OT: Electronics help debouncing a float switch

[Bob Engelhardt]

If this continues to be a problem, why not pull the toilet and put a test plug in the pipe? DWV plumbing is tested at 5 psi IIRC, so the plug would hold at least 10' of head.
https://www.homedepot.com/p/T31004/100141500

[Cenedd]

It's a good suggestion Bob but there's a branch to the washing machine and sink so it'd just come out elsewhere. Could maybe cap that too but then I've got to run a similar system to drain the washing machine. I'm told that it's not optional!

[wmgeorge]

What Mr. Tiers suggested a check valve in the drain lines and a call to your Code people about the construction/plumbers who did the job.

[genea]

Try raising the float switch higher in the bowl to reduce the sensitivity of the switch. Maybe.

I don't know the travel range of the switch or the capabilities of the pump, but it seems to me that given the small cross section at the bottom of the bowl the switch wouldn't have to run very long to reduce the level by a mm or two, possibly enough to shut the pump off. If you raise the switch 100 mm or so the volume pumped would have to be several times greater (maybe even 10x by the looks of it) before it shut off again. That's still not a very high volume though.

Something like this, assuming the problem is with the float or float switch should help.



The drawing starts with the sump empty, all contacts open
Level rises, stop switch contacts close but there's no voltage on the relay coil until the start switch closes
Level rises farther, start switch closes, relay is activated, pump starts (top relay contacts), power is applied to the relay coil through a second path (bottom relay contacts)
Pump, pump, and pump some more
Level drops, start switch opens, stop switch remains closed, pump continues to run
Level drops farther, stop switch opens, relay is deactivated, pump stops, all contacts are open again

You might want a fuse and over temp cutout on the pump line.

[deltap]

Find where the excess clear water is entering and disconnect it. It costs real money to treat clear water at the treatment plant. For this reason municipalities in my area forbid floor drains, sump pumps, roof drains, and the like from entering a sanitary waste line. If you are caught doing it you will be fined. Get a qualified plumber who understands this to take care of it. Plumber can clear the drain to the city main. If it's still obstructed, the city has responsibility. If your lateral is too old, broken, or plugged with roots, you will have to replace it at your expense. Quit screwing around with band aid measures. BTW save your pics. The plumber will have a good laugh over them and may lower the bill.

[Cenedd]

genea Ah, genius; I like it! Given that the pump is also 12V and running off the same PSU, I could probably do this without swapping to a double relay too. I'll see if I can get some sort of timescale to see if it's worth putting in the extra effort (would need to make up an additional mount rod for the second switch) to refine the 'solution' or not.

deltap The screwing around is just breathing room so things don't become unsanitary/uninhabitable before things get fixed. Shared drainage between two houses, no maps and a lost concreted-over manhole really don't help either. I can't disconnect the rain water as it's next door's rainwater going into their drain on their property that's coming back up mine - were it not shared, it wouldn't be a problem. The long term solution is to disconnect from that drain but that means digging up the kitchen and the garden. We still need to fix the actual blockage though - partly for a better breathing room solution and partly because otherwise it'll just wash out our foundations or cause damp.

[J Tiers]

....................... I can't disconnect the rain water as it's next door's rainwater going into their drain on their property that's coming back up mine - were it not shared, it wouldn't be a problem. .................

I am assuming yours is connected in upstream from their rainwater , and their drains connection is further downstream from either. So the blockage is in their piping between the rainwater and their drains.

You'll be wanting them separate, because if not, then any blockage after their drain, that causes backup on their side will naturally be blamed on you.

[Cenedd]

Yes, there's - and I'm extrapolating based on observations - a Y junction between what is now my downstairs toilet drain and their rainwater drain. We believe there is a blockage between that Y junction and the manhole. Before the junction and we wouldn't get their rainwater. as fas as the manhole and it would affect all the drains that join tha manhole and we'd have problems all over the place.

Legally speaking - from my understanding - it's entirely their responsibility as it is under their land. But these things are rarely that simple and as you say we could be blamed for what we have put down said drain believing - in the absence of maps - that it was ok. It is entirely possible that the problem predated our change but our output worsened the problem. But beyond that, I don't feel that a conversation along the lines of "It's all your problem and all your expense" is the most productive way of handling things - let alone fair. We definitely need to disconnect from that drain but we also need to cap it off and fix the issue as it won't just go away.

[wmgeorge]

Sounds like zero building codes or plumbing codes? Where do you live, rainwater is not suppose to enter the sewage system but sometimes its grandfathered in, but not sharing a house sewer drain to the street!!

[Cenedd]

Where do you live

About 4000 miles from you near London. Perfectly normal for rainwater and sewage to be a combined service but can only be mixed - from my limited knowledge - after they get to the manhole....and therein lies the reason everything has to be dug up again.

[wmgeorge]

About 4000 miles from you near London. Perfectly normal for rainwater and sewage to be a combined service but can only be mixed - from my limited knowledge - after they get to the manhole....and therein lies the reason everything has to be dug up again.

Your "manhole" is connected to a complete sewer system that flows or is pumped to a sewage treatment plant. Plants are designed to process sewage, not gallons and gallons of rainwater. As a result the untreated waste now will bypass the treatment plant and be dumped with raw sewage into the river or where ever it goes after the plant.

Well it seems your system is very much like ours, but sharing a Lateral from the main system does not seem to be. Your Drains, Pipes, and Water and Sewage Systems – SSE

In any event that plugged section of the line needs to be cleaned out, a pump is not going to solve that.

[JRouche]

I am late. A debounce circuit? Wrong place to ask. We have some of the best electronics folks in my opinion, JR

I dont know? A rubber band.. JR

But in some circs I have used inductors and capacitors for a debounce. JR

I know? It sounds like I am a kid. I say it needs an RC and they all think remote controled.

I flew an RC Bell47 helo.

This is not that RC..

This RC is an RC circuit .Yup. Inductors and conductors. RC.. JR

[PStechPaul]

RC is resistors and capacitors, which may be connected in series across a relay coil or contacts as a snubber. The capacitor provides a path for the current from the inductance when the circuit is interrupted, and the resistor serves to dissipate the energy.

I think what was needed was hysteresis, which could be solved by using two float switches and relays as shown above.

[wmgeorge]

I am hoping he got the drain fixed by now and does not need a pump. Sounds like he had a real problem and I hate drain issues.

[Cenedd]

I am hoping he got the drain fixed by now and does not need a pump. Sounds like he had a real problem and I hate drain issues.

I was hoping that too....but not yet. Tomorrow afternoon they should be attacking the problem from the manhole side - now that we've found that. That should mean that we can dispense with the pump and it should be enough to drain the washing machine - which is connected to the same line - without having to pump that out the toilet bowl. We will still need to dig up the (new!) kitchen floor and a good chunk of garden to reconnect the toilet to the correct drain and cap off the existing one now that we know that it is not suitable. The only reason it isn't suitable (apart from the fact it is at least partially blocked) is because it joins rain water drain before it gets to the manhole. Otherwise it should have been fine. We'll get there....just not quickly unless I want to throw big wodges of cash at the problem.