DIY temp controller.

[Katchupoy]

Ok guys... I just built a DIY temp controller instead of buying the RANCO temp controller.

Now I have a question.

I want to use a relay switch that doesnt use power adaptor or any DC volts to power it... is this possible?

is this the one I want?

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=275-217#

thank you.


anyway, right now... I am just using a relay that uses 12 volts on its coil to switch, and it is working great in controlling my fans....

Thank you.

 

[Kensn]

That relay has a coil rating of 120v ac. So if your circuit is designed to send out 120v ac, or line current, like from the wall outlet, then yes this relay will pull in and switch the cotacts. That one also looks like it will take crimp terminals to aid in wiring. If ya want to swing by I have a few spare relays from my project. They have "ears" with holes in them to mount them with screws. Same coil voltage and terminals.


Wait....ummmm...Maybe I should bring you one......

 

[DonW]

Need a little more info on your set-up. Assuming you just want to use it as a switch then its a redundant component. 110v fans do not hard start so no relay needed. If your switching with a solid state component then it is needed and will work fine.

Make Sence?
Don

 

[Katchupoy]

Thank you to all.... Here is what I have...

I have this cheap temp controller designed for water heaters. This Otto 500 Watt heater Controller was bought at Blue Sierra a long time ago for $20.00. This works great, and I dont worry about my heater sticking up.

Now, I can use this same controller to control my fans but the idea should be the power should be the other way around. So when the heaters are ON the fans are OFF. And when the heaters are OFF then the fans are ON. And the only to do this is install a relay....

Fortunately, I have two of these controllers.... And it acts like a dual stage controller.

Heater turns on at 78 then fans turns on at 80.

But the only relay I can find are the DC ones... until I find this one... which should work fine... I hope.

 

[Katchupoy]

Here are some of the cheap temp controllers I found out there...

http://www.aquariuminstruments.com/en-us/dept_77.html
and
JST controllers (scroll down)
http://www.northcoastmarines.com/heaters.htm

and then the rest is taken care of the relays...

I think its a cheap alternative.

 

[Katchupoy]

...

On another forum... they tried to hack one of those cheap thermostats that has digital display... I think those are cool options too... but Im not comfortable in removing those temp resistor from the pcb and making it waterproof by putting a lot of sealants.

With these, controllers, they have sensors already and is already waterproofed.

What do you think?

 

[DonW]

Radio shack has a great relay that works perfectly for that application. Your controller puts out 110v when it wants the heat on. So basicly the relay has a no and a nc set of contacts. When the heat is on the fans will turn off.
I use the same relay to turn the lights on and off in my prop tank. Main tank light go on prop goes off.

Don

 

[Katchupoy]

Yes,thats what I meant... so this relay will work?

http://www.radioshack.com/product.asp?cookie_test=1&catalog_name=CTLG&product_id=275-217

with a coil rating of 110VAC?

Thank you... I will order it right away.

 

[Llarian]

What are you using as the thermostat/trigger here?

-Dylan

 

[Katchupoy]

Hi Dylan, links is on page #5 (scroll up)
Im using the first one which is the OTTO

 

[Katchupoy]

Diagram...

Ok guys, here is the diagram... so everybody will understand it better.

 

[Kensn]

Either I am missing something or you should be able to plug the fans directly into the output of the thermostat. If you are trying to isolate the fans from the thermostat then that will work, but unless the fans are drawing a whole bunch of current, just plug them in the thermostat. Is there a rating on the thermostat that shows amp rating for the contacts?

 

[Llarian]

Oh, I see what you're doing. You basically want to reverse the signal from the controller.

I guess that makes sense, although you'd think there'd be some cheap little boxed device to do that, although I can't think of one offhand.

-Dylan

 

[Katchupoy]

Ken, Dylan is correct... I just want to reverse the signal.... I want to open the thermostat... but Im afraid I wont see anything that I can play with...

But since this will work " I think " .. I will try to open/crack the thermostat later....

Dylan, the cheapest out of the box is the RANCO controller.... but thats $80.00

 

[Kensn]

Duh.... I should of seen that, I am so use to looking at isolation circuits it didn't pop out at me. The relay I have will suit you fine. You don't need to interupt both the hot(black) and neutral (white) wires to the fan though, just the hot (black) wire. I'll show ya tomorrow !!! No need to crack the thermostat open. We can make a tidy little circuit for ya.

 

[Llarian]

Huh? No, I meant some cheap device to reverse an AC signal. Well, not that AC relays aren't cheap. Use the cheap Otto controller and just run it into a little cube that reverses the signal. Sadly, searching for AC inverter is a lost cause. =)

Anyways, if you can find it, you want a DPST AC relay I believe, not a DPDT, although I suppose you could make that work by just having one set of outputs unused.

-Dylan

 

[Llarian]

Oh, right. Nevermind, my turn for a Duh moment. You just need an SPST AC relay to interrupt one side of the circuit.

-Dylan

 

[Kensn]

Yep and I got one for him in my hot little hand.......well it's a spdt...but a nice encapusalted one with dog ears for mounting and spade terminals.....And free is good!!!

 

[DonW]

This is what you are looking for. This was one of my ideas a long time ago. Worked very well, may still be in my junk box if you want it.
http://www.reeffrontiers.com/forums/showthread.php?threadid=3749

Don