Pool project: back flow current

The main question is - Is there a risk of current or 110v voltage flowing back to, and destroying delicate components?

Here is the setup. I want to convert a chlorine pool to a salt pool. I need to wire the chlorinator in a way that it stops running, should the motor stop running (I've to take this into consideration as this has happened before.) Pool starts running say 8pm, it's turned on by a Sonoff wifi switch 1, (wired to a 110v relay that turns on the motor.)
Sonoff 1 is timed to start pool running at 8pm, followed by Sonoff 2 (this shuts off within 5 minutes of => .) motor starting to run, water flow closes flow switch, after timed delay voltage from Sonoff 1 is now pathed to Chlorinator, which starts running and current proceeds to join the line from Sonoff 2 to the motor.

Question 1-
Is there any chance of this current flowing backwards towards Sonoff 2 on the output side? If that is so then I see that unit getting fried. What can I do to prevent this?
(Sonoff 2 shuts off after timed shut off, allowing flow switch to shut off pool if there's no water flow.

Question 2-
When the two Sonoffs start and chlorinator is waiting say a 5 minute timed delay before it turns on is there a risk that voltage will flow towards chlorinator and start it, bypasing flow switch? This may not be ok as chlorinator runs on 110v anyways.

 

Since this is Alternating Current, the polarity (including current) reverses 120 times a second. In your diagram, whether electrical or process control, switch 2 appears to serve no purpose.

 

I needed switch 2 in order to make the setup a self start, self holding system, that can shut down the pool, should there be no water flow by opening the flow switch and that will cut off power supply to chlorinator and pump motor. While Switch 1 starts the system I needed to isolate the chlorinator so that it's not inline with the pump, that way there can be a way to trigger it to shut down. Thus, switch 2. only acts as a current conduit for the motor for a minute or two, once the pump is running and flow switch closes switch 2 turns off and current flow is now on the lower loop.

This is where my concern was if back flow current will fry switch 2 via it's output after it shuts down. But what you are saying is AC current reveres anyways and so my concern is moot, or do I need to install a diode here? If so, which type?

 

Sorry.... I'm not following your logic there but I can tell you if you want a 100% shutoff if the pump fails.... you can't use any electronic switches. The motor could fail and your system thinks it's still running. It doesn't know any better. Install a pressure switch in the pump return line. It can be as simple as a form C switch (N.O. - N.C.). The switch needs positive pressure for the chlorinator to work.

 

Not sure what you want, but as I read the drawing Sonoff 1 (S1) will turn everything off
S2 does have no function as long as it is bypassed by the wire under.
If we cut that line under, and move the S2 as showed here.
You may get the pump running as long as S1 is on, The S2 will power the rest as fast as it connects to the wifi, and get signal to run. Then it will close down the chlorinator and valve when it goes in off position. S1 may stop all of it. Not sure if that is what you wanted.

S2 moved

 

What I am looking for is for flow switch (FS) to shutoff Chlorinator (CH) and pump if there's no water flow from the pump. FS will switch a 24vac coil relay that will power CH (110v 2 amps.)

I have no idea how to wire this relay and I am looking for an ELI5, I can't seem to grasp utube vids.

 

This is a lil'bit of a learning curve for me but if you will, I understand coil power is via pin 7 & 8. Which pins do 110vac go into and out after coil is energized? Heeelp :-o)




BTW here is the flow switch I am using. You are saying a pressure switch is preferable?
I plan to splice the 24vac supply that is to energize coil and connect this inline. Water flow will close this switch, which will then power the coil, closing relay contacts for the 110v power to the chlorinator.

 

That flow switch is fine. I think I recommended that to you a while back.
That relay is two form C switches.
C1= common1 (5) , NO1= normally open 1 (3) , NC1= normally closed 1 (1).
C2= common2 (6) , NO2= normally open 2 (4) , NC2 = normally closed 2 (2).

I picked the normally open switch 2 contacts. When the relay is powered those contacts will be closed.

 

Coil energized ok but I am not getting correct output voltage at pins 2 & 4. With 110v connected at pin 2, I tested it with pin 4. I got 3.17v...3.693. Next was Pin 2 & 6, that was 0 to 0.0034.
I tested again with a 24vac live wire and got the same result.
Coil is energized by pins 7&8.
I swapped to pins 1,3,5 and still got the same result.
Does this point to a bad relay unit?

 

I am trying to decide where to position the chlorinator cell (CC). Ideally it's the last item before the water flows back into pool. But looking at my setup here, seems I have to reposition owing to pipes being too close and limiting space. Secondly, I think I don't quite follow the manifold 5 ports. I can see two pipes attached to the filter, must be in & out. At the manifold, I see what I assume to be port out to filter and port back from filter, the other 3 I can't make headway.
Heater failed during a freeze, cracked leaks water. For now I just installed a u connector to bypass heater and keep the pool running. The water coming back from the heater seems to be sent back to the manifold. That's why I am thinking of positioning the cell on the left pipe near the pool heater. I am fairly confident this is where I should install the cell & flow switch. Any ideas guys?








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I am thinking of using a hvac contactor instead of this unit seems delicate. This is the one I am looking at since it has 120v line, most of the others I am seeing are rated at 240/277/480vac etc. Those cannot be used on a 120v line for this setup, correct?

Is this the correct one here? Any ideas on the piping question above?

 

About this item

• 2 Year Replacement Policy
• 40 FLA Amp Rating - 2 Pole - 24 Volt Coil. Replaces Most 2 Pole Contactors ...

 

Sorry but I don't follow.
I don't have good electrical knowledge other than rudimentary understanding but I am able to follow your directions as the expert in this field. Will the contactor above be a good one for this project?

 

You want to use that contactor for the chlorinator ??
No.... you don't want that there.

Go back and look at the picture in post 8 again. I redrew it for you.

I'm guessing the heater is not working and has been removed from the circulation loop ?
Light blue is water into the pump (suction).
Medium blue is pump out to the selector valve.
Dark blue is water out of the selector valve (return) and supply to the heater.
Purple is water out of the heater and back to the pool.
If you intend to reconnect the heater... the chlorinator must be in the purple line.
You can't run the chlorinator into the heater.
I also see a valve in the purple return line to the pool.

I drew the red circle for the flow switch but it can go just about anywhere in the return system.

 

Thank you thank you, thank you, for the flow diag. It's the waste pipe that had me stumped. Urgh. Now everything makes sense. I will position chlorinator on the purple line and the flow switch right after

OK I will skip the contactor. I followed post 8 diag, but I am not getting a 120v output. Even with a different base. That's why I thought to switch to a hvac contactor. I have replaced one before, repaired pitting on another and restored unit. That's why I thought don't they do the same job as a relay? In any case for my learning, what is the electrical reason that it's not usable in this case, to power the chlorinator, even a single pole would not be recommended?

 

I brought this into the garage and made this rig. I am just getting a barely 2v output still. Switched the bases and still the same result. Checking voltage at 2 & 6 is showing 120vac but when it's turned on there's only 1.8vac at 2 & 4. I switched to 1,3,5 and it was the same result. Think I need another relay.

 

A little more details on first pic above

 

Ladies and gentlemen, we got him! The relay diag shows-the wiper swings between 2 & 4, therefore 6 is the common pole. Thus,
6 is common.
2 is NC
4 is NO

Moved the 120v wire to 6 and 4, energized 24v and boom 120v was on at the power strip. Worked flawlessly.

 

Wow.... my mistake. I had the C and NC reversed.

 

No sweat. Thanx to you and everyone else, I now know more about this little relay than before. Project is coming along great, just have to clean up the install for a prof. look.