A DIY appliance shutoff system (md)


I need a way to shut off an appliance if it’s dumping water too fast for the drain, because reasons. I have a [[http://www.getfloodstop.com/][Floodstop]] for another appliance, it works well but it’s pricey, and works with the water line instead of power, which is what I need. Tight space constraints prevent me from using something like [[https://www.amazon.com/gp/product/B00988NOV2][this]]. Guess that means I have to make it myself…

  • Ideas
  • disable water or power?
  • DIY float switch, integrated into standpipe
  • plumbing fixture to attach to standpipe
  • Version 1 Ultimately, the simplest, cheapest thing won:
  1. Attach a tee fixture to the standpipe, as a makeshift overflow fitting. This was harder than it sounds, because

    • The 50-year-old cast-iron standpipe is a nonstandard size. There is no great way to attach modern PVC to this. Companies like [[https://www.fernco.com/plumbing/flexible-couplings][Fernco]] make flexible fittings for exactly this purpose, but getting the size right is critical - if it’s not watertight, it doesn’t work.
    • There is very little vertical space in the drain box. Of course I could enlarge it, but if I’m going to start hacking at the drywall then that opens up a bunch other options for dealing with this. I want to leave the drywall as it is, for now.
  2. Overflow drains into a bucket with a float switch attached.

  3. Float switch connects to a relay.

So if the drain backs up, it overflows into the bucket, lifting the switch, triggering the relay, shutting off the appliance.

** Final parts list:

  • Tee fitting ($12)
  • 2" PVC ($.25 ?)
  • 2" to 3/4" barb fitting ($.50 ?)
  • 3/4" hose ($10)
  • bucket ($3)
  • float switch ($1.50)
  • relay ($25)
  • miscellaneous wire, connectors, etc

Total materials cost: about $50

Total labor time: less than one hour

Total design time: way too much

Worth it? Who knows.

  • Pictures


/How it looked before I started/


/Everything I could find at the hardware store that might work/


/A better option, from a local shop, and the other fittings to get it to drain to the bucket/


/The overflow setup/


/The full setup/


/The relay setup/


/Hose size comparison/


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