(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 6 of 6

Thread: Should i use 1/2 " or 3/4" pex?

  1. #1
    DIY Junior Member dp200's Avatar
    Join Date
    Feb 2013
    Location
    fredericksburg
    Posts
    3

    Default Should i use 1/2 " or 3/4" pex?

    I have 3/4" water coming in to my hot water heater and then 1/2" to everything else.
    I live in a single wide trailer 70' x 14'.
    not sure if distance matters.
    I have seriously low pressure.
    takes 18 minutes to fill garden tub.
    I am remodeling plumbing due to water leaks in old grey pipes that are no longer legal and my insurance says I have to upgrade by may.
    I want to use pex.

    am considering using 3/4 inch throughout and then 1/2" to fixtures.
    does this end up increasing my pressure?
    does this increase my electric bill due to hot water sitting in lines?
    is it worth the extra money to increase size?
    do fittings inserted in pex decrease flow?

    I need help deciding.

    also need help deciding on connections.
    sharkbite, clamps, or whatever else is offered. crimps etc.
    which is lower cost?

    pipes will be under trailer exposed to cold but not in daylight.
    I am considering using the insulator sleeves to wrap pipes.

    any ideas, suggestions as to the proper way to do install under a trailer?

    thank you!!!

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,437

    Default

    Increasing the diameter of the pipe should supply greater volume, but it won't do anything to the pressure...don't confuse pressure with volume. I'd check the actual pressure you have - HD and any hardware store, sells a water pressure gauge. It's the only real way to know what you have now. Because it can freeze there, you want to make sure the pipe is run as close to the floor with insulation under it so that it traps some of the trailer's heat. Pex won't typically split if it freezes, but fittings can. Remember, insulation doesn't create heat, it just traps it. If there isn't any, the pipe will still freeze.

    3/4" pex is about the same ID as 1/2" copper, so yes, I'd run 3/4" pex to the bathroom group. The tub, I'd convert 3/4" to the likely 1/2" valve you have. Everywhere else, things are flow restricted, so 1/2" is plenty. Well, a washing machine might use the 3/4" up to it as well as a hose bib.

    Yes, larger pipe will hold more water, and let it take longer to get hot at the end (a recirc system might work out for you if things actually have to go that full 70'). But, as I said, 3/4" pex isn't much larger than 1/2" copper.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    DIY Junior Member dp200's Avatar
    Join Date
    Feb 2013
    Location
    fredericksburg
    Posts
    3

    Default

    thank you jim! any insight as to the best connectors to pex? I guess the number one consideration is the weather as you said typically fittings can split. are there better fittings than others?

    (and I will definitely install those wrapper insulation sleeves around pipes and I have extra strips of insulation I can probably wrap as well).

    messy job but I am certainly digging getting under the trailer and getting dirty.
    started out with leaking fixture that soaked much insulation.
    ripped out all insulation and now see MANY dripping fixtures.

    I guess fixtures are my real problem.
    any suggestions as to best fixtures are greatly appreciated.
    thank you sir!

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,437

    Default

    It's hard to say what a trailer had, or whether 'standard' valves, etc. will fit easily. There are lots of discussions on pex, so a search and some reading time will help. Personally, I like Wirsbo/Uphonor, but their connection system requires a fairly expensive tool to make connections. I don't have enough experience with others to tell you what to stay away from.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5
    DIY Junior Member 6t7gto's Avatar
    Join Date
    Jan 2010
    Location
    Bedford, Ohio
    Posts
    46

    Default

    Quite a few pex crimpers on e-bay.

    buy it, use it, and put back up for sale.

    david

    p.s. interesting that I couldn't put up the link for e-bay.

    Not if you consider all the spammers that like to sell here
    If someone wants to tell about a product, fine. If you want to add a shopping link, not so okay.
    Terry
    Last edited by Terry; 02-07-2013 at 02:01 PM.

  6. #6
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,679

    Default

    Larger pipes will increase volume and should increase "dynamic" pressure. Insert fittings are an enigma. They do reduce the size of the line, but since it is for a very short distance, the water should compensate by moving faster at that point.
    Licensed residential and commercial plumber

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •