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Thread: attic tank to increase pressure/flow

  1. #1

    Default attic tank to increase pressure/flow

    I'm trying to innovate a problem that I got myself into. The problem is we have four full baths in a house that originally had one full bath. The plumbing is pretty new, including a brand new line right to the house, It's 1 inch and then immediately reduced to 3/4 inches. Problems really started happening after the water line replacement but I have checked the pressure and it is 60 psi wherever I check it if no water is running. If one shower is on, it immediately drops to 20 or lower. If I am filling the jacuzzi bath, the shower and sink upstairs actually begin sucking in air. So I'm assuming I have a "flow" problem and not a "pressure" problem. It seems I need a larger pipe diameter leading to each bath to increase flow. But even that might not be enough. And that would be too much work especially considering that it's all new pipe. I'm considering a gravity option for the baths on the second floor. We have a large attic that could have a tank, and to connect to baths would be easy. (we have a tall, narrow row house. I'm also thinking about solar hot water collectors on the roof (long flat roof facing south) and feeding them right to the water tank in the attic. But will it correct the pressure/flow problem? Do I need to pump the water up the tanks in the attic or can it just trickle in until it's full. Will gravity provide enough pressure or do I need a pressure tank and pump to fill it? Grateful for any advice.

  2. #2


    Assuming it was working fine before the new line install from the street, were the street and main shut-offs re-opened all of the way after the install?

  3. #3
    Computer Programmer Bill Arden's Avatar
    Join Date
    Sep 2006
    MN, USA


    Quote Originally Posted by Erico63 View Post
    I'm considering a gravity option for the baths on the second floor.
    Figure 15 PSI per 30 foot of height.

    This means that you would have to have the tank at 120 feet above the house to get 60 PSI.

    A standard bladder tank is a better option.

    It does not matter where the tank is located since the water pressure is a lot greater than the pressure due to the height.
    Important note Ė I donít know man made laws, just laws of physics
    Disclaimer: I'm a big fan of Darwin awards.

  4. #4
    Aspiring Old Fart, EE, computer & networking geek Mikey's Avatar
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    Nov 2005
    Central Florida


    At what point in the system did you check the pressure? Whatever the problem, it's upstream from that point.

  5. #5
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona

    Default flow

    If the pressure drops from 60 psi to 20, and the upstairs baths suck air you DO HAVe a pressure problem, and you have to find out where it is happening. It is almost impossible for your usage to deplete the city supply to the point where its pressure drops that much, so you either have a serious restricion in your line restricting the flow, and thus the pressure, or a failing pressure reducing valve on the line that starts out with adequate pressure but cannot produce it on a constant basis. A pressure tank anywhere in the system would be a bandage for a short term solution, (i.e., for a minute or so), but on a constant basis its pressure would be the same as you now have, because it would be constantly equalizing with the system trying to raise the pressure when it drops, thus using up its stored pressure.
    Last edited by hj; 03-20-2008 at 07:18 AM.


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