DIY ATO dual float switch with relay

[Tooboot]

Hi,

just looking for some advice in wiring and setting up an ATO with dual float switches using a relay.

I've read a number of posts and viewed some videos, but haven't found anything with a dual float switch and relay, where I don't have to cut the power cord for the pump.

here is a list of the equipment I purchased for this project.

- 2 basic float switches (ebay special) plus a spare in case one doesn't work
- float switch mounts
- 12V DC relay
- 12 V DC plug/converter
- extension cord (to not have to cut my pump power cord)
- aqualifter pump
- airline tubing
- Project box (to try and keep things like the relay dry)

I am looking for either some wiring advice or a link to some other thread/video where someone has done this and the wiring is clearly identified. I am sure there is something out there but just can't find it.

Thanks,

 

[fishgate]

How much have you spent so far? You can get a JBJ dual float ATO for under $70 shipped.

 

[mcgyvr]

 

[Tooboot]

Thanks for the quick reply.

total spent so far is probably close to 30$ with the pump. given I live in Canada the 70$ goes up quite a bit with the exchange and shipping. plus I've been enjoying the DIY part of this hobby so far (still working on my lights).

 

[Tooboot]

is it necessary to have the Diode, or can I skip that.

 

[mcgyvr]

Flyback diode is recommended but not 100% necessary for this application..
A regular 1n4000 series works just fine..

 

[Tooboot]

Thanks all.

I plan on giving this a try tonight. will take some pictures and test things out. if I have any issues, you can be reassured that I'll be reaching out again.

my alternative was to only use the one FS, and a timer to shut the whole thing off for a set period of time as a precaution. the downside to this approach was that I would/could still be faced with short cycling of the pump, and much prefer the diagram that was provided (you read my mind).

Thanks again.

 

[uncleof6]

The flyback diode is not needed for the circuit to function. However, it is a protection circuit. It is intended to provide a safe path for current due to the voltage spike created when an inductive load is suddenly disconnected from its current source. The diode allows the inductor to draw current from itself ("flyback") in a loop, till the energy is dissipated by resistance in the wire, the diode, and sometimes a resistor (.01ohm) as well. The voltage can easily hit 400v - 600v. Such voltage can destroy things like transistors, but can also cause an arc in a switch, and destroy it.

Considering it does not take much to kill a float switch, flyback protection, though not necessary, is a good idea.

Also, you need to remember that there is no failsafe in this circuit. Though it is the most reliable control circuit, there still needs to be a backup plan. The backup plan should be mechanical, not electrical. If you use an electrical failsafe, it would still need a redundant mechanical failsafe. You will want to protect against overfilling, but also protect the ATO pump, and your main return pump against running dry.

 

[Rybren]

Here's a link to the Aquahub site with instructions on how to build the ATO.

http://www.aquahub.com/store/media/TopitOffKitPremiumInstruxCompDec07.pdf

 

[Tooboot]

Here's a link to the Aquahub site with instructions on how to build the ATO.

http://www.aquahub.com/store/media/TopitOffKitPremiumInstruxCompDec07.pdf

Had seen this before and was searching for it again. Thanks, it's what I was looking for.

Now my question is can I combine the two? Essentially set my on/of water level using 2 x FS as suggested by mcgyvr , while adding a back up shut off as in the link. I also learn better with the actual pictures than electrical diagrams (still kearning), but appreciate being able to compare bothave to increase my ability to understand the diagrams.

 

[uncleof6]

Had seen this before and was searching for it again. Thanks, it's what I was looking for.

Now my question is can I combine the two? Essentially set my on/of water level using 2 x FS as suggested by mcgyvr , while adding a back up shut off as in the link. I also learn better with the actual pictures than electrical diagrams (still kearning), but appreciate being able to compare bothave to increase my ability to understand the diagrams.

Why would you want to do that?

Aquahub is an excellent example of how not to build an ATO. Good place for components perhaps. Wire nuts, stripped wires wrapped around screws, tapping into a power cord, all examples of the poorest practices there are.

There isn't any point to combining the two. The latching circuit is the more reliable of the two, which essentially accompish the same thing. In a sense, you can get some guidance from the pictures for component identification, but since the float switches are wired in series, the low FS will cycle excessively, consequently cycling the pump excessively, and the upper FS may or may not ever see use, as it is a high water level failsafe.

I and others appreciate that many cannot read a schematic, or wiring diagram. However, for playing with electical/electronic stuff it is an essential skill. Schematics being the harder of the two. For those that express a lack of skills, I strongly recommend they find someone local that does have the skills, to keep them out of trouble. Skillset includes stripping wires, splicing wires, soldering, crimping connectors, interpreting component pinouts, reading simple wiring diagrams, and knowledge of what is reliable or safe, and what isn't. The money is in the last, like 5 bucks for turning the nut, $10,000 for knowing what nut to turn... It isn't rocket science though, and with a little time, it can be learned.

http://reefcentral.com/forums/showpost.php?p=24720065&postcount=11

 

[Tooboot]

Why would you want to do that?

Aquahub is an excellent example of how not to build an ATO. Good place for components perhaps. Wire nuts, stripped wires wrapped around screws, tapping into a power cord, all examples of the poorest practices there are.

There isn't any point to combining the two. The latching circuit is the more reliable of the two, which essentially accompish the same thing. In a sense, you can get some guidance from the pictures for component identification, but since the float switches are wired in series, the low FS will cycle excessively, consequently cycling the pump excessively, and the upper FS may or may not ever see use, as it is a high water level failsafe.

I and others appreciate that many cannot read a schematic, or wiring diagram. However, for playing with electical/electronic stuff it is an essential skill. Schematics being the harder of the two. For those that express a lack of skills, I strongly recommend they find someone local that does have the skills, to keep them out of trouble. Skillset includes stripping wires, splicing wires, soldering, crimping connectors, interpreting component pinouts, reading simple wiring diagrams, and knowledge of what is reliable or safe, and what isn't. The money is in the last, like 5 bucks for turning the nut, $10,000 for knowing what nut to turn... It isn't rocket science though, and with a little time, it can be learned.

http://reefcentral.com/forums/showpost.php?p=24720065&postcount=11

I am learning and I think for the most part I can make sense of most components in schematics (i.e. the diode). Although from research i'll agree with you that the latching circuit is better, just wanted to add a failsafe (best of both worlds). I must disagree that the aqua hub model is not a good example, some of the other suggestions/threads read are much worse (no relay, cut right into the pump wires...), I was proud to think that at least I was using a relay and and extension cord.
I guess I'll keep toping off with the pump and a timer for now, until my ability to read schematics improves. Otherwise, you could explain what nut to unscew.... and help me learn (take the schematic and put it in lamens terms. Your last post just tells me not to combine and why skills lie in reading schematics.

 

[Tooboot]

You had me determined to understand and I spent the morning researching. Now I understand the simplicity. I take doing rings right very seriously and don't want to let in that I am looking to take shortcuts, hence the earlier frustration, I appreciate the help and the push you gave me to learn something new

 

[OllieNZ]

You had me determined to understand and I spent the morning researching. Now I understand the simplicity. I take doing rings right very seriously and don't want to let in that I am looking to take shortcuts, hence the earlier frustration, I appreciate the help and the push you gave me to learn something new

Here's a quick diagram based on the latching ATO circuit. It uses optocouplers to isolate the float switches from the relay. That should further enhance the life and reliability of the switches themselves, you can get optocouplers that will run on milliamps at a couple of volts. You could also replace the DC pump with an AC pump as per the original.