Frozen Cistern

Discussion in 'Homesteading Questions' started by HydroMan, Jan 23, 2005.

  1. HydroMan

    HydroMan Member

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    I have a small cabin on 20 acres in North Idaho. Right now it is just a weekend place, but I intend on moving onto it permanently in the next few years. It is off the grid with solar and wind power. It has a year round creek with excellent head which I intend on tapping for hydro-power in the long range future.

    My water supply is from a 125 ft well wih a DC submersiable pump pumping the water into a 500 gallon inground concrete cistern. The cistern has a 6 inch thick access cover with the top of the cover at ground level. The cistern is housed in an uninsulated wooden shed, 2x6 construction with metal roof.

    When I arrived yesterday after being away for 3 weeks I had very little water pressure coming out of the faucets. Suspecting a frozen pipe I first checked the main gate valve located in a crawl space located 4 feet below grade right outside the peremeter of the house. From what I could tell there was very little water coming through. What was flowing sounded kind of like there might be a mix of ice/slush in the lines. I have a small DC booster pump located right after the main house gate valve and very little water was coming through the hose to pump when I removed the hose to check for flow. So I determined that the gate valve and plumbing downstream into the house was not frozen. I installed a stop/waste drain system which I use to drain all the house plumbing between visits. So it appears that is working. Temps dropped to about minus 10F about a week ago and until this week's pineapple express moved in the temps were consistently in the low 20s in the day and teens at night.

    So next I checked the cistern. I lifted the concrete access cover off the top of the cistern, thinking the cause of the problem was upstream of the house. The water in the cistern was topped off, but I found the top 4-5 inches was frozen solid. However since the water underneath was not frozen and cistern outlet is at the bottom of the tank, I am still baffled on why I am not getting any pressure at the house or where the blockage might be. The piping between the cistern and the house is buried 4 feet below grade so I would not expect it to freeze. The cistern outlet valve is 4 feet below grade in a 2ftx2ft wide vaulted box stuffed with styrofoam and batting insulation. I am thinking it could be partially frozen there, but access is difficult so I have not been able to remove it to check it out.

    So my questions are:

    1) Is there a way I can keep the water in the cistern from freezing? I know a lot of people use those electric livestock heater/deicers, but I need a non electric solution since I am off the grid relying on solar and wind to charge my batteries and I cant be running the generator every time it gets cold. I figure if it would help if I insulated the shed but with all the airspace in there, I doubt it would keep the cistern from freezing. I am thinking I need to somehow insulate the access cover. I have thought of hay or straw but I dont want to atract rodents slow close to my water supply.

    2) Any thoughts on where the freeze/blockage might be between the cistern and the house. Is the cistern outlet valve the most likely culprit? If so, how can I insulate it better? It is already 4 feet below grade with the vault fully stuffed with insulation.

    3) I am also thinking I need to find a way to protect the plumbing located in the 4 ft below grade crawls space outside the house where my the booster pump, 1 gallon air bladder booster pump and all my valves are located. These are all drained when I am not there, but I am thinking there is enouch cold air down there to freeze this plumbing when I am, particularly overnight. Being below grade I beleive it is well insulated on 3 sides, but there is only 6 inches of earth over some horizontal logs at the ceiling and the access is through a sheet of plywood. Again I need a non-electric solution, so heat tape is not really an option.

    If I had built the cabin, I definitely would have designed the plumbing system differently. I need to find a way to make reasonable modifications to make what I have work during the winter.

    Please accept my appreciation in advance for any advice all you "experts of real life experience" can provide me.

    Thanks,
    Dave
     
  2. Cyngbaeld

    Cyngbaeld In Remembrance Supporter

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    Hi Dave. Too many ? for me to have a go at, but I'll try to answer a few anyway.

    It is possible that the ice on top is preventing enough air getting into the cistern so you have a partial vacuum that the small pump is pulling against.

    Have you tried putting a propane heater in the cistern house? One of the camping style on top of a 40# bottle should work ok.

    Insulation is good! In a closed poly type cistern unless the rodents can chew through the pipes or wiring, they won't damage your water supply. I never had problems with rodents in my cistern even with loose insulation on it.

    Also, on the cistern house, can you install a south facing window to bring in solar heat?
     

  3. SRSLADE

    SRSLADE Well-Known Member

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    correct. break the ice.
     
  4. Darren

    Darren Still an :censored:

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    My guess is also the ice not allowing air to reach the top of the water. As was posted, that creates a vacuum that won't allow gravity to drain the water. A cheap solution is one of those fish tank air bubblers. All you need to do is to drop the bubble stone into the bottom of the cistern. The rising air will keep a small patch of the water surface ice free and allow the water to drain into the house. If you don't have a power outlet near the cistern, hook the compressor up in the house and run a long hose to the cistern. I've done that with a pond. It kept one spot ice free all winter.

    The best part is those little air pumps don't draw much current.
     
  5. Steve

    Steve Well-Known Member

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    Cyngbaeld is most likely correct about the ice cap creating a vaccuum underneath that the pump cannot overcome.

    Back in the '70s when I lived on a small farm in northeastern North Dakota, this happened to us and my landlord just drilled about a 1/2" diameter hole in the ice cap to let air through. He tied a rope around the drill so that it hung with the bit down. Then he plugged it in and turned it on and locked the trigger lock. Then lowered it down to the ice and said to let it eat the ice slowly or the drill body will counterspin. We had water after that.

    Then the next time the water hauler delivered water, he just dumped it on top of the ice cap and it finally broke up.

    Hope this helps.
     
  6. Rick

    Rick Well-Known Member Supporter

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    Hi Dave

    Is there a way to lay in a plywood ceiling, that you could remove in June?

    Can you fit a fat piece of PVC pipe in such way as to use the pipe to allow an airway for the water?

    As for the areas away from the tank that may be freezing, you could get an outdoor thermometer, and put the sensor inside the suspected area- to get readings until you know whether or not that area is a problem or not.

    Good Luck.
     
  7. Cosmic

    Cosmic Well-Known Member

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    As stated your core problem is probably a vacuum lock that occurs if the ice cap is solid against the sides. In gravity drain type systems that will result in little or no flow fairly quickly if no compensating air can get under the ice.

    Again a bubbler air system is the standard industrial solution to keeping a spot from freezing. I am not sure a fish tank type bubbler would provide enough air. Usually they are built with a metering tube that also allows for regulation of the amount of air. Might work here but I would try what may be a better solution.

    Your core solution is to get heat without electricity. The creek which will provide the hydro power can be that source depending on how the piping runs and elevations work out. Creek water under a frozen cap on the creek even in the coldest weather can be well above freezing. The Earth temperature is constant at ~48 F. Example if you measure most spring water it is about 48 F.

    Tap off some deep creek water, build a piping system, bury it as deep as possible, route to a heating coil in the cistern, let that be your heat source. Can also use as a heat source to protect your other piping. The creek water might be say 37 - 39 F but if it travels a distance underground deep enough it will actually pick up heat from the Earth and can be close to 48 F when it enters the heating coil in the cistern. No contamination can occur because the creek water is in a closed system.

    Any flowing water source can work, spring water, creek water, what have you as long as the flows, elevations, etc are suitable. Once installed is a fairly set /forget type system, needs little maintenance.

    Couple this solution with adding a floating foam cover directly on the cistern water level with say a 1/4 gap around the edge. Something like that blue building foam. Also add whatever insulation to the top cover that can be done. Think that should give a fairly bullet proof solution. You are using Mother Nature, not trying to fight her in any manner. You also need a return point for your heating water that is freeze proof. Can be back in the creek in a wet well affair that you build well under the surface / gravel bed. The prime principle is get enough head to ensure adequate flows thru the heating system. Take your flows under a gravel intake to prevent sucking up stuff that will plug the system.
     
  8. HydroMan

    HydroMan Member

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    Thanks for all the quick and thoughtful responses.

    I should have mentioned that I did break a big hole in the ice and left the cistern cover off and still did not get any more pressure at the house. Had a little water with the 12V booster pump running and no water when it was turned off. Of course the pump would not shutdown automatically because it was not able to build enough pressure. The only other conclusion is there must be some ice in the cistern outlet valve or pipe upstream from the house. Just bugs me because is buried 4 ft deep.

    Cosmic I like your suggested system, however I dont think it will work in my situation with out additional pumps. The highest part of the creek is still 20 feet below the level of the cistern and 150 feet distance. The creek is going to work great for hydropower, but not as a source of drinking or recirculating "heating" water.

    I am going to Cosmic's suggestion to cut a peice of that blue insulation board and and float it on top of the water in the cistern. My only concern is whether or not it will leach any chemicals into the water.
     
  9. Cosmic

    Cosmic Well-Known Member

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    You can still get that system to work by building a hydraulic ram type pumping system in the creek and pumping back a far smaller flow to get over your head difference. Same principle as filling a tank from a flowing source with a large elevation difference, using the flowing source as the motive power. May be talking a fair amount of piping but is simple in design. In a way the more deep underground piping in the heating system prior to the cistern the better.

    The beauty of that system is you will be able to heat trace your entire system, cistern, interconnecting piping, valving and use points. Nothing else will probably give the same benefits without introducing their own problem sets.

    If worried about the foam, seal it in a heavy plastic bag or something similar to encapsulate it.

    The P.S.

    Being 4 feet deep might not be deep enough for a water system in a colder environment. Maybe six feet or even eight would be more appropriate. Four feet might work if it is a working periodic flowing system. I take it the system is static for most of the freezing period. Deeper is better. Six feet is used in Boston for most water lines. 4 feet is really the outer limit normally considered for frost action.
     
  10. BackwoodsIdaho

    BackwoodsIdaho Well-Known Member

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    I can guarantee your pipes didn't freeze up! We live in an all solar off grid home in North Idaho (around Priest Lake) with a cistern and slow well pump setup. Our pipes are 36" below grade wrapped in foam insulation and we have never frozen up even with the 22 below we experienced last week and the other 20+ below spells in early winters. At 4' you are more than deep enough. Most people don't even go much below 2' up here because the high depth of snow of most years insulates enough.

    Our set up is the following. We use a Shurflo pump at the 60' level in the well casing. It is on a float switch in the cistern so the cistern is kept full by the float switch turning on and off. The cistern is a poly tank with about a 1200 gallon capacity. We then run the water to a dankoff 12V pump and a captive air tank for household pressure. The pump and captive air tank are in a buried vault outside the pump house in the front yard since we don't have a basement or space inside for it. The cistern has a small house built over it and is covered with insulation.

    My bet is that your pump may have a problem, esp. if it was allowed to run dry for any length of time. I know Dankoff's are very suspectible to running dry or dirt in the line. The vacuum idea is probably not it because you could break the vacuum with the line in from your well even if the ice did make a perfect seal. I would also check to make sure there isn't an obstruction some where in the line.

    my $0.02 worth

    PS Boston water lines at 6 feet - LOL - most of them are clay anyway from god knows how far back. The biggest water line there is the central artery replacement tunnel LOL. I am glad I left that hell hole once I finished graduate school.
     
  11. Cosmic

    Cosmic Well-Known Member

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    Think somehow you got your lines crossed.

    All the water lines are cast iron, just about always have been. Just replaced all the ones around me, the old ones where cast iron, replaced with new cast iron. Many sewer lines are clay fired sewer pipes, some older ones maybe brick. The sewer lines are at 8 feet, the water mains at 6 feet over top them. The service relays and inlet lines still have many lead lines, replaced with copper. They really are at 6 feet, come right into the basement that way. Boston unlike many cities never seemed to be a fan of any form of cement lines for water.

    http://www.pubs.asce.org/ceonline/0799feat.html

    Maybe wood in the very old days, no clay. I should not be around that much longer to keep you up to date on the plumbing. :D
     
  12. HydroMan

    HydroMan Member

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    Hi Backwoods,

    I am located up in the Rapid Lightning Creek area about 13 mile NE of Sandpoint. Steve Willey is a neighbor about 1/2 mile up the road from me.

    Anyway, you and I have a similar set-up. The only real difference is your booster pump and pressure tank are in a buried vault and mine is a below grade crawl space. The space is about 3 feet wide by 4 feet deep horizontally and about 4 feet below grade measured from the floor to the ceiling. About 6 inches of dirt on top over a log ceiling structure. The big weak spot is the uninsulated plywood access door where I walk in stooped over. I would like to find a way to insulate this space better.

    I dont think the booster pump is bad. It is a Shurflo model 2088 and is supposed to be able to run dry with no harm. Also, I am getting just a tiny trickle of water coming through the gate valve when disconnected from the inlet side of the pump. If there was not a problem upstream from the pump and it was the pump that was bad, I would expect a pretty steady low pressure stream of water coming out of the open valve. You may be right about some obstruction in the line that may not be ice. I just hope it is not somewhere in the 40 feet of 4 foot deep buried pipe coming from the cistern to the house.

    Are you saying you have never had a problem with the water in your cistern freezing? I am surprised that simply insulating the shed would keep it from freezing in subzero temps outside. Tell me a little more about your insulated cistern shed set-up. What type of insulation and where is it insulated? How big is your shed?

    Thanks,
    Dave
     
  13. HydroMan

    HydroMan Member

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    Cosmic,

    Just realized that I may have a problem implementing your idea of placing a peice of blueboard insulation on top of the water in the cistern. The circumference of the cistern is about 6 inches greater to the outside edge of the cistern then the access hole. I guess I could split it into 2 peices but that may leave a gap in the middle as it floats it floats around in the water, particularly with a 1/2 inch gap from the cistern walls. Am I missing something.

    In addition to insulating the cistern shed walls, I am thinking of laying a couple layers of radiant insulation blanket over the top of the cistern cover.
     
  14. Cosmic

    Cosmic Well-Known Member

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    Hydroman

    Nope, you got it, lots of ways to skin the same goat.

    One way is make the cover in 1/2's or 1/4's and when you encapulate it, hinge the sections so it can fold for installation. When deployed it will form a full intergal circle. Little extra protection never hurts. Lot of tanks in industry use floating covers of some type for a variety of purposes.

    You might want to try to run an electricians snake down the water line if possible to see it is plugged by something. If not, maybe can back blow it.

    Another idea that maybe can be used in some manner is how to produce compressed air with no electricity or moving parts. Can get around the elevation difference you mention before. Maybe even useful in a shop or power plant scheme in the future. Was used way back when before electrical systems became common to power systems via air.

    Probably can't use the air directly in the cistern because it would probably be considered contaminated by direct contact with the creek water but could either generate heat with it or power something or figure out a way to use it as the heat transfer fluid in a heating coil as some more insurance.

    http://www.motherearthnews.com/arc/4300/

    Somewhere I think there is another article by Mother Earth News that gives more of the sizing, construction details and design data. Am in a mess because I am packing up my tech library. Also there is a very detailed nomograph that has the sizing data floating around. Mind is drawing a blank as to who / what to search for it. Maybe in Peale's Mining Handbooks. (I can check) Very detailed descriptions and pictures in some books about a very early system in Paris. Nothing like having a shop air system that is oil free and doesn't need power or a compressor.
     
  15. Steve

    Steve Well-Known Member

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    Hydroman,

    For what it's worth, review my reply post from a previous winter.
     
  16. BackwoodsIdaho

    BackwoodsIdaho Well-Known Member

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    Hey Dave - have driven many times right by your place up to Steve's to get various solar or other alternative energy parts. Now I guess they have moved a bit closer into Sandpoint at the convenience store now. You have a really nice spot up there.

    I used to work in Sandpoint at Coldwater Creek but now I just do freelance programming and consulting mostly from home.

    Anyway, on to the cistern. We purchased a Norwesco poly cistern from RC Wurst in Couer d'alene. I buried it about 25 feet from our cabin and 20 feet or so from our well. The top 6" or so of the inspection covers are out of the ground. The piping into the cistern from the well is 1" poly line that comes into the top of the cistern and then makes a 90 elbow to a 4' or so piece of pipe that delivers the water to the bottom of the tank. I did this because I was afraid if I ever developed a leak where the fitting was on the cistern, I wanted it above the water level so that the tank didn't empty itself and float up on the leaking water. I also like this setup because it keeps the water li turning over in the cistern and the sediment (if any) can precipitate out of the water. The supply line to the dankoff pump is also a 4' or so pipe to the lower part of the cistern up to a 90 elbow at the top and out to the pump with a check valve inline to keep the pump always primed. The dankoff pump sits bolted on top of a horizontal captive air tank that provides the water pressure to the house supply via a 3/4 inch line.

    The cistern has a small house basically the same size as the footprint of the cistern built around it with a shed roof. The tank is covered with a 6mil plastic vapor barrier, then I used the foil insulation with air bubbles inside. I saw this used in a yurt for insulation. I duck taped these sheets together to make one big space blanket. Then I took conventional fiberglass insulation and wrapped it in plastic to keep it dry and put that over it, then I covered the whole melange of insulation is another sheet of 6mil black plastic. The shed is built of cedar horizontal siding left over from our cabin and dark green metal roof.

    So far, we have had no water problems at all. The best part is the water is clear and cold in August. I can email you a picture of our setup if you like.

    jim
     
  17. edjewcollins

    edjewcollins Well-Known Member

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    Can you blow the system back to the cistern to see if that helps? Not enough air pressure to damage anything just see if the line is fouled.

    Ed
     
  18. Cosmic

    Cosmic Well-Known Member

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    Might want to rethink the entire problem.

    Seems to be two systems built something identical. One freezes, the other doesn't. Difference I would reckon could be more in the hooch that covers the cistern than anything else.

    I have two sheds just about equal in size. One on pier blocks, wood floor, one with poured concrete floor, long back wall layed up stonework, totally Earth sheltered by being buried within about 18" of the top. Difference on a winter day is incredible. Can just about store something in the Earth sheltered one without it freezing if tucked in toward back wall. Back to that old Earth temperature being ~48 F at depth.

    The solution might be totally rethink the hooch over the cistern. Masonry totally Earth sheltered except for a door opening. I also remember all the old farm milkhouses, spring houses, etc as a kid, none I ever knew froze in winter. All were designed to be Earth sheltered. Just that amount of heat is enough to overcome the Heat of Fusion which is the extra amount of energy that must be lost after water reaches 32 F before it turns to ice. Talking ~142 BTU's / Lb.

    A floating cover is good, an insulated cover is good. Think burying the hooch here is the key. Or if it doesn't have a true hooch over it, building one.
     
  19. HydroMan

    HydroMan Member

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    Cosmic,

    Hooch?...Sorry, but the only hooch I know of comes in a bottle insulated by a brown paper bag. Please explain.

    The shed over my cistern is about 6x6 with an open gable ceiling which is about 8 ft at the peak. The floor is 6 inches of concrete with the top about an inch above grade. The concrete cistern access cover is in the center. Construction is 2x6. Siding is T111 painted brown. Metal blue roof. Interior is uninsulated.

    What you decribe is an earth berm structure. Not sure this could be accomplished without tearing down shed and building up some type of stone structure and moving some earth. Right now I planning to just insulate the hell out of the shed and the cistern cover and see what happens from there. I think I will use that radiant insulation blankets rather then fiberglass batting. Then if needed go with some of the more "exotic solutions"

    Your description of an underground shed with only an access door opening sounds close to what I have sheltering my booster pump, 1 gallon air bladder pressure tank and valves. This is located just outside the perimeter of the house. I still think there is too much cold air getting in there too (through the thin layer of earth on top and through the plywood access door., but I have not had a freeze probem yet that I am aware of. But a I did replace one valve that I broke in 2 when I went to open it right after buying the place. My guess is that it had froze last winter and the previous owner never bothered to fix it. The place was built in 1999.

    Like I said earlier I would have designed the whole plumbing system differently if I was starting out fresh. As is typical up in North Idaho, things tend to be cobbled together as money allows.

    Sure appreciate everyones help. Got a whole bunch of ideas to try out. I hope to give everyone some real world feedback after my next visit next weekend or the one following.

    Thanks,
    Dave
     
  20. HydroMan

    HydroMan Member

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    so far, we have had no water problems at all. The best part is the water is clear and cold in August. I can email you a picture of our setup if you like.

    jim[/QUOTE]

    Jim,

    Go ahead and send me your pics if it is not too much trouble. I think you can email through this site. Rather not post my email address here due to spammers.

    I will try to take picture of my set up next time I am up there and then post here to give everyone a better idea of what I am talking about, although I think everyone has a pretty good idea.

    By the way the link to your misty ranch website does not appear to work. Maybe you and I can hook up sometime. I live in Libery Lake during the week.

    Thanks,
    Dave