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Sediment filter before or after pressure tank?

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  • Sediment filter before or after pressure tank?

    I have a submersible pump in my well and I have recently replaced my pressure tank and hot water tank. I plan to install a spin down 100 micron sediment filter. Should it be placed before or after the pressure tank? Half the local "experts" say it should be after the pressure tank and half say it should be before the pressure tank, but no one can really explain why it should be in one place or the other. It seems to me that it should be before the pressure tank. Are there any reasons why that might be a bad idea?

  • #2
    I have 5 micron filters before the water gets to anything. Can't figure why I'd want to let anything into that bladder except the clearest water I can. As I'm a shutoff valve fanatic, I have valves before and after each item so as to be able to isolate it if need be without affecting the rest of the sytem. I would recommend before the pressure tank.

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    • #3
      Common sense should dictate that it goes before the tank, otherwise the sediments would settle to the bottom of the tank, negating the entire purpose of the filter, not to mention eventually fouling the tank.

      However,, it should not be between the pump and the pump pressure switch.

      Comment


      • #4
        The water inlet pipe (1") enters the house a couple of inches above the basement floor and continues 3' across across to the pressure tank. The setting on the pressure tank is for the pump to turn off at 60 psi and back on at 40 psi. I don't have any information about the submersible pump that is actually in the 200-300 foot well. I don't know if it is ½HP or 2 HP and I have no idea what the water pressure is coming into the house. Currently, there is no pressure relief valve in the system (except on the hot water tank) and the first shutoff valve is after the pressure tank. There is manganese (0.05, I think) in the water and the hardness is 11 grains. I replaced the pressure tank and hot water tank because they were severely corroded. I've only been in this house for a couple of months.

        I asked the plumber to add a 90 degree elbow and a 3' vertical section, another 90 degree elbow and a 3' horizontal section, and another 90 degree elbow and 3' vertical section back down to the floor level. I wanted the sediment filter to be hung vertically in the horizontal section that would be 3' off the floor, 5 diameters from the upstream elbow (leaving room for a second 10 micromometer filter), shut off valves in each of the vertical sections upstream and downstream of the filter, and drains at the bottom of each of these vertical sections also (currently, the first shutoff valve in the system is after the pressure tank).

        The plumber who came to the house argued with me, telling me that this is all the wrong way to do it and that he's never seen a filter placed before the pressure tank. He left without installing it. I've since consulted three other plumbers and the technical person from the manufacturer of the pressure tank who all insist that the sediment filter should be after the pressure tank. Only one of them could offer any reason to back up his position. He said that the pressure tank and the pump are "matched" and that putting anything in line between them would mess it up and deregulate everything. Two other plumbers (but they don't make house calls) and the guy from Rona who sold me the filter said that the filter should be before the pressure tank.

        I don't know anything about plumbing and pumps and I don't have any experience living in a house with a well, so I've been trying to imagine what problems might arise from putting the sediment filter before the pressure tank. I can only think of three possibilities, but I have no idea if they make any sense at all: (1) The pressure from the pump could exceed the pressure rating of the filter, 150 psi; (2) The pressure drop across the filter could result in the pressure tank not filling to 60 psi; (3) The setting on the pressure tank would have to be readjusted if the inline filter was installed upstream from it. Does any of that make any sense? Is there anything to worry about? If I'm going to argue with the plumber and insist that he put it before the pressure tank, I want to be sure that I'm not going to be creating other problems, or at least know how to deal with them.

        Comment


        • #5
          While it obviosly is not possible to read the date plate on the pump while it is at the bottom of a 300 foot well, we can theoretically determine the Horse Power by meauring both the LINE VOLTAGE and AMPERAGE to the pump.

          Using the formula P= E x I where P= watts, E = Volts and I = Amps, you could then multiply voltage x amps to determine Watts. By then using the constant 1 Horsepower mechanical = 746 Watts electrical we can then determine the working horsepower by simple division.

          Given that the pump is pressently at a depth of between 200' and 300' and the static head pressure of water is approximately .5psi/ft. vertical, we can estimate the pumps current output pressure to be 100psi to 150psi + 60psi line pressure for the house which would then be a range from 160psi to 210psi minimum if measured at the pump discharge port. (60psi distribution line pressure + the physical weight of the water standing in the pipe rising from the pump to the house - (static head pressure ))

          In this case the plumbers are correct. There should be no valve or device between the pump and the pressure regulator that could interfere with the pressure regulator sensing the true discharge pressure from the pump.

          There are two availabe options at this point, one, install the pressure regulator on a tee before the sediment filter or 2, leave the pressure control on the tank (required by some local codes) and install the shutoff valve and sediment filter on the downstream side of the pressure tank. In this configuration the pressure tank should also be fitted with a manual blowdown valve (boiler cock) to periodically purge sediment from the tank.

          The main shutoff valve Must Be placed after the pressure tank, but before the sediment filter. A second valve may be placed on the downstream side (after the filter) to permit isolating the filter for service.

          Also, keep in mind that if you have copper piping, there can be no direct coupling of copper to Galvanized Iron pipes, vessels or fittings. All transistions from Galvanized metal to copper MUST BE made by means of Dielectric Unions, Dielectric nipples or a 6" hardened bronze nipple to prevent corrosion.

          Comment


          • #6
            Put a "TEE" between your pump and your filter. On this "TEE" install your pressure switch. then install filter after switch. Your "PUMP" controls your switch, to keep it operating properly you CANNOT put anything between your pump and switch. In this filter I would put a 20 micron cartridge then install another filter after "ALL" tank plumbing and before the rest of your house. In this filter I would put a 5 micron cartridge and you should be fine.

            Comment


            • #7
              Sediment filters are a joke! They should NEVER go before the tank or the pressure switch. When it plugs up (and it will) it can lie to the switch and nuke your pump. If you actually have sediment in your water, call your well driller and find out why you have sediment.

              All the advertising that goes on these days about your tap water has most homeowners scared to death about their water. How many fatalities have you heard about concerning people drinking tap water???

              If you want to help a manufacturer of sediment filters get a bit wealthier, go ahead and buy one. If not, they will not help your water one bit.

              Comment


              • #8
                A possible fix for pre pressure filter

                Originally posted by LazyPup View Post
                While it obviosly is not possible to read the date plate on the pump while it is at the bottom of a 300 foot well, we can theoretically determine the Horse Power by meauring both the LINE VOLTAGE and AMPERAGE to the pump.

                Using the formula P= E x I where P= watts, E = Volts and I = Amps, you could then multiply voltage x amps to determine Watts. By then using the constant 1 Horsepower mechanical = 746 Watts electrical we can then determine the working horsepower by simple division.

                Given that the pump is pressently at a depth of between 200' and 300' and the static head pressure of water is approximately .5psi/ft. vertical, we can estimate the pumps current output pressure to be 100psi to 150psi + 60psi line pressure for the house which would then be a range from 160psi to 210psi minimum if measured at the pump discharge port. (60psi distribution line pressure + the physical weight of the water standing in the pipe rising from the pump to the house - (static head pressure ))

                In this case the plumbers are correct. There should be no valve or device between the pump and the pressure regulator that could interfere with the pressure regulator sensing the true discharge pressure from the pump.

                There are two availabe options at this point, one, install the pressure regulator on a tee before the sediment filter or 2, leave the pressure control on the tank (required by some local codes) and install the shutoff valve and sediment filter on the downstream side of the pressure tank. In this configuration the pressure tank should also be fitted with a manual blowdown valve (boiler cock) to periodically purge sediment from the tank.

                The main shutoff valve Must Be placed after the pressure tank, but before the sediment filter. A second valve may be placed on the downstream side (after the filter) to permit isolating the filter for service.

                Also, keep in mind that if you have copper piping, there can be no direct coupling of copper to Galvanized Iron pipes, vessels or fittings. All transistions from Galvanized metal to copper MUST BE made by means of Dielectric Unions, Dielectric nipples or a 6" hardened bronze nipple to prevent corrosion.
                I keep clogging up my check valve with sand and getting water hammer when the pump shuts off because the valve does not close. Cleaning it fixed the problem for a couple of days. I see,there are centrifugal sand separators that use no filter element and can be purged by opening a bottom valve. I,would instalI it before the switch. have two questions. Do they work? Would this affect the pressure switch? I am mostly concerned about the first question.

                Comment


                • #9
                  You didn't say what kind of pump you have or where this check valve is. The only filter that might work is a Laval seperator or it may be under another name by now. They were a centrifugal device with no moving parts that spun the sand to the bottom where it could be dumped out. These devices work on normal sized sand. Powder sand that tends to stay suspended in the water for a few seconds is not removed. It takes a pretty good flow to make one of these things work. Jet pumps generally don't benefit from them.

                  Since these have no actual filter element to plug up, these are installed before the tank.

                  Comment


                  • #10
                    Originally posted by Speedbump View Post
                    You didn't say what kind of pump you have or where this check valve is. The only filter that might work is a Laval seperator or it may be under another name by now. They were a centrifugal device with no moving parts that spun the sand to the bottom where it could be dumped out. These devices work on normal sized sand. Powder sand that tends to stay suspended in the water for a few seconds is not removed. It takes a pretty good flow to make one of these things work. Jet pumps generally don't benefit from them.

                    Since these have no actual filter element to plug up, these are installed before the tank.
                    All I know is that it is 1/2 hp , down 250 ft. the check valve is at one end of the diaphragm style tank's manifold and the other end is the output to the strainer filter. It is absolutely a stock set up. Since I posed the question I learned several things. Centrifugal sand separators are a dime a dozen, are made to solve my problem and come with and without auto purge. Even Whirlpool offers one with adjustable cycle auto purge powered by a 9 volt battery. The big name in sand filters seems to be Lakos. I found all kinds of good info. Fill jar with sand laden water. Shake. Time how long it takes for sand to settle to bottom of jar. Over three minutes and it is too light for a centrifugal filter. I was at 55 seconds. Correctly size filter to pump gpm. With pressure tank an indirect method is needed. It involves timing pump cycle and measuring collected water from a tap. The only thing I don't know is how well they work. If it works well there should be a lot less sand in the strainer. Have you actually used one? Thanks.

                    Comment


                    • #11
                      Yes I have used them. Claude Leval invented them years ago. They worked for coarser sand quite well. But again, the flow rate really had a lot to do with it. He made many different sizes of them to compensate for water flow and pipe sizes. I used a couple of them with success and then tried one on a well which had very fine sand. That sand went right through like the separator wasn't even there.

                      Sand is a big problem with well water. It can clog plumbing, it can ruin pump impellers and eventually shut off your water if there is enough of it. The best fix is to try and repair the well or install a new one.

                      Comment


                      • #12
                        I know this is an old thread, but I have a question on a different solution to this problem. What if you put a sediment filter before the pressure tank, but in addition put an additional pressure switch before the sediment filter that had a higher pressure setting, so that it was basically always on unless the pressure got some amount higher than the pressure switch on the pressure tank was set for? That way the water gets filtered, the pressure switch on the pressure tanks would normally control the pump, but in the event of a filter failure or clog, the additional pressure switch would shut the pump off when the pressure got too high.
                        Does this sound like a feasible solution?

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