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Thread: Simer water pressure booster pump

  1. #11
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    Re: Simer water pressure booster pump

    Egon, Easier said than done. There may be a periodicity or repeatable sequence but I haven't figured it out yet if it exists. It isn't like in large cities where the water pressure fluctuates in time with TV commercials from all the folks waiting till commercial to go to the bathroom.

    It may be something like a random sequence where when the cylindrical water storage tank/tower gets to its lower set point and a pump fills it to the top set point. This would give varying pressure due to the head but not related to consumption in a simple manner. The highest and lowest pressures would not follow a schedule. How often the fluctuations occured would be a function of average usage but peak usage might happen at peak pressure.

    [img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
    "I'm not from your planet, monkey boy!"

  2. #12
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    Re: Simer water pressure booster pump

    Pat, the pressure is the pressure and there are only two of them; static and dynamic - standing still and moving. No matter the volume of the tank, pressure is pressure and it won't increase because of a larger tank being installed. Plus, your problem is lack of pressure and flow. So putting a big bulge (a tank) in the plumbing ins't going to get more pressure or flow; just a larger volume of low pressure slow/low flow water. The capative air precharge pressure isn't going to increase pressure, it equalizes to your main line water pressure when you shut off the shower.

    Your pressure (to the tank) is controlled by the pressure switch settings you have the well pump pressure switch set for, or whatever the city pressure is at your house. Since you want to boost pressure, IIRC, you have city water, a pressure tank is not going to increase your pressure (even if you had a well); or prevent pressure fluctuation.

    You need a booster pump but, if the pump wants more water than the city supplies, you must go with an atmospheric storage tank to provide flooded suction (more volume) to the pump or it won't solve your problem while it causes another problem; cavitation damage of the pump, along with less money in your wallet.

    The best choice for a pump is a correctly sized for your house shallow well single line/jet pump. They require a pressure tank. That setup, either a pressure tank or atmospheric tank and pump, will come with a corresponding pressure fluctuation. The only solution is a variable speed pump or CSV or Smart Tee (uses a type of CSV not as good as a CSV).

    A CSV will prevent the pressure fluctuation in your house. Although I have them available to me, I do not sell them but Bob does. I turned him on to them... I know Bob, and he may, if you talk nice to him, guarantee no noticeable fluctuation in water pressure past the CSV. I could sell you one with that guarantee... but I prefer not to sell pumps, tanks etc. and concentrate solely on water treatment; which usually has me overworked without taking on more.

    CSVs cost way less than variable speed pumps and their controllers and don't require anything other than simple plumbing to install one in your plumbing. And to go variable speed, you then must use an atmospheric type tank which opens the door to water quality issues and increased maintenance to deal with them and equipment in some cases. Which all equates to more money to simply be able to power wash yer butt in the shower.... [img]/forums/images/icons/wink.gif[/img]

    Gary Slusser
    Quality Water Associates

  3. #13
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    Re: Simer water pressure booster pump

    Gary, Thanks for the very informative post. I understand everything you said, in detail, except the fine nuances relating to CSV smart T stuff. I can research that.

    It isn't that I don't understand the way air backed tanks work that caused me to say what you didn't agree with. I gave a very narrowly defined example that youi may claim is not often encountered. I stick by my earlier comments.

    If there is a time varying pressure applied to a bladder tank through a check valve the tank will tend to pressure up to the highest pressure in the varying pressure profile, NOT the average or any other pressure but the peak which might be significantly higher than the typical pressure. This is the part yoiu disagreed with but it is sound science. Perhaps it has little or no practical application but is true.

    I do thank you for your post, I will look into thte parts with abbreviatioins that I don't understand.

    [img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
    "I'm not from your planet, monkey boy!"

  4. #14
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    Re: Simer water pressure booster pump

    [img]/forums/images/icons/tongue.gif[/img] Pat, you are actually considering a very small increase in pressure here. The difference between the shower stream hitting the twelfth tile and the eighth tile on the wall is only about ten pounds of pressure. Most hydro-boost setups are made to add a lot more than just ten PSI, so a packaged unit might actually be a waste of money compared to a tank, a check valve, and a switch. Whether you buy a "smart valve" or not, the storage is the key. It'll help with the inertia thing and reduce cycling. A single-stage, end suction centrifugal would be a good choice. They also make some nice stand up units with straight-line piping Check Sta-Rite, PACO, and Goulds. It would be nice to go 1750 RPM for longivity, but at the low flow it may be difficult to find one. 1750 RPM would have a way better chance to overcome the low NPSH on the intake side and would have a reduced tendency to cavitate on startup. [img]/forums/images/icons/tongue.gif[/img]
    CJDave

  5. #15
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    Re: Simer water pressure booster pump

    The control on the Simer booster pump you are looking at works by starting the pump at a low pressure and stopping the pump a few seconds after the flow has stopped or almost stopped. Some of these devices have a small bladder to store only a spoon full of water. Unlike electricity it takes a second to get the water moving in the pipe. Open a tap, low pressure starts the pump. A second later the pump surges water to the open tap then pressure increases. The biggest problem with these type controls is a leak in the system. The flow switch in these controls usually shuts the pump off if less than 1/5 of a GPM is being used. Then because there is no bladder storage tank, the pressure quickly drops and the pump restarts. A dripping faucet or running toilet can cause the pump to cycle about every eight seconds until something burns up. A Cycle Stop Valve works with a bladder tank. It allows the stored water from any size tank to be used for instantaneous demands without any surging. It allows a dripping faucet to draw from the tank for hours, depending on the tank size. Then the CSV keeps the pump from cycling while using small demands like a single shower or single hose.

    Another problem you may have is with the water supply. If the pressure is already as low as 20 PSI sometimes, it stands to reason that it will be even lower when your pump starts sucking on the city supply. As long as your pump is large enough to boost from 0 PSI to the pressure you require, no problem. If the pump sucks the city pressure below 0 PSI you could cause lines on the suction to collapse. Then it would be better to let the city fill a storage tank and have the pump draw from the storage instead of the city line.

  6. #16
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    Re: Simer water pressure booster pump

    [img]/forums/images/icons/tongue.gif[/img] How about doing a flow test, Pat, and just see what kind of maximum delivery the supply line is capable of. By doing that, you could assure yourself that you aren't battling a flattened pipeline, or a partially closed valve. By ascertaining the flow available, even at near zero head, you can make a more intelligent guess as to the correct size of the booster system. You can try the test at various times during the 24-hr cycle and thereby find the worst case scenario that can then be used as the pumping plant design criteria. I'm looking across the room at an enlarged photo of a line booster station that I built a few years ago and which might be just what you need. The photo shows three, 75 HP split-case double-suction Peerless centrifugals pumping in parallel.....oops....that may be a bit oversized for your deal.....but it does make a nice picture. [img]/forums/images/icons/smile.gif[/img]
    CJDave

  7. #17
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    Re: Simer water pressure booster pump

    Dave, I have measured my pressure under 20psi at times and would like at least 40 and 45-50-55 somewhere in there would be great unless someone explains why that would be bad.

    The increased pressure in a storage tank (pretty much the peak pressure experienced over the time window in question) with a check valve on the input under a varying supply pressure is NOT a practical means of boosting pressure unless yoiu had an enourmous bladder tank like the size of the house or only needed a few pints of water. I was just waxing theoretical. Sorry, my feet are approaching terra firma even as I write this.

    I realize shower trajectory geometry is not a very well calibrated pressure measurement when it comes to communicating. Lets just say it goes under 20 psi and up to about 30-40 and I would like 40-50. This means with a shallow well pump it wouldn't have to pump a lot every time I drew water, mostly when pressure dipped.

    I'll rely on you professionals to steer me regarding cavitation and other fine points of system design where I have little to no experience. I do know cavitatioin is a BAD thing and erodes metal parts and makes a lot of noise. I actually had to study cavitation a few times. Once at the Anti-Submarine Warfare School in San Diego.

    Comment en passant cavitation: When you pop your knuckles you are forming cavitation bubbles and the snaping sound is the bubbles collapsing in on them selves as pressures are equalized.

    I'll check out your recommendations re brands and RPM etc. It isn't like this is a crisis, we are doing OK in all aspects of water delivery except outdoor watering where watering times are highly variable and my automatic system runs on time not volume. ...A N D shower pressure varies buy a factor of two or more. Other things are level controlled: dishwasher, clothes washer... so pressure isn't a big deal.

    My reaction may be slightly out of proportion but pressure under 20 psi bugs me.

    1994, Thanks for chiming in.

    ...and Dave, you are absolutely right about my needing to do some flow rate experiments. Pressure measurements before and after timed filling of a 6 gal bucket repeated whenever the static pressure is at a value of interest that hasn't been done yet will give some design data.

    I am fairly confident but not entirely sure that I don't have untoward flow restriction losses in the house plumbing but will do the timed flow thingy from both ends of the house, both close to and away from the supply entry point. Probably do a particular outside frost free hydrant too as it gets water in parallel to but not through the house.

    I have over a 1/4 mile run of 2 inch slip together (not glued) PVC pipe coming from a 6 inch line running from the treatment plant to the nearest town (couple miles past me.) The 6 inch run before it gets to the 2 inch connection is about 6 miles. The meter is about 600 ft or so before the 2 inch terminates at the house and becomes 3/4 inch. The meter is 3/4 inch in and out so it is a restrictive orifice. It is downhill to me from the 6 inch. A head of about 20-30 feet.There is just one elbow in the run and that is just prior to the meter. IT is on the rural water district's side of the meter, out of my sphere of influence.

    [img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
    "I'm not from your planet, monkey boy!"

  8. #18
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    Re: Simer water pressure booster pump


    Now I'm really getting confused. [img]/forums/images/icons/confused.gif[/img]

    If the supply is lacking in volume the outdoor sprinker system isn't gonna work no matter what you do unless there is a very large storage tank.

    Surely the shower unit will not require enough water to deplete the public water main?

    Why not just install a small manually switched inline pump downstream of comingled hot/cold water for the shower head?

    Or use a bathtub?

    Egon [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]

  9. #19
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    Re: Simer water pressure booster pump

    [img]/forums/images/icons/tongue.gif[/img] I don't believe that this application calls for a shallow well jet pump. A single-stage centrifugal will work just fine and will give you the boost that you need; there doesn't seem to be any justification for adding a jet. The supply line SEEMS like it is big enough, especially if you gain some static head from the water main to your point of use. That 3/4" meter should not be a problem or a significant restriction for normal domestic water system flows. Water supply agencies often frown [img]/forums/images/icons/mad.gif[/img] on customer installed booster systems, but the reality is that many areas served by "rural water" are horribly low on pressure. [img]/forums/images/icons/frown.gif[/img] You could also try crabbing about your feeble pressure to the guys at the water works. If you do mention it, however, don't say the word: "booster". just act resigned when they tell you that: "You have a froobled framis out there and it's a special case, and nothing can be done". [img]/forums/images/icons/smirk.gif[/img]
    CJDave

  10. #20
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    Re: Simer water pressure booster pump

    I'm for the flow test CJDave mentioned.

    I'm not for the centrifugal over the jet though. The jet will pull plenty of water for his needs in the shower and do a great job of boosting if more water is available, which I agree should be. But I think a centrifugal would try to draw too much water which would make any possible cavitation worse than would the jet pump.

    I didn't know Pat had a sprinkler system. If so, how good does it work and what flow does it require. That would answer a big question.

    bob...

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