I have a 3 foot deep sump approximately 16 inches in diameter in my basement. Recently I had a flood due to the vibration of the pump moving it so that the float caught on the side of the sump.

On doing some reading while the tethered ball is a fairly reliable system, this is a well known problem.

I would like to replace the ball with a sensor with no moving parts.

The ideal sensor/controller:

  • Has no moving parts at all.
  • Is totally unaffected by crud, corrosion
  • Can control a 1/4 to 1/2 HP pump.
  • Is self diagnostic.
  • Has an alarm.
  • Doesn't cost the earth.

The simplest way I can see to do this would be with an ultrasonic range detector operating in a section of pipe with open bottom place in the sump. (This eliminates odd ball reflections from the sump pump and the backup sump pump.) Once every N seconds it pings the water level, and at L(bottom) turns off the pump at L(start) turns on the pump, and at L(alarm) attempts to wake the dead.

One implementation of this is here: https://www.youtube.com/watch?v=9pN6AZyQq48

However it's not in production.

I have found ways to do this with an Ardino and a ultrasonic generator/detector, but I would rather pay for a solid canned solution, not being confident that a home rolled circuit would be sufficiently robust.

In response to comments below:

"Fix it so that the ball cannot get caught"

The sump right now has two pumps in it: The main pump, and an auxilary battery operated pump above it in the event of a power loss. (It's happened...) The battery has the capacity to run a couple dozen pump cycles. It's on a smart charger.

The present configuration has worked for two years with no problems. Then the float got caught. Merely touching the riser pipe freed it. I didn't see the float move (to dark to see it at all) so it may have been a bad contact somewhere. Right now I don't know the failure mode.

However, you do have a good idea: There are steps I could take to keep the pump from shifting.

One sure way to make the float less likely to catch is to shorten the tether. At present the pump cycles on for 25 seconds. I would prefer to have a longer cycle. I considered a lower capacity pump

Re: Caged floats. I will check into that. The problem I've seen with the old style float on a rod operating a mechanical switch was that the switch would fail, or the rod would corrode and no longer move. So far the only caged switch I've found (Basement Watchdog) have very short travel -- about 4-5 inches. I'd like to have 16-24 inches to reduce the number of cycles per hour. (In spring during snow melt, it can cycle once every 90 seconds)

I would also like some form of alarm if the pump doesn't operate. The ones I've tried are not audible from the main floor. My workaround at present is a pair of wires soldered to the text circuit on a smoke alarm, with the wires hanging free in the sump. Inelegant.

  • 1
    With a properly installed sump pump, you will never have trouble with the floating ball. Unfortunately someone took a shortcut that allows yours to become wedged somehow. Don't reinvent here, fix it so the ball can't get stuck. – Tyson Nov 13 '16 at 17:48
  • You can also buy a caged float (dual float, even) retrofit controller for not much money, but without all the "keep it complicated, genius" features you want for not much money. KISS tends to win in the real world... – Ecnerwal Nov 13 '16 at 19:52

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