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Thread: Replacing storage tanks with bigger submersible well pumps

  1. #1
    DIY Member luc's Avatar
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    Default Replacing storage tanks with bigger submersible well pumps

    Hello everyone.

    We are considering some changes on our domestic water system supplying our building and I would like to know your advise.

    We have two large concrete storage tanks in the basement of our building which are used to store the domestic water. The tanks are fed from two wells. When the building was first built, there were two booster pumps(Hydropak 6625 from Armstrong) that took the water from the tanks to supply the building. Each pump gaved about 50GPM@61PSI. This was so noisy that we put them on standby. The booster pumps only run during peak periods(it happens only a few times a year). We now supply the building from a submersible pump in each storage tanks. We do the rotation of the storage tanks. While one tank is being used to supply the building, the other tank is being filled by the well.

    The first well is 100' deep with 3000GPH. It has a 3/4 hp submersible pump of 15GPM@150' with a 11/4'' outlet.

    The second well is 200' deep with 1800GPH. It has a 3/4 hp submersible pump pf 10GPM@240' with a 11/4'' outlet.

    1) We would like to remove one of the storage tank. The other storage tank could be used for preheating of the water for the domestic hot water.

    2) We also would like to completely remove the booster pumps and supply the building directly from a new submersible pump in each well. There building occupency varies regularly from 30 to 56 persons. With 80 GPM available from the wells would this be enough to cover a peak period?

    3) We would like to keep a pressure of about 60 psi. Would two new submersible pumps(30GPM and 50GPM) be able to do this?

    4) We will also have to change the piping from the wells to the building and the electrical cables feeding the pumps.

    5) We already have two pressure thanks that were used for the submersible pumps in the storage tanks. We could use one pressure tank on each of the submersible pump system piping.

    6) We could also use a cycle stop valve on each of the pump system. If I am not mistaking, we can set the cycle and stop valves at different pressure to start the second submersible pump when the first one cannot supply the demand.

    Regards,
    Luc

  2. #2
    Moderator valveman's Avatar
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    You have a perfect application for a CSV. You need a CSV, a pressure tank, and a pressure switch for each pump. Set the pressure switch for the 50 GPM pump at 50/70, with the CSV set a to 60. Then set the pressure switch for the 30 GPM pump at 60/80, with the CSV set at 70 PSI. This way the 50 GPM pump will not come on as long as the 30 GPM can keep up with the demand but, it will come on and increase the flow to 80 GPM if needed.

    Without the CSV, even with an alternator or "duplexing relay", (witch I never liked) you would need a half dozen big pressure tanks, and the pumps would still cycle on and off all the time.

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    DIY Member luc's Avatar
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    Thanks valveman for your input.

    We still have to decide if we are going to place the valves and pressure tank for the wells inside or outside of the building. There might be a new building nearby and we would also like to supply the water to this building. Anyone know how many people can be supplied by 80GPM of water?

    Luc

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    Moderator valveman's Avatar
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    Office buildings are different than houses. Nothing but sinks and toilets usually. 80 GPM would flush about 30 or 40 toilets at exactly the same time. The odds of 40 toilets flushing at exactly the same time when there is only 100 people in the buildings would be rare. However, people do seem to take breaks at about the same time, so water use in buildings comes in spurts. Depends on the schedules but I would guess 80 GPM would supply more than 300 persons in an office building(s).

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    DIY Member luc's Avatar
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    Thanks Valveman.

    I forgot to mention that our building would be considered more like a motel or in the institutional category. In this case, it would probably be better to consider how many shower and/or toilets that can be used at the same time.
    With 2.5GPM showers, I would guess about 32??

    Luc
    Last edited by luc; 04-27-2009 at 06:09 AM.

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    Moderator valveman's Avatar
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    Quote Originally Posted by luc View Post
    With 2.5GPM showers, I would guess about 32??
    Luc
    Would that be 2.5 X 32 for 80 GPM, or 32 GPM total? Either way you are OK.

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    I'm not sure how you would use a CSV to do this, however a duplexing relay controlled by two separate pressure switches would do the trick, try Googling for duplexing relay.
    Hey Rancher,

    Are you still trying to sell those duplexing relays on e-bay? I would have thought you would have ran out by now.

    I see your still on your rant about Cycle Stop Valves too. You'll never learn John!

    bob...

  8. #8
    DIY Member luc's Avatar
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    Quote Originally Posted by valveman View Post
    Would that be 2.5 X 32 for 80 GPM, or 32 GPM total? Either way you are OK.
    Sorry, that was 2.5 x 32 for 80GPM. I know that this would be plenty of water to accommodate the 56 persons in the present building. But, I would like to know for our new building. With your experience, can we cover up to 100 persons (another 40 person) with 80GPM? I guess I would have to know of the chances that 32 persons use the shower at the same time?

    I would like to find a good handbook for sizing well pumps, tanks, and pipes. Any reccommendations?

    Luc

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    Moderator valveman's Avatar
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    I don't really like this chart but, it is the best I can find. Nothing is better than observing an existing system.
    Attached Images Attached Images  

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    Hmmmmm, maybe I scared him off!

    bob...

  11. #11
    DIY Member luc's Avatar
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    Thank you witch, valveman, and Speedbump for the advise on this post. It is a good start for our project. I like to analyse the different possibilities for every project and choose the more appropriate solution.

    I hope that this post was not an occasion for discord between different point of views and ways of doing things. In a forum everyone should be able to express themselves without hurting others.

    Best regards,
    Luc

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    I hope that this post was not an occasion for discord between different point of views and ways of doing things. In a forum everyone should be able to express themselves without hurting others.
    That's the reason witch "Rancher" was banned from this and other Forums (mine included). He was a trouble maker and if Witch isn't him, I apologize, but I would bet lunch that they are one in the same. Now he's back with another screen name causing trouble again. He has this affliction with Cycle Stop Valves. He can't pass up a chance to bad mouth them for some reason.

    bob...

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