Pressure switch setting for small tank

Discussion in 'Pumps and Tanks Well Forum & Blog' started by techinstructor, Aug 16, 2013.

  1. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    I had to replace a pressure switch on a 2-gallon pressure tank. I don't know what the pressure settings were on the faulty switch. The new switch (one I already had purchased for another purpose) was preset to 60/40. At that setting water pressure is much steadier, but the pump is cycling on and off rapidly and I know this is very bad for the pump. I know the best solution would be to get a larger pressure tank, but I can't install one right now.

    So.... What is the best pressure setting to use for this small tank?

    When the OLD switch was on the tank, I think the water pressure would get up to 60, but I know it fell much lower than 40 and the timing of the cycle, from high pressure to low, was longer... 45-60 seconds.

    Thanks in advance for your help.
  2. wondering

    wondering Member

    Messages:
    106
    Did you check your air pressure in the tank when you changed switches? With the 40-60 switch you should have 36-38 psi air in the tank.
  3. craigpump

    craigpump Member

    Messages:
    988
    Location:
    ct
    Two gallon tank? You better save some money for a new pump as well.
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,522
    Location:
    Lubbock, Texas
    You can get by with the 2 gallon tank if you use a Cycle Stop Valve to stop the cycling.
  5. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    This sounds like it is exactly what I need. I'm researching this now and hope to purchase one as soon as I'm sure of which model will work best. Meanwhile, would it help at all to adjust the pressure to a lower setting, e.g. 30/50, or with a greater span between on/off e.g. 30/60?

    We've been running the pump (Myers Predator 1 hp) with the old switch for 4 years and amazingly it has lasted, but I'm really worrying that it's just a matter of time before the pump burns out. I know that is going to be a major expense. I don't want to hasten its demise.
  6. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,349
    Location:
    Houston, TX
    Changing the setting its not likely to help very much with that small of a tank. Unless you change the differential. And the span on most of them switches can be hard to set, but can be done, +- 5 psi or so.

    A bigger tank or ,

    http://www.cyclestopvalves.com/index2.html
    Last edited: Aug 17, 2013
  7. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    Thanks Don L. I suspected that was the case.

    I have question about the CSV1. I understand the CSV1 comes in models, 130, 140, 150 and 160. If I understand correctly the last two digits correspond to the CSV pressure setting, i.e. 30, 40, 50, and 60 respectively. So if my pressure switch is set at 40/60, it seems like I could run any but the lowest CSV models. Are there any problems with using the 160? One can always decrease the flow rate on the outlet end but if the pressure is too low, then the flow will also be slower so the higher setting would seem to be the best. Please correct me if I'm misunderstanding this.
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,080
    Location:
    NW Ontario, Canada
    Running higher pressures will reduce the drawdown potential of any tank but on a 2 gallon tank, the difference is minimal, maybe .12 gallons. At 40/60, you should have about .54 gallons of drawdown.
  9. valveman

    valveman Moderator Staff Member

    Messages:
    4,522
    Location:
    Lubbock, Texas
    With a 40/60 pressure switch you can use a CSV1-50. However, a CSV1A is preferable because it is adjustable, and better suited for indoor installations. Without a CSV, turning the pressure switch setting higher will reduce the cycling. But if you turn it up a little too high and it can't turn off, you will melt down the pump.
  10. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    Thanks a bunch for all the information.

    I have ordered a CSV1A. I just wish I had done this sooner. :)
  11. techinstructor

    techinstructor New Member

    Messages:
    81
    Location:
    North Carolina
    Is it ok to use Oatey Great White Pipe Joint Compound in lieu of teflon tape on the threads when installing the CSV1A? When installing other brass fittings, we've found it works better than the tape to seal the threaded joints. The installation instructions say to use tape, but we would prefer this product. Please let me know if you know of any prohibitions in this application.

    Thanks
  12. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,349
    Location:
    Houston, TX
    Not sure you can even get REAL teflon tape anymore.

    I have never had a problem with it.

    It is not good to use on compression fittings, nothing should be used on them.

    I would think what you use is OK, but I have never used it. It does look like good stuff.

    Maybe a Pro that has used it will stop by soon.


    Good Luck.
    Last edited: Aug 23, 2013
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