UV light, well tanks and power outages

Discussion in 'Pumps and Tanks Well Forum & Blog' started by cnrhome, Feb 11, 2008.

  1. cnrhome

    cnrhome New Member

    Messages:
    9
    Location:
    Hudson Valley, NY
    Hi all,

    I have a bunch of questions about my water system, but I'll start simple. Heres some info :

    80 ft well, submersible pump, 100 ft uphill to house
    Pressure tank is Duracell Blue DP-42-2. 18" diameter x 36" tall. ( I'm guessing 42gal ) Air bladder charged to 38 lbs
    40/60 well pressure switch
    4 bdrm, 2.5 bath house. 2 full baths on 2nd floor
    Full height basement with plumbing equipt on floor
    Water filter/softener
    7 gpm rated UV light

    The UV light was put in 8 yrs ago when we bought the house - coloform was found. I need to replumb my system for various reasons and want to do it right. My issues are :

    - We lose power here and its annoying. Without the UV light, we could use the tank drawdown to have some water without electricity. However, with the UV light and no power, we cant use a single drop as it would contaminate the house.

    - I think the drawdown on the tank is about 5 or 7 gals? Not much. Its my understanding that its more wear/tear on a wellpump to come on frequently. So I'm wondering if my pressure tank is a bit undersized.

    My attempt at a solution is to add another pressure tank (roughly the same size) AFTER the UV light. This would give me double the drawdown, save my pump and (with an appropriately placed valve) I could shut off the 'contaminated' system and use this second tank to give me some clean water to use during power outages. I'd probably have to build a shelf to put the second tank above the first tank, as floor space is at a premium.

    I know it would be weird and uncommon, but does this sound reasonable? I've done much more complicated things, so doing the work is no problem. What do you think? I'd appreciate any other ideas or suggestions.

    Thanks!

    CJ
  2. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    A Cycle Stop Valve would save your pump from cycling. If your looking for storage I recommend a galvanized or similar tank that you can add air too when needed. This will give you much more storage than a bladder tank and you will get water down to 5 psi or so where the bladder tank will be empty at two lbs. below the cut in pressure of the pump. I have a CSV and a small 42 gallon Bladder Tank then after the Bladder Tank, I have a 120 gallon galvanized tank that has an air pump which not only keeps it topped off with air, it gets rid of my Sulphur Odor. It's actually my Sulphur Removal System. With the Hurricanes we had a few years back, I didn't need to start the pump too often with the bigger tank.

    bob...
  3. Gary Slusser

    Gary Slusser That's all folks!

    Storing water after treatment with a UV light is a bad thing.

    Plus you don't get twice the drawdown because you have to shut off the water from the first tank or you get raw water from it through the powerless UV light into the second tank.

    Not to derail your desire for a new project... ;) if you want some water, usually for flushing toilets, a couple 5 gallon buckets with sealed tops and stacked to save floor space where you'd install this new pressurized tank is a much better solution and only costs $10 maybe (at Wal-Mart).

    A few $.25-$.75 per gallon gallons of bottled water for coffee and drinking water and brushing teeth takes care of water to be ingested and takes up little space if stacked on top of a board on the stacked 5 gallon buckets.
  4. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    Depending on how often your power goes off you might want to put in a generator. With careful managing of loads a 5 to 7.5 kw generator can power your pump, refrigerator, furnace, a few light and some cooking (not all at the same time). I have one hooked up to my main panel with a breaker that is interlocked with the main breaker, which is better than the 6-circuit transfer switches because it provides access to any circuit in the house.

    Since I'm in New England where we use oil heat I got a 5.5 kw diesel so I have plenty of fuel on hand. The whole thing cost less than $1000 with DIY setup.
  5. cnrhome

    cnrhome New Member

    Messages:
    9
    Location:
    Hudson Valley, NY
    Hey guys... Thanks for the responses...

    Speed - how does a CSV stop my pump from cycling? If the tank only has 5-7g of drawdown, the pump will run, no matter if the pressure to the faucets is constant or not. Am I misreading what a CSV does?

    Gary - Normally (with power) I would get twice the drawdown. Its only without power that I'd get half, which is more than the zero that I have now. Whats the reason you said storing UV'd water isnt good? Would it really be 'stored' - isn't it used and refilled with every pump cycle? Yeah, I have the lo-tech solution (plastic bottles) which I have used, but my 2 small kids don't understand not to use water when Daddy says so. :)

    Bob - I've thought about a generator, but ONLY $1000 total - for the unit and the DIY install? How did you pull that off? I looked into it once and don't you need something to ensure the generator doesn't put power back up to the power lines? I thought that was a transfer cutoff switch which costs a few hundred $, and would require an electrician and/or power company. Then I need a place/slab for it and cover so the weather doesnt beat it and storing fuel. Seems like a bigger project than I want to do now. Power goes out enough to be annoying, but not enough to get me into Fix-It mode. :)

    Thanks for your input...
  6. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    I bought a 5.5 kW Kipor electric-start diesel generator on Craig's List for $750. I bought a QO interlock kit for my panel on e b a y item # 290196653647 for $78.50 including shipping. That's $828.50. I used some wire that I had and a $20 disconnect from HD to connect the generator to the panel. The total is less than $1000 if you have to buy any other stuff.

    I chose diesel because I have a tank of fuel oil to heat the house. You can probably buy a 5 to 7 kW gas generator at Sam's Club or someplace for $500 to $600. I keep the generator in my heated garage and wheel it out when necessary so it starts reliably.

    The interlock is better than a transfer switch because it lets me use any circuit in the house as long as I manage the load (Turn off the electric water heater and don't use the electric range or electric dryer). I can run my computer and have internet access because the cable company has power backup. I was able to run a 14,400 BTU A/C and start a 1 HP motor on my table saw at the same time, and the generator handled it easily.

    I connected my generator to deliver the whole 5500 Watts at 120 Volts because I have city water with no pump. That makes it a little easier to manage the load.

    What a CSV does:
    A CSV is a pressure regulator with an internal bypass that bypasses about 1 GPM when the regulator is closed. Suppose you have a tank set at 40/60 psi with the pressure switch and a CSV set at 50 psi. Your pressure switch operates normally until the pressure drops to 40 psi and when the pump comes on until it reaches 50 psi. Then the regulator feature of the CSV throttles the flow to keep the pressure at 50 psi as long as you are using 1 GPM or more. If you are taking a 15 minute shower the pump stays on the whole time. When the water is shut off the internal bypass of the CSV allows about 1 GPM (more or less) to pass through to raise the pressure in the tank to the 60 psi shutoff so the switch eventually shuts off. After the pump has shut off the system operates like a standard system until the pressure drops to 40 psi, starts the pump, and the pump raises the pressure to the regulated pressure of 50 psi, when the CSV takes over again.
    Last edited by a moderator: Feb 12, 2008
  7. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    I got my 5KW portable Generator for $400 at HD. I think it was $600 normally. And that's with a "10HP" Subaru engine. (I test small engines for a living, Subarus have done very well)

    I just keep some fuel on hand. If I don't use it within a month or 2, I drain it into my car and refill the gas can to keep the gas fresh. I'd rather do that then the costs of an automatic backup generator.

    And I'll be installing an interlock switch as well with an outside receptacle to bring power in soon.

    5KW would allow me to do whatever I wanted to do as long as I was careful. But my Stove, Dryer and WH are all gas, so that helps.
  8. cnrhome

    cnrhome New Member

    Messages:
    9
    Location:
    Hudson Valley, NY
    Hey - great info! So the 'interlock' is like a double pole breaker that feeds the panel from the generator? What size wire did you need to carry that load? And the cutoff goes on your main line to cut the house from the street, right? Did that take an electrician to install? I also use oil so all I need is a valve on my tank to get some into a can. I guess it takes just a few manual steps to get power going.

    Very interesting! I always wondered why a separate generator panel was used and circuits rerouted. I figured it should power the whole panel and just be smart about what elect was used!

    I know this isnt an elect forum so thx to the Mod for indulging me...

    And thx for the CSV info. It just clicked in my head when reading that since it keeps the pressure at 50 while water is used, the pump wouldnt turn off. I dont know how pumps work, but would the pump 'overtake' the water being used? Since it can pump more than the 2.5 gpm shower can take, wouldnt the pressure rise in the tank to the 60lb cutoff pressure anyway? I guess this is a great device if you have steady water usage that would normally cycle the pump 3 or 4 times. Do dishwashers and (front loader) washing machines use enough steady water (like showers) to make this device worth installing?

    CJ
  9. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    So the 'interlock' is like a double pole breaker that feeds the panel from the generator?

    No. The interlock device is a mechanical device that prevents the handle of the standard double-pole generator breaker from being turned on when the handle of the main breaker is in the ON position. The backfed breaker for the generator is installed in the top position of the right column for a Square D QO panel. It may be different for other panels.

    What size wire did you need to carry that load? And the cutoff goes on your main line to cut the house from the street, right? Did that take an electrician to install? I also use oil so all I need is a valve on my tank to get some into a can. I guess it takes just a few manual steps to get power going.

    The wire size must be large enough to carry the full current of your generator, such as #10 for 30 Amps. I used #6 because I had some but that is larger than I need for my generator.

    The main breaker remains your cutoff to the power company. The INTERLOCK merely ensure that the main breaker and the generator breaker are never on at the same time.

    It did not take an electrician to install but it did require working inside the panel. I had to drill some holes in the panel cover to mount the interlock kit.

    I just siphoned oil from my tank into a 5-gallon plastic fuel can. Don't mistake gasoline and fuel oil if you have fuel oil in a can for the generator.

    The manual steps are:
    1. Start the generator and connect it to the system so it is warmed up and ready to handle load.
    2. Turn off the main breaker.
    3. Turn off breakers to loads that would overload the generator, such as electric dryer and water heater, oven, and stove.
    4. Move the interlock to permit the generator breaker to be turned on and turn on the breaker.

    I dont know how pumps work, but would the pump 'overtake' the water being used? Since it can pump more than the 2.5 gpm shower can take, wouldnt the pressure rise in the tank to the 60lb cutoff pressure anyway?

    When the pressure rises a little above 50 psi the regulator closes. Then the only flow is through the 1 GPM bypass. If the demand is greater than 1 GPM then the regulator operates to keep the pressure constant. If the demand is less than 1 GPM then the pressure will eventually rise to 60 psi and the pump will shut off.

    I guess this is a great device if you have steady water usage that would normally cycle the pump 3 or 4 times. Do dishwashers and (front loader) washing machines use enough steady water (like showers) to make this device worth installing?

    Diswashers, washing machines, toilets, and lavatory faucets that have successive demands on the system will cause the pump to run whenever there is enough demand to drop the pressure to the START pressure. The CSV doesn't do anything except in that portion of the cycle WHEN THE PUMP IS RUNNING AND THE PRESSURE IS BETWEEN THE REGULATED PRESSURE AND THE SHUTOFF PRESSURE OF THE SWITCH. At all other times it acts as if the CSV doesn't exist.

    If the tank is small, then each flush of the toilet might cause the pump to start. If the tank has enough drawdown capacity for several flushes then it will start less often.
  10. valveman

    valveman Moderator Staff Member

    Messages:
    4,369
    Location:
    Lubbock, Texas
  11. Gary Slusser

    Gary Slusser That's all folks!

    UV does not kill bacteria. It effects their DNA and that prevents reproduction.

    In this case stored means usable and treated water remaining longer than normal use would normally allow it to.

    The water stored in the plumbing after the UV light say overnight, is but 2-3 gallons at most but it is flushed out of the plumbing every time water is used. To go to a large tank now with maybe 12 or more gallons draw down, and especially during a power outage where water conservation is paramount, there will likely be many gallons of water stored in the tank for many hours to x days possibly. And that's with young kids that don't listen about not using water... and more susceptible to bad water than adults, and we're going to provide them more water to use.

    How long does the power stay off? IMO, more than 5-6 hours is too long, and for everyday use when the power doesn't go off, a pressure tank never fully empties before the pump comes on. So there would always be some stagnant water in the tank until you used it during a power outage.
  12. cnrhome

    cnrhome New Member

    Messages:
    9
    Location:
    Hudson Valley, NY
    Bob - Thanks for your explanation of the interlock. Makes sense now. You first mentioned a $20 'disconnect' in addition to the interlock. What is that? And the CSV sounds interesting. I'll do some testing on my current drawdown of the tank to get an idea if it'll be worthwhile. Where does a CSV go in the plumbing? My understanding is well->checkvalve->40/60 pressure switch->tank. Does the CSV go after that? How susceptible is a CSV to iron/sediment damage or clogging?

    Valveman - thanks for the additional detail

    Gary - "UV does not kill bacteria. It effects their DNA and that prevents reproduction. In this case stored means usable and treated water remaining longer than normal use would normally allow it to."

    Do you mean a longer holding time allows bacteria to reproduce? That would be bad :( I wasn't thinking of a large second tank, just another small one, with 4 or 5 gallon drawdown. Power outages aren't that long, usually 2-4 hrs. But I guess theres always some water left in the tank that gets constantly diluted with new water when the pump comes on.

    Thanks for the answers and I hope I'm not annoying everyone yet. I like learning about new things and how they work.:D

    CJ
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