Results 1 to 8 of 8

Thread: Keeping a RODI pump from short cycling

  1. #1
    New User
    Join Date
    Aug 2016
    Location
    63021
    Posts
    5

    Keeping a RODI pump from short cycling

    I'm trying to get some ideas as to how to keep a Rodi pressure pump from cycling when the water level fluctuates. The pump plugs into the Apex and when the reservoir is full, the mechanical float create back pressure which turns the pump off. The problem is that the float valve will fluctuate sometimes and the pump will turn on and off quickly. Is there a way to keep that pump from cycling based on the amount of current that it draws. It draws about . 5 amps when it's on and then zero when it turns off.



    I'm pretty much a programming newbie so any help would be appreciated.

  2. #2
    NSI Member
    Join Date
    Nov 2015
    Location
    Duluth, GA
    Posts
    157
    If you use the mechanical the float as a backup to a float switch connected to a breakout box. It will give you redundancy and stop the pump cycling.

    Set the switch an inch or so lower than the mechanical float and have the switch cut the power to the pump. If the switch fails the mechanical float will still shut down the pump.

  3. #3
    New User
    Join Date
    Aug 2016
    Location
    63021
    Posts
    5
    I'm trying to make due with what I have.

    I know the float will turn off the unit when it's full. So the current will go from 0.4 amps to 0.0 amps.
    I have tried creating a virtual outlet but the defer command is confusing to me. Old age...

  4. #4
    NSI Member
    Join Date
    Nov 2015
    Location
    Duluth, GA
    Posts
    157
    The problem you have is that the pressure switch is in the pump and your rodi system may have an auto shutoff. Those are outside the control of the Apex. Keeping the outlet powered isn't going to keep the pump running and it will still cycle on its own.

    The only way around that is to add something that the Apex can control. In this case a float switch connected to a breakout box will cut the power when the switch closes.

    The best way would be to use a solenoid valve that will close instead of controlling the pump with an outlet on an EB. Then the whole system will shut down at one time. There are sources for finding plans to make your own breakout box pretty cheap. All in all your looking at about $60 for everything, including the solenoid.

  5. #5
    Frequent Visitor
    Join Date
    Sep 2013
    Location
    Rhode Island
    Posts
    113
    Zombie had replied to a thread where the OP wanted to do something similar. Take a look: https://forum.neptunesystems.com/sho...on-power-usage

  6. #6
    NSI Member
    Join Date
    Nov 2015
    Location
    Duluth, GA
    Posts
    157
    Yes, but this is different. Zombie's solution in that post will work on pumps that aren't controlled by another means. In this case the booster pump has a built in pressure switch and possibly has an auto shutoff valve after that pump. Keeping the outlet in an on state longer will do no good here. The only thing that will turn the pump back on is a drop in pressure... or a faulty pressure switch.

    So, using those existing features as a backup here makes the most sense, by shutting the flow off before the mechanical float starts closing. A solenoid valve will do that and stop the intermittent off/on caused by the float not closing all the way as the container nears being filled.

    That pump oscillating is probably blowing some brine out of the RO membrane which will chew through DI resin too.

  7. #7
    Frequent Visitor
    Join Date
    Oct 2015
    Location
    CHICAGO
    Posts
    54
    How about a small (inexpensive) pressure tank ( https://www.bulkreefsupply.com/rever...ized-tank.html ) between the float and the RO system.

  8. #8
    Frequent Contributor zombie's Avatar
    Join Date
    Dec 2013
    Location
    Denver, CO
    Posts
    10,423
    I would use floats or opticals and solenoids to do it the right way, but since I enjoy a challenge, I think this would do what you ask where X is half of normal run wattage. This will stop the pump for 12 hours anytime it changes state from drawing current to not drawing current.

    BoosterON
    Set OFF
    If Output PumpName Watts > X Then ON
    Defer 000:10 Then OFF

    BoosterOFF
    Set OFF
    If Output PumpName Watts > X Then ON
    Defer 000:05 Then ON

    StopBooster
    Set OFF
    If Output BoosterON = ON Then ON
    If Output BoosterOFF = OFF Then OFF
    Min Time 720:00 Then ON

    Booster Pump Outlet
    Fallback OFF
    Set ON
    If Output StopBooster = ON Then OFF



    Sent from my SM-G965U using Tapatalk

Bookmarks

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
  •