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Thread: Question on Cycle Stop Valves

  1. #1
    DIY Junior Member laffin_boy's Avatar
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    Default Question on Cycle Stop Valves

    I'm trying to put together a parts list for my water system and I have a question about Cycle Stop Valves.

    I have a 100' well where I intend to set a Goulds 5GS series pump @ 70'. Just after the pitless adapter the 1" pvc will feed in this sequence:
    -- the CSV (?)
    -- several canister filters of various types (est total press drop approx 6 - 8 psi)
    -- a 1.5 GPM dole valve (?)
    -- then up 100' to a 2500 gal on the hill

    The system will have very low usage - approx 25 gal / day - so once the tank is filled the pump *should* only run 15 min a day to top up the tank.

    I've added the 1.5 GMP Dole Valve because I need the low flow rate to get sufficient "contact time" for the filter media to do it's job.

    I added the CSV because at this flow rate the 5GS pump chart shows a TDH of 390' which would apply as much as 140 psi to the filters. (BB filter housings are rated @ 125 psi max) I probably don't need the CSV to prevent pump cycling for the little usage it's going to get.

    I've scoured the 'net for info on the CSV and read most of the CSV website but I *still* don't understand how it works which is why i'm posting here. Nor do I understand how the DV works internally either.

    OK, here's my question: The CSV and the Dole Valve are both variable inline restrictions but the CSV maintains (within design limits) a constant output *pressure* while the Dole Valve (again within design limits) maintains a constant flow rate. But do I need them both? Is there another way to reduce input pressure to the filters *and* maintain the 1.5 GPM flow rate I need? If I eliminated the CSV and moved the DV upstream of the filters would the pressure drop across the DV bring the inlet pressures down to a reasonable level? Any way to estimate the drop across the DV?

    laffin_boy

  2. #2
    Moderator valveman's Avatar
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    Put the Dole Valve in front of the filters. This will limit the flow to 1.5 GPM, so a CSV won’t be of any help. After the Dole Valve, the pressure will be controlled by the pressure switch. So you won’t see any more than 40 to 60 PSI on the filters.

  3. #3
    DIY Junior Member laffin_boy's Avatar
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    Thanks, VM.

    OK but what happens when the pump shuts off?

    When it's still filling the tank the pressure at the inlet to the DV is approx 136 psi and after all the filters should be approx 45 psi so the drop across the DV must be the difference less the drop across the filters or approx 85 psi. But when the float valve in the tank closes and the pressure switch sees the pressure rise it shuts off the pump and the only ck valve in the system - at the pump - holds that pressure. But now, with no flow, there's no pressure drop across the DV so what's the static pressure on the filters?.

    laffin_boy

  4. #4
    Moderator valveman's Avatar
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    When the pump shuts off the pressure across the DV will equalize instantly. So if the pressure swith shuts off at 60, after the pressure equalizes you will have about 60.0000001 PSI. There is nothing ahead of the DV than can store and express water.

  5. #5
    General Engineering Contractor ballvalve's Avatar
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    You could put the filters on the downhill side of the tank with a jet pump and tank there, and filter only that portion for home use, using a bypass valve [or tee] for irrigation.

    Using 25 gallons a day with a float valve in the tank means your pump will run maybe once a week. The tank will settle out a lot of crud before the filters and can be blown out from time to time. You could also fill the tank with a simple timer, on and off, if your water use is consistent and suffer some overflow at times.

    I do just that, and also incorporate a 3 way valve to interconnect the outlet of the tank to the inlet from the well, iin the event the outlet pump fails, you can run directly from the well. has been a lifesaver many times.
    Last edited by ballvalve; 05-27-2010 at 12:13 PM.

  6. #6
    That's all folks! Gary Slusser's Avatar
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    Quote Originally Posted by laffin_boy View Post
    I'm trying to put together a parts list for my water system and I have a question about Cycle Stop Valves.

    I have a 100' well where I intend to set a Goulds 5GS series pump @ 70'. Just after the pitless adapter the 1" pvc will feed in this sequence:
    -- the CSV (?)
    -- several canister filters of various types (est total press drop approx 6 - 8 psi)
    -- a 1.5 GPM dole valve (?)
    -- then up 100' to a 2500 gal on the hill

    The system will have very low usage - approx 25 gal / day - so once the tank is filled the pump *should* only run 15 min a day to top up the tank.
    You should not use disposable cartridge type filters or any other type filter between the pump and the tank. No flow control or CSV either.

    Filter after the tank because no matter how much you filter before the tank, you'll still need to filter after it.

    What is the gpm rating of the pump? 5 GS usually says 5 gpm, so why a 5 gpm pump set at like 60' in a 70' well with only 100' to the tank?
    Gary Slusser Retired (= out of business)
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