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Thread: Sediment filter before or after pressure tank?

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    austin is offline Handyman
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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?

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    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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    LazyPup is offline Deity
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    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.

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    austin is offline Handyman
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    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.

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    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.


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    nahi is offline New Member
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    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.

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    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.

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