Re-piping my house with copper (layout and sizing)

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by nola000, Mar 14, 2013.

  1. nola000

    nola000 New Member

    Sep 25, 2009
    Southeast Louisiana
    Does this look like a good idea?

    Plumbing Repipe.jpg
  2. Hairyhosebib

    Hairyhosebib New Member

    Jun 23, 2010
    I would keep the hot water line at 3/4 inch. When you pipe the hot water to the far right tub I would add a 3/8 copper line and return it back to the bottom of the water heater. This is called a HYDRAULIC LOOP. If it is all on the same floor you might need a circulating pump to pump it back to the bottom of the water heater. Remove the crappy plastic hose bib and install a nipple, a tee, a check valve, a union and a valve. It could be 3/4 inch too. This line should be metal and insulated as well. You can re install the crappy plastic hose bib if you want but I install a full port 3/4 inch ball valve with a hose thread adapter on it. You will get hot water very quickly doing this. If the water heater is in a basement then the natural flow of hot water rising will force cooler water down to the water heater without a circulating pump.

    If you are using a brand new water heater that you purchased from a store like Home Depot, return it and get one from a good plumbing supply house. I purchased a GE brand from HD, it did not last 6 months. Two holes formed in the tank. COMPLETE CRAP!!
    Last edited: Mar 15, 2013
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    A "gravity circulation" system will ONLY work, if the hot water line slopes continuously upward to the far end, and then the "circulation" part is below it and slopes continually downward back to the water heater. ANY "jog" upward or downward to cross beams, etc., will negate the effect and it will NOT work. The 1/2" hot line will work, UNTIL two persons want to use the hot water at the same time. The lateral lines to the faucets off the main line only have to be 1/2".
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