Auto Top-Off Schematic?

[fio1022]

I'm looking for a schematic for an auto top off system I'm trying to build.I have two float switches and a relay,not sure how to hook it up.
I want to have the lower float set(min.level) to energize a relay coil and a upper float set(max.level) to de-energize the relay coil.
What i don't understand is when the lower float drops, the contacts close and it energizes the coil.As the float starts to rise its going to open the contacts so how is the upper float ever going to come into play?
I'm thinking a second relay but kind of confused about it.
Any suggestions or ideas how to do this?

 

[Anonymous]

Just make the lower float your upper float.


Ignore for a moment the upper float completely.


As the float drops because water needs replacing the contacts close and the coil is energized. Wallah, water enters and raises the float which open the contacts and ends the water flow.


what did you need the second float for?

Unless its a safety to be hooked up in the same way...

 

[fio1022]

I wanted the second float so the pump would not cycle constanly.There is only maybe a 1/4" of movement before the contacts open/close.
I figured a way to make this work with one relay and two floats.The relay is going to need two sets of contacts.One set will act as a "seal in" to keep pump running until level reaches high float.Second set will turn pump on.
I just have to figure out what pump to get.I was thinking of the Aqua Medic SP 3000 Dosing Pump,but read somewhere that it is too fast for limewater(.8gal/hr).
Is that too fast of a rate?

 

[das75]

1/4" is what volume?

 

[Anonymous]

The safest way to a connect float switch is two wired in series and have them set at the same level. Have them set in the NO (normally open) position. That way both have to close in order for water to be pumped. This is fail safe.

If you rely on a single float switch, it's only a matter of time before it fail and your tank becomes a fresh water tank in a hurry.

With two wired in series, they would both have to stick in the on position for you to get a flood. Not all that likely if you clean them a few times a year.

Louey

 

[minibowmatt]

try these instructions. you may have to adapt them a bit if your relay is different.
http://www.aquahub.com/store/diygaquarium.html

 

[Anonymous]

I disagree with wiring two float switches as shown in the diagram linked above. One float turns the water on and the second on turns it off. What if the second float switch fails to close? You get a flood.

Wire them both in series and you have a fail safe system that would only fail in the unlikely event that both float switch stuck in the on position.

Having said that, the wiring shown in the above link does look to be wired in series. However, in the description it states that the lower float calls the water on and the upper float turns it off. I don't quite get how that works, given the way the floats are shown wired together.

I did only give that illustration a very brief perusal.

Louey

 

[minibowmatt]

Louey, I have them wired exactly like the schematic above. The pump comes on and off with the lower floatswitch, the second (higher) FS is just a failsafe in case the first one gets stuck on. The first float is NO, and the second floatswitch is a NC, so when it floats, it kills power(or vise-versa). I dont know why they say it differently...?

 

[Anonymous]

Excellent, minibowmatt. That'll work then. Allthough I see no reason to have the higher float much higher than the lower one. The higher it is, the more freshwater you get in case the first one fails.

I am glad to hear that it is set up as fail safe.

Louey

 

[minibowmatt]

I have mine about 1/2" above for just that reason. I found that at 1/4" if i got any waves or air burps in the sump, both would fluctuate...