Help with 12V Temp Controller and Motorized Valves

[DENBrewer]

I'm not sure the best place to post this so I'll try it here.

I am building a glycol loop for 3 conicals with internal chillers. My thought was to use the 12v aquarium controllers (Willhi) to actuate a motorized ball valve to open and close glycol lines to individual fermenters. See the schematic below.

I wired it to a usb adapter (5V, 1A) and the Willhi lights up and seems to be working. I wired as shown below (which I think is correct) and I can't get the valve to actuate. I haven't worked with this stuff much and am hoping someone here can help me out. Cheers.

View attachment Glycol Schematic.pdf

View attachment Wiring Diagram.pdf

 

[day_trippr]

So the controller requires 12 VOLTS DC to operate, and you have it trying to run on 5 VOLTS. While the logic circuits may be working by some minor miracle, the odds are the relay coil needs more than 5 VOLTS to switch.

As well, that valve says it needs 9 to 24V for the coil to work, so 5 VOLTS isn't going to hack it.

Finally, your wiring diagram isn't going to work. The valve needs a switched power source - the controller does not provide power to either relay contact - you have to wire that in.

I would wire as follows:

+12V DC to controller pins 2 and 3
DC GND to controller pin 4 and valve "GR" pin
Controller pin 1 to valve "RD" pin

Cheers!

 

[DENBrewer]

So the controller requires 12 VOLTS DC to operate, and you have it trying to run on 5 VOLTS. While the logic circuits may be working by some minor miracle, the odds are the relay coil needs more than 5 VOLTS to switch.

As well, that valve says it needs 9 to 24V for the coil to work, so 5 VOLTS isn't going to hack it.

Finally, your wiring diagram isn't going to work. The valve needs a switched power source - the controller does not provide power to either relay contact - you have to wire that in.

I would wire as follows:

+12V DC to controller pins 2 and 3
DC GND to controller pin 4 and valve "GR" pin
Controller pin 1 to valve "RD" pin

Cheers!

Thanks Day Trppr. The usb was the only cable I had so I figured since the controller said <3W, it might work. I cut off the end of a 12v car charger and wired per your comment and it worked and the valve opened. However, I think I learned that my valve does not fail closed so I had the wrong diagram. I think the right wiring diagram is below. Is there any way to make it automatically close when the temperature reaches the low setpoint?

 

[day_trippr]

Ugh. Any chance you can exchange that valve for one that closes on loss of power - like the CR04 version?

Otherwise, you'll need to add a DPDT relay with a 12V compatible coil to your schematic, in between the controller and the valve. The relay coil would be switched by the controller output (the same way the valve is controlled now), the relay poles would go to 12V DC and DC GND and cross-coupled as when wiring a DC reverse switch, and the switched points would go to the valve coil inputs.

So, when the controller calls for cooling the relay would switch in one direction and the output polarity to the valve would be set, and when set point is reached the controller shuts off its output, the relay coil deactivates, and polarity to the valve coil is reversed.

If you need a diagram for that let me know...

Cheers!

 

[DENBrewer]

I can't return the valves. I may consider getting new ones depending on how difficult (and expensive) the relay is. Something like this seems like it may not be too difficult to wire in.
http://www.amazon.com/dp/B0087ZTH1I/?tag=skimlinks_replacement-20

Also, Do you have any recommendation for a power supply? I'm thinking a 12v, 1 A but I'm not sure. I'm thinking these"
http://www.amazon.com/dp/B00FEOB4EI/?tag=skimlinks_replacement-20

Thanks a lot for your help and advice. If it's too much work, I'll probably just order more valves. Cheers!

 

[day_trippr]

Together, that relay and wall wart would do the job well.

The wiring isn't complex but it does need to be correct. Using the relay to provide a reversible 12V DC/GND connection across the valve coil on command of the controller is the whole game in a nutshell, so if you can picture how that works you're home free...

Cheers!

 

[JohnnyBe]

DENBrewer did you ever finish this project? I'm looking to do the same thing or use 120V ball valves and STC-1000 instead if this didn't work well for you.