost empty. Set the battery back up pump to kick on when the water has reached just past the top of the foundation pipe entering your sump.

          Rick is correct that deeper is not always the answer, but in your case with your conditons deeper and wider is probably a very good idea. It is good to see that you have been to Zoellers web site. Pumps are what they do. It is also my opinion that their brand is the one you should switch to.

          It also very important that the discharge issue is addressed.
          Work hard, Play hard, Sleep easy.

          Comment


          • #6
            As already stated, if you are dewatering from groundwater it's important to have a system that will work. To do that you need to identify your source and the GPM requirements. As simple as it sounds a watch with a second hand and a 5-gallon bucket is still the easiest way to figure volume.

            If your sump ends up too deep for a pedestal pump you will need to use a submersible pump with a float switch. I would also add a backup system and a notifier.

            I have a building in Hollywood where my pit was 30' below the the 3rd floor underground parking level. When I first started working there the floor had been flooded for months and no one could park on that level.

            The previous plumber set the pump to turn on at 1' below the top of the pit and the pumps burned out every few months. I found setting the pump to turn on when the water in the pit had 20' of water in it and off at 5' worked best. I also added a high water alarm as a battery backup would not work. So far in twenty years since the repair the pumps have only been replaced once.

            Mark
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #7
              Originally posted by plumber:
              peccotrice,

              You posted to Rick as I was typing my first reply. As a two finger typist it takes awhile to compose a reply.

              Given the volume of water that you have to move and the fact that you feel you may have a spring under your home I think your sump is under sized. For your particular application I would still reccomend a pedestal pump with a larger pit and a battery back up pump and alarm system.

              Set the activator on the rod to activate the pump when about 2 inches of water is above the bottom of the foundation drain and let it run until the sump is almost empty. Set the battery back up pump to kick on when the water has reached just past the top of the foundation pipe entering your sump.

              Rick is correct that deeper is not always the answer, but in your case with your conditons deeper and wider is probably a very good idea. It is good to see that you have been to Zoellers web site. Pumps are what they do. It is also my opinion that their brand is the one you should switch to.

              It also very important that the discharge issue is addressed.
              Is there any way to ID if the discharge is intact without getting out a backhoe and digging everything up? The pump discharges into the gutter drainage into the storm drain at the road.

              Also, why a pedestal pump? All of the homes around me have standard sump pumps.

              Undersized??? I was concerned that the sump pumps the water out too quickly leading to the switch failing (albiet on a craftsman). I'm looking at the 1/3 or 1/2HP zoeller, but will look into pedestals if that's what is reccomended...

              No matter what I'll put in a backup... perhaps both battery and water powered... any thoughts here?

              Rob

              Comment


              • #8
                Originally posted by ToUtahNow:
                As already stated, if you are dewatering from groundwater it's important to have a system that will work. To do that you need to identify your source and the GPM requirements. As simple as it sounds a watch with a second hand and a 5-gallon bucket is still the easiest way to figure volume.

                If your sump ends up too deep for a pedestal pump you will need to use a submersible pump with a float switch. I would also add a backup system and a notifier.

                I have a building in Hollywood where my pit was 30' below the the 3rd floor underground parking level. When I first started working there the floor had been flooded for months and no one could park on that level.

                The previous plumber set the pump to turn on at 1' below the top of the pit and the pumps burned out every few months. I found setting the pump to turn on when the water in the pit had 20' of water in it and off at 5' worked best. I also added a high water alarm as a battery backup would not work. So far in twenty years since the repair the pumps have only been replaced once.

                Mark
                Mark,

                I'm lost with your last paragraph... what size was the pit? Are you saying that I should let more or less water in the pit?

                Comment


                • #9
                  peccotrice,

                  Your sump is undersized not the pump.

                  Under 99% of circumstances I reccomend a standard submersable sump pump. Your circumstance is exactly where I switch to a pedestal. You have a small sump with a large volume of water to move. A pedestal pump will allow you to set the on and off cycles to where you can move the most water with each cycle.

                  Can you see where the water discharges into the storm drain? If not you may need to introduce dye to the water at the very end of the pumping cycle. If the dye shows up in the water coming back in from your foundation lines that will show a discharge problem.

                  One other question. Have you determined that your check valve is working properly? I can't believe I missed this not being mentioned.
                  Work hard, Play hard, Sleep easy.

                  Comment


                  • #10
                    Utah,

                    A thirty foot pit? What size was your pumping system and did you use a tandem system that alternated between each start?

                    About 2 years ago I changed out a tandem system in the Mississippi Bottoms under a hospital and replaced two old 4" Gould (I think they were Gould)pedestals with a couple of 3" Zoellers with the mercury floats. They were wired to work alternatively. Even this high volume system was only 15 foot below the sub basement.

                    They liked this system so well two other hospitals and a very prominent Phone company had me do the same for them within a couple of months.


                    edited part as follows:
                    Actually they might have been Liberty pumps. Another high quality brand made here in the USA by Americans.

                    [ 10-10-2005, 11:28 PM: Message edited by: plumber ]
                    Work hard, Play hard, Sleep easy.

                    Comment


                    • #11
                      peccotrice,

                      You're probably better off ignoring my last two paragraphs. This job was a high rise condo built on a large aquifer. The site had a 24" pit which was 30' deep located on the bottom of a third floor underground parking area. I pumped the pit with a two horse pump which pumped the water to a large holding sump which had two 10 hp pumps (duplex system).

                      The larger duplex system was for some of the storm drains, some of the area drains and all of the dewatering. I was hired because the lower parking level had a foot of water on it for months and the previous plumber could not figure it out. The only water which was being removed was when the lower level flooded to a point the water reached the larger sump. The building was very fortunate they did not suffer permanent structual damage.

                      Mark
                      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                      I never lost a cent on the jobs I didn't get!

                      Comment


                      • #12
                        Mark,

                        It looks like you get a lot of very interesting projects there. If the cost of living were not so cheap here I might even consider moving to the west coast.

                        Nah.

                        But interesting work is often far more rewarding than the ones that are easy.
                        Work hard, Play hard, Sleep easy.

                        Comment


                        • #13
                          plumber,

                          Sorry I was typing as you posted. This was a large (10,000 sq ft) parking garage which was dewatering from a 30' deep pit into a larger sump which had a duplex system in it. I did not have to work on the duplex system only the pit.

                          The building was built with hundreds of 3" foundation drains located 12" above the floor of the garage. All of the drains were draining water on to the floor because the water table was allowed to get too high.

                          The previous plumber installed a Zoeller pump at the top of the pit because he couldn't figure out how to remove the pump which was 30' down in the pit.

                          I used my four wheel drive truck with a bed crane to pull the old pump and riser out. I then dropped a swimming pool draining pump into the pit. Within 24-hours the floor was dry.

                          Then it was a process of testing to find what water level best suited the permanent pump I installed. I also added a couple of float switches attached to alarms and a battery operated alarm which was normally open. That way one alarm sounded when we lost power and another one sounded if we lost the pump.

                          Mark
                          "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                          I never lost a cent on the jobs I didn't get!

                          Comment


                          • #14
                            Originally posted by plumber:
                            Mark,

                            It looks like you get a lot of very interesting projects there. If the cost of living were not so cheap here I might even consider moving to the west coast.

                            Nah.

                            But interesting work is often far more rewarding than the ones that are easy.
                            LOL - Los Angeles has some interesting jobs but I like to get away to play. One of the owners in that high rise was our govenor at the time Grey Davis. Talk about pressure if you screwed up.

                            I use to say I work in Los Angeles but I live in Utah. At one time I would leave LA every Thursday afternoon to go play in Utah and I'd return just in time for work on Monday.

                            Unfortunately now it seems when I go to Utah it is all about water company work. My water company has made a lot of money for a lot of people but it's ruined my playground.

                            Mark
                            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                            I never lost a cent on the jobs I didn't get!

                            Comment


                            • #15
                              Wow... sounds like both of you have some experience...

                              Back to my little problem out here in PA.


                              Is there any way to ID if the discharge is intact without getting out a backhoe and digging everything up? The pump discharges into the gutter drainage into the storm drain at the road.

                              Also, why a pedestal pump? All of the homes around me have standard sump pumps.

                              So my pit is undersized? What size should it be? Is it best to enlarge the it? What effect does this have?

                              I was concerned that the sump pumps the water out too quickly leading to the switch failing (albiet on a craftsman). I'm looking at the 1/3 or 1/2HP zoeller, but will look into pedestals if that's what is reccomended...

                              No matter what I'll put in a backup... perhaps both battery and water powered... any thoughts here?

                              And to confirm... Is it OK to let 1 or 2" or water back up into the black drainage pipe or is that a big no-no.

                              Comment

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