Circuit Diagram critique appreciated

[swanwick]

If you have a ball valve or other metal fitting you could use that to "ground" the cooler MLT.

Gotcha, so if I run a 14gauge wire from my ball valve to my brew tree (metal) that should work, right? I already have the 12vDC transformer so I might just use that for the float switch anyway even though bunch of people said not to worry about it. Not sure I want to deal with using the power from the fan power source because it is currently "downstream" from the float switch.

I am using GFCI power through an extension cord and into the tool box via the male 120vAC. I appreciate people double checking though. I have tried to research a lot, but there is so much I don't know that I don't know.

 

[raouliii]

.... I already have the 12vDC transformer so I might just use that for the float switch anyway even though bunch of people said not to worry about it. Not sure I want to deal with using the power from the fan power source because it is currently "downstream" from the float switch.....

FWIW, the fan power source (wall wart) is the only DC source you've shown in your diagrams so far. What actually is the 12vDC transformer that you have? A simple transformer, such as a doorbell transformer, does not convert to DC.

To clear up confusion, I agree with the others on the float switch voltage. A 12vDC circuit is much safer, since it's in contact with liquid. However, the circuit becomes a bit more complicated. Worth the trouble for safety's sake? Yes.

 

[swanwick]

FWIW, the fan power source (wall wart) is the only DC source you've shown in your diagrams so far. What actually is the 12vDC transformer that you have? A simple transformer, such as a doorbell transformer, does not convert to DC.

heh, I bought it a while back when I knew even less than I know now. Just looked it up and it appears to be this relay (not a transformer) which on the bright side does appear to be a DPDT though I think I am fine with the way I have daisy-chained the pushbuttons.

To clear up confusion, I agree with the others on the float switch voltage. A 12vDC circuit is much safer, since it's in contact with liquid. However, the circuit becomes a bit more complicated. Worth the trouble for safety's sake? Yes.

How dare you make me go back to the drawing board!?! Just kidding, safety first. Any suggs for what I should get to achieve the lower level power for the float switch that will control the relay to power the pump/fan?

 

[evanmars]

Next:

View attachment Schematic.bmp

 

[evanmars]

Note that the way it is shown, if the contacts of SSR short out, the heater will be powered any time the circuit is plugged in. Switch or no, calling for heat or not.

Obviously didn't include a 12VDC power supply for the float switch / relay combo.
Ran out of room with the limits of a .bmp allowed to be uploaded.
Circuit design in Paint is NOT the way to go!

 

[swanwick]

Sorry evanmars, not sure exactly how to read your diagram.

Why do the SSR and CR1 show twice in the diagram?

What is the significance of the two parallel lines on one of the SSR and CR1 items?

 

[evanmars]

Sorry evanmars, not sure exactly how to read your diagram.

Why do the SSR and CR1 show twice in the diagram?

What is the significance of the two parallel lines on one of the SSR and CR1 items?

The circle for the relay CR1 and square for SSR represent the coils for those components. The parallel lines are their respective contacts.

 

[swanwick]

I started the build this weekend. Have most of the stuff installed into the toolbox and started the wiring.

A few challenges remaining

• newbie question: I indicated a 15amp fuse, but they come in little cylinders. What device should I buy to properly wire it into the hot side?
• How to reduce the power for the float switch to 12v?
• What are the best spade connectors to get? The ones I got at Home Depot don't seem to grab the wires well when squeezed by plyers. Is there some trick to that?
• I looked for a wall wart for the computer fan, but I only seem to have computer ones (higher voltage) or phone ones (5v). Wondering if fan will run fast enough at the lower voltage.

 

[evanmars]

Here are some fuse holders on ebay:
http://www.ebay.com/sch/i.html?_trksid=m570.l3201&_nkw=1%2F4%22+fuse+holder&_sacat=0

Some from Mouser
http://www.mouser.com/Circuit-Prote...0z7zwZ1z0z385Z1yzreqpZ1z0z812Z1z0z5fmZ1z0z54q

 

[danb35]

If you're using crimp-on terminals (a perfectly valid choice on stranded wire), you need to use a proper crimper to attach them. Pliers aren't a proper crimp tool. I like (and use) a racheting crimp tool, but an automotive-style tool will do the job just fine.

 

[jCOSbrew]

You could actually send gnd signal for relay coil through the float switch.

+12v ---- relay coil ---- float switch --- GND

The NO contacts on the relay will enable 120v power to pump AND pid output to Ssr. You don't want the element ON while pump is OFF.

The auto/manual switch on your panel would bypass the float switch and provide Gnd to relay coil allowing the pump and element to operate regardless of the fluid level.

 

[evanmars]

But he still has the question of where does he get the 12V from? Is the relay coil 12VDC or 12VAC?

 

[swanwick]

Jcos, not sure I am following what you are saying.

Thanks Danb. I just bought a 145 piece connector set on Amazon. I think it included a crimp tool. If not, will get one.

I have two wall wart power converters.

1. I bought a new one for the fan because I couldn't find 12v
2. It seems that the float switch itself is ok with any voltage, as long as low amps. I have found a 32v power converter for a printer. Does that reduce the voltage enough to be safe?

.

The plug for the printer power converter has holes in the prongs (it seems most plugs do). Can I wrap the 110v power wire within that hole and then cover it up with electrical tape? Do I do the same with neutral for the other prong? Not sure if it is 32v DC or AC coming out the other end. Will it matter for the float switch? Will the DC vs. AC matter for the relay that will send the 110v through to the pump and fan when float is closed?

 

[swanwick]

Added the new wall wart to diagram and added a new wire color for the new 32v that comes out of it.

Do I need to get a special relay that takes 32vDC for the coil? If so, might as well buy a 12v wall wart and use the 12vDC relay that I already have

Also, I realized that the hot for my relay was better to be coming from the NO port on the float pushbutton rather than the pump pushbutton so that like the float wallwart, it is only energized when the float button is pressed.

 

[BadNewsBrewery]

Whatever voltage rating the coil is listed at, that's the voltage that needs to be supplied. So, if your relay is 12vdc, and your supply is 32vdc, expect problems. Option 1 - new relay. Option 2 - new power supply. Either way, the supplied power must be the same as the rated demand.

 

[jCOSbrew]

But he still has the question of where does he get the 12V from? Is the relay coil 12VDC or 12VAC?

My suggestion was to wire the fan AC outlet so that it is "always ON" and use the same 12vDC wall wort for the fan and the relay coil. Keep it simple. Along these lines consider dropping the float switch and relay from your initial build and add it later if necessary.

I am not a RIMS expert (I use eBIAB) but the first time the pump turns off while the element is on you will have a nice burnt/smokey version of your beer recipe.

 

[swanwick]

Woohoooo, just came across a 12v wall wart. Will be using that instead of my crazy 32v set-up. Should work with my DPDT 12v coil relay now even though I only need the single.

Will update diagram when I get back on my home computer.

BadNewsBrewery, just noticed you are in Severn, MD. I'll be in Annapolis this weekend. Let me know if you have any interest in grabbing a beer. I have some American Pale Ale and a Raging Bitch clone homebrew. Would love to see what you are building.

 

[raouliii]

......The plug..has holes in the prongs (it seems most plugs do). Can I wrap the 110v power wire within that hole and then cover it up with electrical tape....

Not a good idea. Just wire up a simplex receptacle and plug in the wallwart. Or as was recommended earlier, use the same 12vdc for the fan and float/relay circuit.

BTW and FWIW: The standard nomenclature/color code for DC is positive/red and negative/black, not hot and neutral. There are no +'s and -'s for AC voltage. Standard color code for 120VAC is Hot/Black, Neutral/White and Ground/Green. It's a good habit to build with standard color codes.

 

[swanwick]

Jcos, if I wire the float switch into the same line as fan which is on all the time, float switch will be on all the time. I only want it on for sparging.

raouliii, have modified the diagram according to your color/naming suggs.

 

[evanmars]

Depending on the position of your button labelled "float", your pump will either run all of the time or only when the float switch powers the relay, correct?
If it is running all of the time anyway, does it matter if the float switch / relay is active?

 

[swanwick]

I don't think it matters to the output because as you point out the hot has another short-circuit route to the pump anyway when float pushbutton is "off", but seemed like bad practice to have something "on" (amps flowing) when it is not being used.

Am I wrong about that?

 

[jCOSbrew]

Based on your diagram, the pump ON/OFF switch will enable 120v power to the pump, wallwort, and the fan. If pump is disabled, so if the 12v wallwort to fan and relay.

If you are bypassing the float switch and using the pump in manual mode then you don't care about the relay state. The relay life is measured in 10k-100k cycles not in ON time.

Check your float switch to see if it is NO or NC and wire the relay contacts accordingly.

 

[evanmars]

The float switch doesn't use any power itself. It is just a switch (like your push buttons). If the "float" push button is not pressed (pump runs continuously) it won't matter if the relay contacts are closed or not, the same amount of current will be flowing to the motor. You will have a small amount of current flowing when the float switch is closed to power the relay coil, but not much, and as jCOSbrew stated, the relay has a life of 100k ON-OFF cycles. No need to worry about wearing it out.

 

[swanwick]

Finished the electrical work this weekend. Ordered some fluid quick disconnects and will be testing out the system shortly. Once it is working, I will publish the build in a new thread.

Thanks to everyone for their help. Will definitely name you in the build thread.