Need relay to turn on dosing pump for H2O2 injection into well water system

[Jim Goodman]

View attachment 63572 View attachment 63572 OK, here's the story: My water is supplied by a well. I have a water softener and 2 backwash filters on the system to treat the water. I did all the installation, so I'm knowledgeable about the system. Those filters and softeners do a good job of treating the water, but we also have sulfur smell problem with our water. To remedy that problem, I bought a hydrogen peroxide injection system to inject a metered amount of H2O2 into the water flow after the pressure tank. This oxidizes the sulfur and removes the smell. There is a 15 gallon tank that I will with a diluted hydrogen peroxide solution. There is a small diaphragm dosing pump that is attached to the top of the peroxide tank and it has a tube coming out of it that is connected to the house water piping and injects the peroxide solution into the water flow. The pump runs on 120 voltage. Then, I have a flow meter installed after the pressure tank and before the backwash filters. This flow meter has a reed switch that is part of it that sends very low voltage signals to the dosing pump when water is flowing through the flow meter....for example, when you turn on a faucet in the house. The dosing pump has a connector plugged into it that receives this signal, and there are electronics inside the pump that are supposed to trigger the pump to stroke 3 times per gallon of water flowing through the flow meter. This makes the pump a proportional pump that increases the number of strokes per minute depending on the volume of water flowing through the flow meter. So, for example, if you have one sink faucet on, it will pump 3 strokes every 15 seconds or so. But, if you have a couple of sinks running and the shower running, then it should pump 3 strokes maybe every 5 seconds, etc. The number of strokes that the dosing pump pumps per gallon of water was programmed by me, following the directions of the manufacturer, and the number of strokes can be programmed up or down.

My problem is that the pump loses the program and does not pump proportionally. Once you turn on the water....even just a bathroom sink faucet....or flush the toilet, the pump takes off and starts pumping non-stop, regardless of the volume of water running through the flow meter. So, I'm burning through 15 gallons of my peroxide solution every couple of weeks, where it should be lasting me a couple of months, based on our typical water usage. Now...the dosing pump also has a manual setting, and when you put it in the manual setting, you can set it so that it pumps 3 strokes, every 15 seconds, or some other time interval of your choosing. The only thing is, that when the pump is plugged into the wall receptacle, and you have set it in manual mode, it starts pumping that 3 strokes every 15 seconds, for as long as it is powered on, regardless of whether you are using water or not....it just starts pumping to that interval, and keeps pumping.

OK, that's the background. Now, one other thing....the pump is designed to be turned on and off repeatedly, without damaging the pump. So what I want to do is have the pump power up, in manual mode, only when water is flowing through the flow meter, and then power off when water is no longer flowing. I'll lose the proportional feature, where the pump strokes increase in frequency when more water if flowing through the flow meter, but that's a compromise I can live with. To implement this new strategy, I want to use a relay to turn on power to the pump (and the pump would be in manual mode) and have that relay activated by the reed switch that is in the flow meter.

This is where I need help from the forum members. I can do basic house wiring....receptacles, switches, run new circuits to the panel, etc., but I have no idea what kind of relay I need to use or how to hook it up to the power going to the dosing pump. The pump is plugged into a conventional GFCI receptacle.

QUESTION 1: Do I make up some kind of j-box that contains the relay and has a cord coming out of it with a male plug end on it to plug into the GFCI receptacle, and then have another short cord with a female cord end on it to receive the male plug from the pump so the pump is actuated by the relay?

QUESTION 2: When I was trying to troubleshoot the original problem, I took a volt meter and put it on the wires coming from the reed switch and it registered 0.001 volts when the switch fired. So I'm guessing the relay would need to have enough sensitivity to be triggered by that voltage, is that correct.

QUESTION 3: Any advice on the relay to use and how to wire it up would be greatly appreciated. If what I suggested as a setup in QUESTION 1 is a good idea, please let me know. If it's a bone-headed idea, please also let me know. I don't even know what the relay would look like, or how big it would be, so I'm clueless on how to set this up.

I've reprogrammed the pump dozens of times, and it works as it should for 20 minutes and then loses the program. I give up. It's too late to return it and it was $300-$400. I want to try this idea. Any help would be most appreciated. Thanks!

 

[Bannerman]

Suggest posting this topic in the Water Softener forum. That forum often addresses many water treatment methods, equipment and configurations in addition to Water Softeners.

 

[Sponsor]

 

[Reach4]

My problem is that the pump loses the program and does not pump proportionally. Once you turn on the water....even just a bathroom sink faucet....or flush the toilet, the pump takes off and starts pumping non-stop, regardless of the volume of water running through the flow meter.

That is a major failure. I don't suppose there is a backup battery to keep the memory.

So you are saying that you can see a setting on the display, but some amount of time later, that setting has reset to whatever it comes up with when first powered up?

QUESTION 2: When I was trying to troubleshoot the original problem, I took a volt meter and put it on the wires coming from the reed switch and it registered 0.001 volts when the switch fired. So I'm guessing the relay would need to have enough sensitivity to be triggered by that voltage, is that correct.

Looking at the output of the relay, I would think that an Ohms setting on the meter would be the right way to characterize the output of a relay. That is to say, I suspect the sensor just provides a dry contact, and the voltage is provided by the proportional pump. Were you measuring your voltage with the sensor isolated, or wired up to the pump?

I located your pump, and did not find much info on UPC 758576892641

Is there a configuration or setup manual?

Also, is the flow sensor powered separately? If not, it would be up to the pump to supply the current. You may need to set a jumper or something to make that work.

But still, forgetting settings means bad pump... gotta return to that.

 

[Jim Goodman]

So you are saying that you can see a setting on the display, but some amount of time later, that setting has reset to whatever it comes up with when first powered up? - Yes, that's exactly what happens. This is the second pump they sent me too. I got it from an online water treatment company. I've dug around online and the pump comes from China and as far as I can tell, the online water treatment outfit I bought it from is the only one in the US using this particular pump. Bottom line is, I got burned with this thing. The configuration manual is in a Chinese interpretation of English and is unintelligible. The flow sensor is a simple mechanical flow meter with the water passing through spinning a little water wheel inside that causes little dials to spin on the face of the meter. There is no power to the flow meter, and you are right about it just providing a dry contact. I've had some other folks on another forum come to the same conclusions that you have come to. The pump does work in what they call manual mode. In that mode, you can set a time interval for the pump to pump 1 time, and that function is working properly. Right now, when the thing takes off and starts pumping, it is pumping 100 times per minute. So, in manual mode, I could set it to pump...say....once every 10 seconds, and as long as it has power, it will keep pumping at that interval. I now think my goal when I started this thread, of using a relay activated by the reed switch on the flow meter as a workaround to the defective pump that would still achieve proportional dosing, is a waste of time, based on points you and others have brought up. I think I'm going to try using a flow switch to turn on the pump when water is flowing and then just jigger around with the pumping interval in manual mode until I get the right amount of peroxide injected to remove the sulfur smell. Thanks for your help.

 

[Reach4]

One possibility is to move the injector before the pressure tank. Then run the peroxide pump whenever the well pump is pumping. That will be a fairly consistent flow rate from the well pump. Proportional is more sophisticated, but sophisticated is not working.

 

[Jadnashua]

I question whether the measurement you made across your switch is meaningful at all...think about a switch, it just connects two leads together, so in a perfect switch, there would be NO voltage across its contacts when it is closed! You need some reference to measure the voltage into the switch and that would likely be ground, but may not be...

A similar issue is what is the current capacity of the reed switch's contacts and where the return point for that voltage is. Once you know what that voltage is and how much current the switch can provide, then you can figure out how to sense when the reed switch is closed and make that information do something for you. A typical reed switch's contacts often cannot handle much current, so you'd need some sort of sensor to then trigger another, more powerful device to turn on.

So, need some info on the actual switch and what voltage it is turning on/off that does its thing.

Another way to do this may be to add in a separate flow switch that is capable of handling the current needed to activate a relay. That could use something like a 24vac door bell transformer, and any relay for say a heating system for its coil (activation) circuit. Relays have both a rating for their coil and another for their contacts. There are solid state relays that may end up longer-lived.

If your system is not electronically protected, I'd want to install some surge suppression, and maybe consider powering it with a small UPS which not only does that, but also would keep it running through a power outage.

Maybe if you posted a functional block diagram of what you have now, it would be clearer about how to best approach this.

 

[Bannerman]

The meter you describe in post number 1, sounds as though it may utilize a Hall Effect transducer to produce an electrical pulse each time a magnet passes a coil of wire. The magnet(s) would be located on a turbine within the water path which will spin as water flows through it. The number of pulses will relate to a specific quantity of water passing through the turbine.

Hall Effect meters are commonly utilized in water treatment, which is why I had suggested posting this topic within the Water Softener forum. There is an active WS forum participant 'Ditttohead' who designs and sells water treatment equipment. I anticipate he may be able to offer further suggestions on methods to remedy your proportional dosing issue.

Recommend including some photos of your equipment.

 

[WorthFlorida]

With these two devices you may be able to build your own trigger circuit. The question is what are you getting from the sensor? If it is a small pulse caused by a magnetic and reluctor you'll need to find or build a circuit. It's awfully hard without Radio Shack around anymore. A latch relay could work but there is no reset signal to open the relay. I search on Delay Relay and this popped up. http://timers.shop/

You can go the the USA manufacturer's website for this device. It's a timer that once triggered it can delay the open (off). Use this to drive the Functional Device relay. Use a 12v DC plug it transformer and it can power both devices. Besure to use the center tap on the relay primary. This timer, FAQ section, one it gets a pulse it will close the circuit until the end of the timer setting. if another signal is present, it restarts. If no signal, keeps it off. The big question is at the switch location where or how it would be connected to the flow device.
https://www.amazon.com/Timer-Delay-Relay-Cycling-Trigger/dp/B01HNDOCKK?ref_=fsclp_pl_dp_3

This relay is the "load" for the timer, the load on the relay is an AC outlet for your pump motor.
https://www.functionaldevices.com/products/building-automation/details/RIBU1C/

Maybe you can replace your flow sensor with this. It be easy to use this as the switch for the timer circuit.
https://www.amazon.com/DIGITEN-Sens...ocphy=9053023&hvtargid=pla-492368391549&psc=1

https://www.amazon.com/Adapter-100-240V-Transformers-Switching-Adaptor/dp/B019Q3U72M/ref=sr_1_5?crid=UM0A1F3NPFWX&dchild=1&keywords=12v+dc+adapter&qid=1592186226&sprefix=12v+dc,aps,171&sr=8-5

I just purchased the Functional Relay for a project I completed last week. Very well built. If you are not sure how to set this up, give me a day to draw it out. This is how I used the relay. I added LED strip lighting in my pantry closet and the only nearby power was the wrong end of a 3 way light switch circuit.