mr moab
Posts: 2
Joined: Fri Jan 08, 2016 11:04 pm

Sensing sump pump activity

Fri Jan 08, 2016 11:26 pm

I am working on a project to provide feedback on the operation of a sump pump sitting in a cistern. The primary goal is to be notified if the cistern is full, indicating the pump is not working. I have that worked out by using a float switch and having the RPi send me a text message. Loving that solution!

The second challenge is how to detect each time the pump turns on and off. I particularity want to know if the pump is stuck in "on" state for any extended length of time indicating a potential impeller or output plumbing failure. I have looked at current sensors, but it seems overly complex for my needs. Just wondering if there is more simple way or sensor solution to detect each time the pump turns on and off?

Thanks

ElEscalador
Posts: 697
Joined: Tue Dec 15, 2015 4:55 pm
Location: Detroit, MI USA
Contact: Website

Re: Sensing sump pump activity

Sat Jan 09, 2016 1:26 am

Is the sump pump controlled by an external float? You can just put a relay with a 110 volt coil in parallel with the pump motor and wire the contacts to the pi gpio pin and read that like you read the high water float.
My Autonomous Robot Project and a few of my other projects below.

https://lloydbrombach.wordpress.com/

mr moab
Posts: 2
Joined: Fri Jan 08, 2016 11:04 pm

Re: Sensing sump pump activity

Sat Jan 09, 2016 3:55 am

Thank you for the idea.

Float is integrated and this is a submersible pump, water reaches the top of the pump housing at about the same time the float switch trips. Seems like any relay would need to be submersible.

ElEscalador
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Location: Detroit, MI USA
Contact: Website

Re: Sensing sump pump activity

Sat Jan 09, 2016 1:45 pm

Ahh. In that case current sensor would be the standard and is a pretty easy solution. You could also install a VERY small resistance in series with one of the wires going to the sump pump -(either hot or neutral). Just enough for a 4ish volt voltage drop (just enough to light an LED) that I don't think would hurt your pump at all. Across (in parallel with) that resistor you could put an IR LED instead of a regular LED and at that point, you could use it to trigger a IR phototransistor (tape it all up together in black electrical tape or have them both mounted in a dark box or something) and now you have an optically isolated way to input to the pi gpio. I'd sketch it, but I don't have imgur or whatever is needed to put pics here.
My Autonomous Robot Project and a few of my other projects below.

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BudBennett
Posts: 89
Joined: Fri May 17, 2013 2:45 pm
Location: Westcliffe, Colorado, USA

Re: Sensing sump pump activity

Sat Jan 09, 2016 2:39 pm

There are several posts that relate to what you are trying to do. Take a look at this: viewtopic.php?f=37&t=54024&hilit=250v+pump
It covers both voltage and current sensing. Any circuitry you build/install must take into account possible events (like surges) and failure modes. It is good practice not to burn your house down...

Bud.

anita2r
Posts: 226
Joined: Sun Dec 23, 2012 6:55 pm
Location: Ottawa, Canada

Re: Sensing sump pump activity

Sun Jan 10, 2016 3:07 am

mr moab wrote: ... I particularly want to know if the pump is stuck in "on" state for any extended length of time ...

Thanks
Hi,

Not a pump monitor as such, but ...

There are two failure states:
1. High water level
2. Low water level

Causes:
1 High:
power failure
pump failure
float valve fails 'off'
float valve mechanically stuck below 'on' position
outlet blocked
local pipe failure – water recycling into sump

2 Low:
float valve fails 'on'
float valve mechanically stuck above 'off' position

Potential solutions:
1 Add a high level float switch
If high level float switch turns 'on' create alarm condition

2. Add a low level float switch
either
a. create an alarm condition if the low level float switch turns 'off'
or
b create an alarm condition if the low level float switch is off for more than x seconds

The setup depends on available space in the sump to position a low level float switch and
its on/off levels compared to 'normal' pump operation

Hope this gives you an idea for a solution. I might try it myself having had a sump pump running continuously due to a stuck float switch. Fortunately I was in the house and heard the pump running – by which time the motor was hot and no doubt the 'water lubricated' lower bearing was running dry.

Note:
If you have a sump that dries out in summer for instance, you might have to create software that only enables the 'low level' alarm within a certain time from a normal level condition – haven't really thought that through !

Another thought – install a pump that has an independent float switch. These float switches control a mains outlet / mains socket that the pump is plugged in to. If you add an adapter /cube tap then the float switch can control two (or more circuits). One is of course the pump and the other is home made, feeding a mains (120v or 240v) relay with properly isolated low voltage contacts, which can indicate the main float switch state and hence whether the pump is energized or not.

Regards

anita2R
PS sump = cistern

stderr
Posts: 2178
Joined: Sat Dec 01, 2012 11:29 pm

Re: Sensing sump pump activity

Sun Jan 10, 2016 6:01 am

mr moab wrote:IThe second challenge is how to detect each time the pump turns on and off. I particularity want to know if the pump is stuck in "on" state for any extended length of time
Can you hear it turn on and off? Is there a vibration on a pipe that it pumps water in from or out to?

I was looking at this http://www.seeedstudio.com/wiki/Grove_- ... ion_Sensor for another application and in reading this thread, I thought it might be interesting to consider.

It outputs a logic signal and I don't know how rapidly that changes. But for detecting the flow or vibration from a pump that is going to run for a fairly long span, even if this sensor triggers on random bumps or other things you don't want, you could just filter that out in software, leaving in only the signals that stay high long enough to not be noise.

I can believe there are situations where noise might make this not work, e.g. if you want to listen for the click of a relay but you are getting other bumps and things that might be louder. This is only a digital output. There might be something that operates in an analogue manner that could be used in that sort of case, obviously a microphone being one option.

Slackware
Posts: 131
Joined: Mon Jan 18, 2016 3:45 pm

Re: Sensing sump pump activity

Sat Feb 13, 2016 2:05 pm

no one seems to have mentioned. a flow meter on the pumps output. If pump is on, and no water is being pumped that also is useful information. If water is flowing and pump is not on you could be looking at backup driving water in, or a system that will use vacuum to siphon water once you start the system so you can turn off pump and save energy and will work till air in sump pickup.

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