Timer available for Dankoff?

hillsidehillside Registered Users Posts: 54 ✭✭
I have a water system using 3 tanks for a total of 2000 gallons, a Dankoff 24V slow pump (with dry run cutoff switch) and solar powered. Everything works great, especially after the good advice I got here a while back about a better quality charge controller (batts. no longer percolating).
When we leave the house, the power to the system is turned off, but sometimes we forget.
Now, my concern is, if one of the many pvc water lines around the property breaks, (even during the night when we're home) the pump will keep pumping until the tank(s) are dry and then go into Dry Run switch mode. I don't want the pump to run dry for one second, much less than the several minutes it would take to overheat and the switch to cut off power. (Providing I've wired it correctly!)
I don't know if the pump would be damaged during this time or not. But I'd hate to lose 2000 gallons of water also. Is there such a thing as a timer that could regulate the pumping time and shut off the pump if it goes over that time.? It takes the pump 4 & 1/2 minutes to fill the pre-charged tank, so a timer set to go off at say, 6-8 minutes would be ideal.
It would have to be 24v compatible...or not?
Thanks

Comments

  • hillsidehillside Registered Users Posts: 54 ✭✭
    I guess not.
    But, it's a good idea, mr. hillside.
  • BB.BB. Super Moderators, Administrators Posts: 29,489 admin
    I am looking around... There are a lot in the $150 range (PLC -- programmable logic controller).

    What I am think about is a relay with time delay.

    Pump switch turns on (and supplies power to the relay).
    Relay set (for example) to 5 minutes. If pump is on less than 5 minutes (water pressure switch turns off), Relay resets timer to zero.
    Relay turned on for > 5 minutes, it turns off the AC to the Water Pump until you manual reset...

    I don't think you need a $150+ PLC to do that... Hopefully somebody else has better suggestions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillsidehillside Registered Users Posts: 54 ✭✭
    Thanks, Bill. I couldn't find anything in my searches..seems like it's plausible..but needs to be simple and affordable. And it'd have to be DC powered. That would use some battery power but not that much the way you've described, if it's only powered when the pump turns on.
    Meanwhile I'll trust the pump overheat switch and keep an eye on the water lines!
  • AnawaAnawa Solar Expert Posts: 211 ✭✭✭
    Not knowing how your system is configured, will a float switch in one of your tanks work to open (or close) a wired circuit? I use a float switch in my tanks to control submersible pump start-up.

    Paul
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
  • BB.BB. Super Moderators, Administrators Posts: 29,489 admin
    I sort of see the problem to be solved as--The pump never runs more than 10 minutes in normal operation... If the pump runs for 20 minutes, turn off until manual reset. If the pump turns of in less than 20 minutes, then reset the dead man timer.

    This reduces chances of flooding and/or killing the battery bank.

    Perhaps something like this would work: Omron H3Y-2:

    https://www.ia.omron.com/data_pdf/cat/h3y_ds_e_7_1_csm92.pdf?id=196

    Less than $5 + shipping from Ebay for 12 VDC unit.

    Connect the output to the pump controller's float switch control input.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillsidehillside Registered Users Posts: 54 ✭✭
    It's a fairly simple 2 battery 24 v system to the Dankoff 24v pump, drawing off either 1, 2 or 3 tanks totaling 2000 gallons. I usually have only one tank open at a time as we get a lot rain at this time of year and I can collect 200-300 gals. in one afternoon of rain. (Puerto Rico)
    Paul, not sure if I could put a float switch in the bottom of one tank...are they submersible? Tanks are poly, two are 650 gal., one is 800. They are plumbed together but valved so I can draw from any one, or all. I only draw from one at a time.
    I like the simplicity of this setup. Easy to put together and trouble shoot. The overheat switch that I bought for the Dankoff should work as advertised..wonder if anyone has ever had one save their pump. It has to run dry until the pump gets hot..
    Thanks for the replies guys.
  • AnawaAnawa Solar Expert Posts: 211 ✭✭✭
    A float switch is a simple device and available in a few different designs. If you Google "water tank float switch" and click on the Images, you can get a idea of how they work. There may be a configuration that would work for you.

    If I understand correctly, you use the Dankoff to pressurize your system and you do not want your pump running when the water level is "down". Float switches are usually designed to "turn-on" a pump when the water level is low, but in your case, you want to "turn-off" the pump at low water. Perhaps some creative engineering to wire a circuit to "open" when the float switch is in the "down" position is what you need. Some of the forum contributors and/or members may help with this.

    I too have my tanks piped in series (2 ea. - 1500 gal) so that the water level is controlled by a single float switch. I use the float switch device to activate a submersible well pump to fill my tanks. If you decide a float switch will work for you, then you may want to install an "overflow" pipe just below the top of a tank that will set a consistent top-most water level. Float switches work best with well established operating parameters.

    Paul
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
  • AnawaAnawa Solar Expert Posts: 211 ✭✭✭
    I have three separate water systems linked to my storage tanks: gravity-feed for garden irrigation, a 12volt DC Dankoff pressurized utility set-up at the garden station, and a 240AC Grundfos booster pump at the house.

    I'm not sure what happened this winter, but I recently found the Dankoff not working and I noticed the dry-run switch had been "activated". Meaning, the waxed-end piece enclosing the reset button had melted away. So apparently the dry-run switch worked as intended because the man at the local auto electric repair shop told me that the pump was working just fine. I haven't reinstalled the Dankoff pump to check it out so I can't report that everything is okay, but a couple of things worth noting. First, if you have problems with your pump, save time and money and take it first to a local auto electric shop. I got this advice from reading some of the Dankoff literature. Second, I still don't know what to use to "re-seal" the melted wax at the dry-run switch. I've got to much other stuff to do around the place to try and figure this out right now.

    So, hillside, just a long way to let you know the dry-run switch on the Dankoff works, but you are on your own if you find it used.

    Paul
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
  • hillsidehillside Registered Users Posts: 54 ✭✭
    thanks for the info. If your pump is undamaged, great. If my dry run switch does what yours did, I'd probably go for a new one.
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