Pressure switch question: 30/50 or 40/60?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Mike17, Feb 2, 2014.

  1. Mike17

    Mike17 New Member

    Messages:
    3
    Location:
    Charlotte, NC
    Hi folks,
    I was troubleshooting a low water pressure issue and confirmed that I had a clogged pressure switch & pipe (exactly as shown in a previous post: http://www.terrylove.com/forums/showthread.php?26229-Pressure-Switch-Repair-and-Replace-w-pics)
    Little background info, leading up to my question...
    We have a 3000ft house built in '84 with copper pipes, however some of the main (accessible) ones in the crawlspace have been replaced with PEX. We are on a well that's about 50' from the house. We have very hard water. When we moved in 6 years ago, house was in disrepair and had to have the pressure switch replaced (service guy put in a Square D 30/50), and blue pressure tank replaced (says Utilitech, 100psi - appears to be 36gal, not sure).
    About a week ago, the water pressure would drop after 5min in the shower, cut out completely, but then come back on after about 30 seconds. Yesterday, it took about 5min before the pressure came back and water would begin to flow. I turned on a faucet, went in the crawlspace and watched and the pressure gauge drop to 0 after about 7min (pressure switch did not engage at all). It would stay like that for about 5min and finally came back on by itself (or I could manually hold the contacts on the pressure switch to bring the pressure back up). I adjusted "nut #1" and cranked it down to see if it would affect the cut-in, but it didn't work. NOTE: I went to Lowe's today and they were out of the 30/50, so I went ahead and bought the 40/60 and installed it, since people were waiting on me to get the water back on... everything appears to be just fine. Had a nice shower, nice water pressure for the entire shower.
    My question is, knowing our system had a Square D 30/50, is there any harm in replacing it with a 40/60? (Isn't it just creating a little more water pressure for our family when we take showers?)
    One of my concerns is that over the past 5 years we have had a few copper pipe leaks show up and I had to get in the crawlspace and repair copper pipes that had become brittle (with PEX and the Sharkbite fittings, since I don't know how to do real plumbing). Also, when our washing machine is turned on and it "pulses" water into the machine (on/off, on/off, on/off), each time it does that it causes the pipes to move a little and be noisy --you can always hear the sounds of the water turning on/off in the pipes in the walls even when you're walking through the house. My concern is if the 40/60 could allow too much pressure on my pipes? Or am I splitting hairs over 10psi?
    If it's a big deal, and you guys think I need to change back to the 30/50, then I'll head back to a different HW store and get the other one. But if it's a non-issue, then even better.
    Any thoughts our suggestions you have would be much appreciated.
    Thanks!
    Mike
    Last edited: Feb 2, 2014
  2. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,217
    Location:
    Houston, TX
    You can adjust it if needed.

    It is the same switch, the factory just presets it.

    You adjust the big Nut in the middle.

    A CCW turn on the Big nut turns the pressure down.


    Good Luck.
  3. valveman

    valveman Moderator Staff Member

    Messages:
    4,473
    Location:
    Lubbock, Texas
    Yes it sounds like the nipple going to the pressure switch was clogged. I would replace the nipple with a 1/4X3 brass or Stainless nipple. Galvanized nipples tend to plug up quickly. Your pump should do 40/60 no problem. But you can make a 40/60 switch from a 30/50 switch if you need to by just tightening the large adjustment about 3 full turns to the right.


    That pulsing when the washing machine is filling with warm water maybe the cause of every leak you have had. That pulsing on/off causes tremendous water hammer throughout the house. Water hammer pulses can be 10 times higher pressure than your static pressure. If the average house pressure is 50 PSI, those pulses from the washing machine can cause 500 PSI spikes in rapid succession. No wonder you are having leaks.

    You can run the new washing machines on cold or hot, but never warm. On warm setting the cold water solenoid valve stays on while the hot water solenoid valve pulses on and off to make the water warm. This is some new “government regulation” that is supposed to save energy, but causes a string of negative side effects at the same time.

    I actually went to a used appliance store and got an old washing machine that doesn’t do that. I gave the new one away. Not only is the old washing machine heavier built and will probably last longer than a new one, but it doesn’t pulse on warm water setting.

    The higher pressure of a 40/60 switch is not a problem, and higher pressure feels better in the house. Even when the pressure switch was clogged and the pump couldn’t shut off, the pressure shouldn’t have gotten higher than 75 or 100 PSI. So it is not the working pressure that is causing your leaks. Thanks to government regulations, it is the water hammer from the pulsing washing machine that is causing your problems.
  4. 41Fever

    41Fever New Member

    Messages:
    23
    Location:
    North Dakota
    You now need to adjust the air pressure in your pressure tank to 2# below your cut in of pressure switch so 38#.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    Washing machines and anything that can turn on and off fast are candidates for the installation of water hammer arresters. Go to any big box store or hardware or plumbing store and you can pick up a pair of them for your washing machine. Get the version that has the hose fittings on them. THen, shut the water off, unscrew the WM hoses, install the arresters, then reconnect the WM hoses. That should solve, or significantly reduce the water hammer. IF you have a water line to your frig, you might want one for there as well. Those are the two fairly common places for arrestors in a house.
  6. Mike17

    Mike17 New Member

    Messages:
    3
    Location:
    Charlotte, NC
    Don -- glad to know. Thanks!
    Valveman -- this is super helpful. I appreciate the added insight regarding our washing machine. I liked your suggestion to not use the warm setting, only use hot or cold.
    Jadnashua -- I'll look for those water hammer arresters to learn more about them, sounds like a good tip.
    41Fever -- Thanks for the tip on the pressure tank. I turned off the system and drained the water out and checked it, and it was at 32#, so it sounds like I need to bring it up to 38#, if I'm understanding correctly?

    I'm so glad I stumbled onto this Forum. You guys are awesome and saved me a ton of headache and money. I'm just an "average Joe" and I try to DIY if I can: Plumbing is something I have zero skills in, so it was a very rewarding feeling to have been able to successfully diagnose and swap out the pressure switch - thanks to the info you guys shared in this forum. I didn't expect to get responses so quickly; very appreciated. I will look through the other forums here to see what else I can learn. Thanks again! Mike
  7. valveman

    valveman Moderator Staff Member

    Messages:
    4,473
    Location:
    Lubbock, Texas
    Even in more flexible plastic pipe transient pressure waves that cause water hammer travel at 3,000 feet per second. Water hammer arrestors may help, but it is like trying to catch a rifle bullet with you teeth. The transient waves will fly right past a water hammer arrestor. It is better to prevent water hammer than to try and catch it with an arrestor. Preventing water hammer requires that you don’t let valves quickly open or close on a high velocity line. Restrict the flow into the washing machine or refrigerator by choking back with the faucet. The machines will fill slower, but the valves won’t cause water hammer when the velocity is reduced enough.
  8. Mike17

    Mike17 New Member

    Messages:
    3
    Location:
    Charlotte, NC
    Valveman, I didn't think of turning down the faucets on the washing machine a little - good idea! I'll give that a try. Thanks!
  9. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,217
    Location:
    Houston, TX

    You can also install flow restrictor discs on the Washing machine hoses, they come in all sizes

    Some water shutoff valves will leak around the stem, If not fully open or fully closed.


    Good Luck.
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