New member's questions. pressure tank sizing

Discussion in 'Pumps and Tanks Well Forum & Blog' started by DeeJay, Nov 16, 2010.

  1. DeeJay

    DeeJay New Member

    Messages:
    11
    Location:
    Glen Williams Ontario
    After a recent leak when a hose came off the pressure tank and flooded my first floor at the cottage, we're about to begin the renos- new floor and some t&g pine replacement on a wall.

    Because my pump is in a cupboard just inside the entrance door, the reno requires removing the cupboard and pump to get at the wall behind it, and while the 30 yr old pump is out, I'm replacing it with a new one a neighbour gave me when he sold and moved back to Michigan.

    My current tank is a non bladder type, which periodically becomes waterlogged, but I'm looking to buy a new bladder model. The cottage has 2 bathrooms and usually has 2-4 people there. I have a new very shallow dug well, and no supply problems, being right on the lake's edge.
    I have three questions.

    1. How do you determine the size of the pressure tank? I've read a lot lately about how a 9.5 gallon model, for example, would be equal to a much larger non-bladder type.
    Is the size mainly determined by available space/footprint, and budget? (HD shows models from 2.1 to 35 gallons.)

    2. I was lucky to hear the pump running when we had our flood and started the cleanup before water rose more than 1.5 inches. However, with all of the damage, I've been paranoid about future leaks, despite 23 years of trouble-free operation.
    I thought that I'd install a switch just inside the door, on the water cupboard itself, to allow for easy manual shutoff of the pump whenever we were going out for a few hours. ( I always depressurize, close the supply valve, and shut off the breaker when leaving for home) The switch would interrupt the 230 v line to the pump.
    Any downside to that, other than forgetting to turn it back on?

    3. I've read here about the value of cycle stop valves to prolong the life of pumps.
    Since this is a seasonal home, would you recommend installing one anyhow? I've been running the pressure range at 40-60 lbs.

    DeeJay
  2. valveman

    valveman Moderator Staff Member

    Messages:
    4,428
    Location:
    Lubbock, Texas
    A 10 GPM pump without a CSV needs a tank that holds at least 10 gallons of water. This would require at least a 40 gallon size tank. With a CSV a 4.4 gallon size tank is all you need. Even though this is a seasonal home and excessive cycling may not be a problem, a CSV will give you “constant pressure” and allow use of a much smaller tank.
  3. justwater

    justwater Well Drilling/Service

    Messages:
    327
    Location:
    FL/GA
    i agree with valveman about the tank size. however, .. i would probably just mount a 3/4hp jet pump to the top of a 20-26gal tank for the easiest install and the smaller footprint and forget about it. little more pump than tank aint gonna hurt a vacation house. if you use quality pump and tank, who knows how long it will last you.
  4. Gary Slusser

    Gary Slusser That's all folks!

    His neighbor gave him a used pump and if he was replacing with new I'd suggest a 1/2 hp instead of a more expensive 3/4 hp, a CSV and a small tank.
  5. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    You can add a air maker of several types to the existing tank and save a tank and some money. The air will be self monitoring and it won't waterlog.
  6. justwater

    justwater Well Drilling/Service

    Messages:
    327
    Location:
    FL/GA
    I agree a 1/2hp would probably be fine, but I sometimes find that (depending upon distance and height above water source) it can be inadequate for 2 bathrooms, dishwasher, laundry, etc. The few extra gpm make alot of difference in being able to do it all and still maintain pressure. that was the only reason I mentioned 3/4... half would likely be fine, but free is probably best. I'm not a fan of CSV at all with smaller tank for house use. Irrigation is fine, but who wants their pump to cycle every time they wash their hands. Everyone to their own I guess.
  7. Gary Slusser

    Gary Slusser That's all folks!

    The draw down gals in the small tank are always used before the pump comes on. And with a CSV, the draw down gallons are always at max when the pump shuts off. I don't think I know of anyone that uses 2.5+/- gals to wash their hands. And a 20 gallon nominal pressure tank at 30/50 psi only has a a couple more gals in it at max but the tank isn't always full when someone uses water.

    And with the less expensive to buy and operate 1/2 hp pump, they would have constant pressure unlike the up/down fluctuations of a regular pressure tank; and too large pump as a 3/4 hp would be for just 2 bathrooms in a cabin that is used sparingly used and probably on weekends when no one should be in a hurry.
  8. valveman

    valveman Moderator Staff Member

    Messages:
    4,428
    Location:
    Lubbock, Texas
    With a CSV and a 4.4 gallon tank you have 1 gallon to use before the pump comes on. The pressure must drop from 60 to 40 as the tank empties before the pump will start. Wash your hands, icemaker fills, rinse a toothbrush, and other small uses will not cause the pump to start. Taking a shower or filling the washing machine, the CSV will hold the pressure at 50 PSI steady until the shower or washing machine is off.

    With a 9.5 gallon tank you only have 2.5 gallons to use before the pump starts. Without the CSV this pump would cycle on and off between 40 and 60 probably 10 times while you are taking a shower.

    With a CSV and small tank the pump starts after using a gallon of water for intermittent uses, but stays running steady as long as someone is in the shower. This is much better than having a larger tank for 2.5 or even 10 gallons of water during intermittent uses, then because there is no CSV the pump cycles on and off multiple times while the shower is running. Then if you have an irrigation system, the CSV eliminates so many cycles during those long periods of low flow irrigation, that a few extra cycles for toilet flushes are a moot point.

    Cycling is what burst the bladders causing waterlogged tanks and rapid cycling that was discussed earlier.
    Cycling is what causes most pumps, motors, capacitors, relays, pressure switches, check valves and other components to wear out prematurely.
    Cycling is the reason larger tanks are needed.
    Cycling causes water hammer that breaks pipe and fittings.
    Cycling causes fluctuations in the pressure for the house and sprinklers.

    The only disadvantage of the CSV and small tank is that your pump runs longer and may use from $2 to $5 extra electricity each month. The CSV does not always increase the electric bill but, even when it does, how much is it worth to solve all the problems listed above?

    A Cycle Stop Valve with a larger tank is the best of both worlds but, the added expense and footprint for a larger tank is rarely worth the investment.
  9. DeeJay

    DeeJay New Member

    Messages:
    11
    Location:
    Glen Williams Ontario
    Thank you for all of the feedback!
    I appreciate the advice re: a CSV and want to buy one.
    The plumber just left, after taking a look at the layout etc.. He took my new 1/2 HP pump with him to make sure he has all of the fittings etc. (1/2 " copper in this place), and suggested a layout for the 8" diameter charcoal filter I'm adding.

    However, he knew nothing about CSV's. I called the major plumbing place in Owen Sound and they didn't know them/carry them. Just called another building supply- no idea. (I gave him this website link- he was very interested!)
    How can this be?
    Are they not widely used?
    Are they mainly a USA usage, vs. Canada?
    Are they new technology, or old and forgotten?
    •What is the approximate cost?
    •Any suppliers in Ontario- Toronto area or up towards Owen Sound?
    •And lastly, if the new pump goes in on Tuesday without a CSV, can it be easily cut into the line afterwards?
  10. justwater

    justwater Well Drilling/Service

    Messages:
    327
    Location:
    FL/GA
    [​IMG]

    heres a basic install of a plastic CSV on a 1/2hp pump (yeah i know, no conduit but its used here on the farm.. sue me). all water from pump must pass through csv first before it goes to tank or anything else, and switch must be after csv or it wont work. you could leave the switch attached to pump, but would need to unhook switch line from pump head and plug hole, then run a longer line from switch to a fitting after the csv (i prefer moving switch). disregard the cut-off valves on the pump's suction, the well is artesian and free-flows like crazy. i'll let the others answer your questions, but thought this might help you get an idea.
    Last edited: Nov 19, 2010
  11. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    You can do the above and use the old tank with a "micronizer" saves the tank.

    Valveman makes the csv - talk to him.
  12. Gary Slusser

    Gary Slusser That's all folks!

    If you add air with a "micronizer" and there is any iron or manganese in the water, the air will oxidize them into particular matter that will line the inside of the pipe from the point the micronizer is installed at and that can lead to serious reduction of the ID of the pipe and thereby reduced flow.
  13. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Micronizer or schrader, its been done for the past 100 years. And you must be speaking only of galvanized pipe, as plastic and pex is not sticky to iron or anything else. Never saw a copper line closed up either.
  14. DeeJay

    DeeJay New Member

    Messages:
    11
    Location:
    Glen Williams Ontario
    Just back from a run to the city to buy a bladder tank for next week. While in HD, I spoke with the head plumbing guy, who had never heard of a CSV, so the mystery continues.
    To avoid changing the dimensions of the pump cupboard, I bought a 19 gal horizontal bladder tank (5 yr guarantee) which includes a mounting bracket on top for the new 1/2 hp pump- same layout as with the old galvanized tank. The next size was 35 gallons, and though I'd have liked it, it necessitated more changes than I want to make, since it was vertical only. And $100 more.
    I'm still going to install a switch on the cupboard so the pump can be turned off easily if we're going out. That way, if something did let loose, there would be only the drawdown of 6 or 7 gallons.
    Ontario members: Any of you find a CSV in Canada?

    The other lesson I've learned, too late, concerns the water line in from the well. When the new well went in, I drilled a 5 inch hole in the cement floor and we dug under the foundation to feed a big O line from the well into the cottage. The water line fed through, dragging a rope in case we need to put another line in someday.
    The big O comes up through the floor about 6 inches, and I mortared it it into the floor. I realize now, that if I had cut the big O off, flush with the floor, it would have served as a floor drain, and the water that was pumping into the cupboard from the loose hose would mainly have gone back down the big O to the well! When the old pump is ripped out Monday, that's one of my first jobs- cutting it off flush.
  15. DeeJay

    DeeJay New Member

    Messages:
    11
    Location:
    Glen Williams Ontario
    Thanks for the feedback, Justwater!
    When the plumber arrives next week, I'll show him your picture, and your explanation.
  16. justwater

    justwater Well Drilling/Service

    Messages:
    327
    Location:
    FL/GA
    No prob. Glad u went for the 19gal instead of a tiny tank. the pump in the pic is sitting on a 19-20gal.. works great. Let us know how it turns out!
  17. valveman

    valveman Moderator Staff Member

    Messages:
    4,428
    Location:
    Lubbock, Texas
    The Cycle Stop Valve was introduced in 1993. So anyone in this business who hasn’t heard of them, probably doesn’t get out much. What’s worse are the ones who have heard of them, and either act like they haven’t or try to discredit them so they can sell you a larger tank and replace your pump more often. Just Google CSV or Cycle Stop Valves and you will find plenty to read. Yes you can always add a CSV later and you will need to. Because a 19 gallon tank only holds about 5 gallons of water and your pump will still cycle on and off a lot without a CSV.
  18. DeeJay

    DeeJay New Member

    Messages:
    11
    Location:
    Glen Williams Ontario
    I did another search and came up with a Canadian connection, through Lloyd Ingram, who I assume is the Cdn. distributor. I've sent him an email for information re: pricing and availability etc..
    However, though I've called and emailed numerous friends/neighbours whom I know to be on wells, plus asked every tradesman I've run into since finding this site, no one has heard of the CSV.
    Looks like what's needed is some advertising up here.
  19. Gary Slusser

    Gary Slusser That's all folks!

    You must not do much water treatment or haven't serviced air injection systems.

    I have seen up to 1" CPVC and PVC, and PE, all but blocked solid with rust. Some with as little as a 1/4" hole for maybe 6-8 feet into a gas off vent tank or inlet to a backwashed filter. It depends on how much iron is in the water. And that is why air injection is not a good choice for water treatment; that's anything with a venturi, like a Micronizer.
  20. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    You are discussing treating weird water with a micronizer. I am discussing adding air to a standard pressure tank. Not comparable.

    Cut open acres of old plastic pipe and never found any crust inside. Never played with Florida water or perhaps something from old faithful geyser in Yellowstone.

    Around here the water treatment guys are like travelling tonic salesmen from 1850. Take your money and run with a piece of crap equipment left behind that causes endless grief. Better to drink bottled water and bathe in the untreated and un-cheated water.
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