Why does it state "Do not reduce pipe size"

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by kozaz, Jan 7, 2010.

  1. kozaz

    kozaz New Member

    Jan 7, 2010
    I bought a house, it's on a share well. The well pumps water into a holding tank. Everybody has separate lines running from the holding tank to their homes.
    At the home, I have a pressure tank and flowtec pump to pull water from the holding tank.

    I want to replace both the pump and pressure tank. (Leaking and suspecting the bladder in the pressure tank is leaking)

    Factory Advice for Pressure Tank and Pump Plumbing:

    The pressure tank has 1 and quarter inch fitting.
    The pump has a 1 and quarter inch inlet and a 1 inch outlet.

    The manual states "These sizes should not be reduced".

    Plumbing from storage tank to house:

    The PVC pipe from the storage tank to the house runs about 150ft and is 1 inch. This line is then reduced to 3/4 inch copper pipe. This 3/4 inch copper is the home's core plumbing size (it's a manufacture home).

    Current plumbing at the pressure tank and pump:

    The current pressure tank and pump are located next to the house. At this location, there's a "from storage tank" line and a "to house" line both are 3/4 inch copper.

    The current (old) system has the 3/4 inch copper line "from the storage tank" which is increased to 1 inch. Then the pump intake has the 1 and quarter inch reduced to 1 inch (Fitting).

    The pressure tank has the 1 and quarter reduced to 1 inch (fittings), then 1 inch pipe to the 1 inch pump outlet fitting. Then runs as 1 inch pipe, which is further reduced to a 3/4 inch copper line "to the house".

    The current system has ran with the above plumbing setup for at least 5 years with no issues. I also believe that the pressure tank is 7 years old according to the previous owner.


    Should I replace the plumbing between the pump and pressure tank with the recommended pipe size even though the "from storage tank" and "to house" copper lines are 3/4 inch?


    Can I run 3/4 inch plumbing between everything? What are the long term or short term problems I could encounter?

    Sorry for so long, but I'm trying to cover everything in detail.
    House has 2 baths, pressure tank is 50 gallons, pump is 3/4 hp, and only 2 people live in the home.

    Last edited by a moderator: Apr 3, 2010
  2. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    Normally, a two bath home uses 1" pipe at the beginning.

    A run of 150 feet will have some friction loss. but the 1" line should be fine.
    If your pipes are keeping up now, I would leave it.
    Last edited: May 18, 2011
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  4. masterpumpman

    masterpumpman New Member

    Mar 26, 2007
    Consult and Teach Well Drilling Internationally
    Virginia Beach, VA
    I would pay attenton to what Terry said. However I would also suggest that if you are replacing the pump and the tank (if the tank is seven years old), consider installing a Pside-Kick www.cyclestopvalves.com with your new pump. This will give you a constant pressure while drawing a variable flow (like city water pressure). You're family will love it.
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