(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 4 of 4

Thread: switch for two tank pumps control

  1. #1
    DIY Junior Member GeneMN's Avatar
    Join Date
    Sep 2012
    Location
    Minnesota
    Posts
    2

    Default switch for two tank pumps control

    I have a small greenhouse with a two tank cistern--graywater and rainwater with a pump in each tank--and need to switch automatically from the graywater pump when it is nearly empty to the rainwater pump. All I've been able to find are on/off switches; what I need is the equivalent of a three way electrical switch from one circuit to another.

    Does such an animal exist? Any help appreciated.

    If a moderator is here, will I be emailed if someone replies? Or do I have to keep checking? Thanks.
    Last edited by GeneMN; 09-02-2012 at 09:32 AM.

  2. #2
    DIYer, not in the trades LLigetfa's Avatar
    Join Date
    Feb 2011
    Location
    NW Ontario, Canada
    Posts
    3,689

    Default

    If your pumps are 120V, a simple 3-way (SPDT) light switch would do it. Common as borscht.

    For 240V you would need a DPDT (double pole, double throw). Harder to find.

  3. #3
    DIY Junior Member GeneMN's Avatar
    Join Date
    Sep 2012
    Location
    Minnesota
    Posts
    2

    Default

    Thanks. Yes, 120V. That was my first thought, and would be a good solution to do it manually. However, I need it to function on it's own. The circuit is on a timer to control the total amount of water pumped. I need a way to check and empty the graywater tank first, then switch to the rainwater for the rest of the time. When more graywater comes in, it resets to that pump. I thought of making a mechanical Rube Goldberg design using a 3 way switch and a float valve, but this is sketchy. I checked with the plumbing shops locally, and they knew of no such switch.

  4. #4
    DIYer, not in the trades LLigetfa's Avatar
    Join Date
    Feb 2011
    Location
    NW Ontario, Canada
    Posts
    3,689

    Default

    Sorry, I didn't get that you wanted "automatic". I see you updated your OP since.

    I think you are not likely to find a canned package and will have to make your own from a float switch and a simple DPDT relay. A float switch in the grey water tank as used for a sump pump would work to energize the relay and pump. When the switch opens, the relay falls out and "flops" to the other pump.

    A flip flop (AKA latching) version would need energy from one source to flip it and energy from another source to flop it so two floats would be needed; a low limit and a high limit.

Similar Threads

  1. ONE pressure switch controlling TWO pumps?
    By NealinNevada in forum Pumps and Tanks Well Forum & Blog
    Replies: 2
    Last Post: 08-10-2009, 02:29 PM
  2. Possible Defective Pressure Control Switch
    By one900steve in forum Pumps and Tanks Well Forum & Blog
    Replies: 3
    Last Post: 04-02-2009, 04:25 AM
  3. Pressure Control Switch cut-out at 33 psi?
    By one900steve in forum Pumps and Tanks Well Forum & Blog
    Replies: 0
    Last Post: 03-23-2009, 10:21 AM
  4. Remote control load switch?
    By snafflekid in forum Electrical Forum discussion & Blog
    Replies: 2
    Last Post: 08-04-2007, 02:26 PM
  5. Cistern pump control switch
    By NealinNevada in forum Pumps and Tanks Well Forum & Blog
    Replies: 8
    Last Post: 05-09-2007, 07:31 AM

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
  •