Circuit Diagram critique appreciated

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swanwick

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I have been learning WAY more about electricity than I ever thought I would when I decided to take on this project.....

I am building a RIMS tube that will attach to a toolbox and all the electrical stuff will go in the toolbox. 120vAC system. Will use 3 pushbuttons to run: PID/heater/RTD, pump/fan, and float switch (just for sparging). Each of the pushbuttons has 1NC block and 1NO block.

Would love advice on whether I have the attached diagram laid out correctly.

A few specific questions:
  1. I don't think I need any 120vAC negative running from the pushbuttons because the power will be flowing through there to the loaded item and so should complete the circuit further back and then still light up. Is that correct? I am most concerned about far right pushbutton because it is designed to be open when pressed which means there will be no power flowing through it at that point. So, how does it light up?
  2. I also think I have the SSR wiring set up correctly, but not sure. Mostly concerned about the 14gauge portion. Pretty confident with the PID (purple) hookups
  3. Is that the right fuse size (15amps) and placed in the right location? ie. hot side
  4. Is the transformer the right item in the top right? relay? another SSR? Won't be cycling as often as the heater and pump doesn't draw as much power as heater so not sure.
  5. Is the wire gauge selection correct?

Thanks in advance for the help.

Swan Electrical diagram v3.jpg
 
I am assuming that your 120v "negative" is actually neutral.... Depending on the switch if it is illuminated all the time you will need a neutral
 
A few comments/questions:
The current carrying conductors of a 120V AC system are usually referred to as Hot and Neutral, there is no "negative".
The illuminated switches will need a neutral to light up.
The load side of the SSR is essentially a switch. Hot in and a switched Hot out. Neutral must be wired around the SSR to the heating element.
Not sure how the float circuit is supposed to operate. The middle switch powers the circuit and the right switch bypasses the float switch?
The transformer will simply provide 24vac. What is the 24vac for?
 
Thanks so much for the responses.

Sorry, haven't got all the terminology quite correct yet. Yes, I meant neutral rather than negative. I am thinking batteries that have + and -.

Have added neutrals to the pushbuttons. I don't have the pushbuttons in front of me. How do they actually get wired? Is there a hot and neutral on each side for each block?

Have changed the SSR to have neutral go right back. That means that there is nothing plugged into the neutral side of the SSR?

Yes, the middle button powers the circuit and the right button is NC so when off it allows the current through. When on, it opens the bypass and the current flows only when the float switch is closed. The third button will be pressed (open) for sparging and not pressed (closed) for mashing.

I thought the transformer turned 120vAC into 24vDC. I thought that is what I needed for the float switch. What is the recommended way to power the float switch? It is a standard Madison float switch.

New diagram below based on recommendations.

Swan Electrical diagram v4.jpg
 
....Have added neutrals to the pushbuttons. I don't have the pushbuttons in front of me. How do they actually get wired? Is there a hot and neutral on each side for each block?.....
That depends on the switch schematic/diagram.

....Have changed the SSR to have neutral go right back. That means that there is nothing plugged into the neutral side of the SSR? ....
It's essentially a switch. Hot in and switched Hot out, much like the rest of the switches.

......Yes, the middle button powers the circuit and the right button is NC so when off it allows the current through. When on, it opens the bypass and the current flows only when the float switch is closed. The third button will be pressed (open) for sparging and not pressed (closed) for mashing.

I thought the transformer turned 120vAC into 24vDC. I thought that is what I needed for the float switch. What is the recommended way to power the float switch? It is a standard Madison float switch...........
This also depends on the float switch. Is it rated for the voltage and current of the pump? If not, then a relay of some kind will be needed. Model # or specs are needed. A transformer only steps voltage up or down. It doesn't convert AC to DC on its own.
 
Does your schematic show a 29V pump?

The float switch is just that - a switch. Think of it like a push button that the fluid pushes instead of your finger.
If it is rated for the voltage and amperage of the pump, then it just goes inline with the hot leg of the pump.

Are the bulbs in your switches 120VAC?

Schematic for switch to be lit when pressed and power to pump when not pressed:

Switch.JPG
 
Does your schematic show a 29V pump?
yes. Those are the specs on the product description

Are the bulbs in your switches 120VAC?
It seems from the specs that they are. Specs even indicate that they can handle 240, but will be a little bit dimmer with 120

Schematic for switch to be lit when pressed and power to pump when not pressed:
Thanks for that diagram. My goal for the middle pushbutton is power to pump when pressed as well as lit when pressed. My goal for the right-hand pushbutton is power to the pump when not pressed (not lit), power must flow around pushbutton (through float switch) when pressed (lit).

Thanks to the awesome schematic, I feel great about the heating element.

Still not quite sure about the float switch. I re-designed with an SSR in the same way that the heater works, but the PID is supplying power to the SSR in that case. Nothing is really supplying power to the float switch for it to energize the SSR.

Swan Electrical diagram v5.jpg
 
Ok, it's 115v, 0.029kW
Good on the bulbs
Not sure what you are doing with the float switch/SSR. Keeping the pump from running dry?
I'll see if I can whip up a diagram for that when I have a chance today unless someone beats me to it. An SSR isn't necessary for that. A simple mechanical relay would be fine.
 
Post a link to the specs on the float switch you plan to use. The specs on the pump indicate a current draw of less than 300milliamps. 29w/115v=252mA A float switch spec'd for at least 500milliamps of current flow should be able to handle the pump without using a relay.

If you choose to use a relay, the float switch should be used to switch the coil voltage on the relay. The relay can then be spec'd for 500milliamps or more. The float switch would be spec'd to handle the current draw of the relay coil only.
 
Idiot mistake. Yes. 29w 120v for the pump. I thought I read somewhere that it was 1.4amps, but 29/120 = .25amps

Mechanical relay seems to make more sense for the float switch given that it won't switch as much as heater and is not drawing much power through the switch (I think that makes sense).

I have a gravity driven 3 tier system with HLT and boil heated via propane and a cooler mash-tun. I am going to use the float switch in the mash-tun to drive the pump from the HLT through the RIMS tube during sparging. The benefits of this are two:
  1. I can better hit sparge temp precisely by going through the RIMS tube for a "top-up" on temp as needed.
  2. I can match the inflow and outflow rates. The speed of the sparge will be driven by the gravity fed outlet ball-valve on the cooler that leads to the boil kettle. When the fluid height at the top of mash-tun drops enough, the pump (and heater if needed) will kick on until the fluid rises and the float switch goes back up.

I just found some info about how I could hook it up here. Have updated the diagram to incorporate that design. Does this look right?

Swan Electrical diagram v6.jpg
 
crossposted a bit.

Yes, evanmars that looks like the right logical circuit for what I am trying to accomplish. Not sure about the voltage changes for the float switch and how it is powered. I posted a diagram that has a transformer and a relay, but might be overkill. Thoughts?

rauliii here is the link to the float switch spec It seems I need to dial down the voltage as I think I did in the diagram of my last post.
 
Last edited by a moderator:
The switch is just large enough to handle the power, it is rated at 30VA, the pump is about 29VA, but it would be safer to power a relay with it and run the pump through the relay.
I would do away with the 120vac/24vac transformer and just use a relay with a 120vac coil.

What is the fan for? It will be turning on and off at the same time as the pump.
 
You might also consider using a mechanical float switch that will turn pump flow on/off based on fluid level and eliminating half of the wiring. Bilchmann makes one.

If you want the float switch to electrically control the pump use your existing 12v transformer to power the the coil of a 12v relay that controls 120v for the pump. The float switch can be in series w/ the relay coil. You could also replace 2 of the switches with a single 3-way switch which has ON-OFF-Auto mode for the pump.
 
The fan is because this circuit is installed in a tool box to make it portable. The pump has the liquid part on the outside and the motor on the inside. The RIMS tube is bolted to the back of box so that heater/thermoprobe leads can be run from holes drilled in the box. Pushbuttons and PID readout on the top of the box. heat sink for SSR, power input, and fan installed on sides of box.

My thinking was that for mash re-circ when pump is constantly running, the fan would also run along with it to make sure the box doesn't get overheated. Could crack the lid slightly too, but want to do the best I can to keep the liquids out.
 
You might also consider using a mechanical float switch that will turn pump flow on/off based on fluid level and eliminating half of the wiring. Bilchmann makes one.

If you want the float switch to electrically control the pump use your existing 12v transformer to power the the coil of a 12v relay that controls 120v for the pump. The float switch can be in series w/ the relay coil. You could also replace 2 of the switches with a single 3-way switch which has ON-OFF-Auto mode for the pump.

Taking another look at your system description, I don't think you want the element ON when the pump is OFF on a RIMS system. This will scorch the wort. In this case the float switch and relay would have to disable the low voltage signal to the SSR at the same time. You could use a DPDT 12v coil relay.
 
I assume on the "Double Female 120vac" plugs, the neutral connects between the two and thus provides neutral to the other components above?

Did you ever get an answer on how to wire the NC switch to light up when you push it? You'll need to jumper the NC line and NO line side, and then run the NO load side to the LED, and your neutral to the other post of the LED. That way, when you push the button, you open your main circuit, but close the secondary circuit that would allow power to the LED. If you already got that answer and I missed it - my bad.

-Kevin
 
Taking another look at your system description, I don't think you want the element ON when the pump is OFF on a RIMS system. This will scorch the wort. In this case the float switch and relay would have to disable the low voltage signal to the SSR at the same time. You could use a DPDT 12v coil relay.

Yeah I hear you, I have done the requisite reading about wort scorching, but here was my thinking.....
  • I wanted to leave the opportunity to use the pump without the RIMS tube being on (possibly for recirculating water through a chiller).
  • I felt that I could be smart enough to never turn on the first button without the second
  • Idiot thinking to expect that my situation will be different, but it seems the thermoprobe is so close that it would turn off the heater before the wort temp would get out of hand

It seems easy enough to route the power from the output side of the pump pushbutton back to the PID pushbutton so that the PID can only be closed (on) when the Pump circuit is closed (on).

New Diagram:

Swan Electrical diagram v7.jpg
 
I assume on the "Double Female 120vac" plugs, the neutral connects between the two and thus provides neutral to the other components above?

Yes, both of the female plugs will be on the same circuit. I am inexperienced with wiring, but I am guessing that I will run the hot from where they come from elsewhere over to the second of the plugs and then back out to the overall system neutral. The incoming neutrals will be able to go straight to where the output neutral is.

Did you ever get an answer on how to wire the NC switch to light up when you push it? You'll need to jumper the NC line and NO line side, and then run the NO load side to the LED, and your neutral to the other post of the LED. That way, when you push the button, you open your main circuit, but close the secondary circuit that would allow power to the LED. If you already got that answer and I missed it - my bad.

That is helpful. All I understood so far is that I needed a neutral coming out of the pushbutton so that the light would light up. I added those to the diagram. I am now back home so I will inspect the pushbuttons and see if I can understand what you are suggesting.
 
I'm not following the sometimes 120vAC, sometimes 12vDC comment.

The relay control coil will either be AC or DC controlled. If you choose DC then you will need a power supply of some sort that provides 12vDC. The cleanest method is to use a relay that is controlled by 120vAC, fed through the float switch to the coil. No power supply or transformer needed. The coil current will be in the 10mA range, which is easily compatible with the 30VA rating of the float switch. 120V*.01A=1.2VA

As JCOSbrew indicated, a DPST or DPDT relay could be used to turn on the pump and also enable the control signal to the SSR using the second relay contacts. The element would only be ON when the the float switch was happy, if that fits your design requirements. The pump bypass switch can be used to force the pump ON.
 
I would recommend running the fan whenever you have power connected to the toolbox. The SSR can generate a significant amount of heat, probably more than the pump. The Fan should blow/pull air across the SSR heat sink.

I would also recommend using a low voltage signal (i.e. 12-24V DC or Gnd) on the float switch, it is safer. Since you already have a transformer for the internal fan, you have access to 12V DC.

With the number of switches on your current diagram you could provide the following functions:
1 switch for auto/manual mode (disables the float switch function)
1 switch for pump enabled/disabled

In auto mode, the float switch is in series w/ relay coil power (or Gnd)
In manual mode, the switch connects power (or Gnd) to relay coil regardless of whether the float switch is open or closed. The same function could be accomplished which a single 3-way switch.
 
I'm not following the sometimes 120vAC, sometimes 12vDC comment.

Sorry, have clarified by splitting into two colors. The floatswitch circuit is using 22 gauge for 120v and the computer fan and PID have 22 gauge for other voltage. New diagram attached

As JCOSbrew indicated, a DPST or DPDT relay could be used to turn on the pump and also enable the control signal to the SSR using the second relay contacts. The element would only be ON when the the float switch was happy, if that fits your design requirements. The pump bypass switch can be used to force the pump ON.

Is there a reason why my powering of the PID pushbutton from the closed Pump pushbutton won't do the trick? It seems like a simpler solution and gives me the option of running the pump without the PID/heater.

I have a relay that says KLY2 10A 250VAC on the side. Can't remember where I purchased it to find the specs, but I did a google search of "KLY2 relay" and found this. Can that be used either for the float switch relay or (if you don't think my pushbutton wiring will work) for the other relay that you are suggesting?

Swan Electrical diagram v8.jpg
 
If you do decide to connect 120v to your kettle (via the float switch) make sure your kettle is grounded and your have a GFCI power source. The GFCI is highly recommend regardless of the float switch implementation.

The KLY2 series relay will come in several version including 12V, 24v, and 120VAC coil. Check the full P/N on the manufacture site. The 10A @ 250V sounds like the max power rating for the relay contacts.
 
swanwick, if I can make a suggestion: Make your diagram a little more uniform and thus easy to read down the line. For example - rather than label each button as "illuminated pushbutton", put that over in your legend, and then show what each push button will be for (pump, PID, whatever). Also, you show the line side and load side on different sides of your switches depending on which switch you use. Sure, it makes no difference, but it helps to be uniform - then you know all the connections to one side will be your supply, all the connections to the other side will be switched (load). Also, if lines actually connect to each other (jumpered), show them that way. Your left switch shows 3 120vac lines and one neutral all hitting the switch. Are all 3 120vac lines going to the same pin, or are some on the NO and some on the NC circuit? If they're all goign to the same point, just show one line to the switch and have the others tie into it before it gets to the switch.

None of this will actually change the function of the diagram, but it should make it cleaner / easier to read. If you need help, PM me and I'll see what I can do.

-Kevin
 
I would recommend running the fan whenever you have power connected to the toolbox. The SSR can generate a significant amount of heat, probably more than the pump. The Fan should blow/pull air across the SSR heat sink.

The SSR is going to be mounted into the side of the toolbox with the heat sink on the outside. I hear you about turning on the fan when powered, but I am getting fatigue with designing this circuit and so may do that as an upgrade if the box does appear to get hot.

I would also recommend using a low voltage signal (i.e. 12-24V DC or Gnd) on the float switch, it is safer. Since you already have a transformer for the internal fan, you have access to 12V DC.

That does make sense, but several others seemed to think it was going to be fine. Getting conflicting recs.

With the number of switches on your current diagram you could provide the following functions:
1 switch for auto/manual mode (disables the float switch function)
1 switch for pump enabled/disabled

In auto mode, the float switch is in series w/ relay coil power (or Gnd)
In manual mode, the switch connects power (or Gnd) to relay coil regardless of whether the float switch is open or closed. The same function could be accomplished which a single 3-way switch.

I thought about a 3-way switch at the beginning. I ended up going this way because I felt it would be simpler per item and would create the most opportunity for different configurations. Also the three different colored illuminated pushbuttons look cooler. :)
 
120v coil on your relay is fine, just make sure your system is grounded (including grounding the mash tun), and use a GFCI.
That being said, 12VDC is safer still. Still need a GCFI and ground for the 120v running around in the rest of the system.
 
swanwick, if I can make a suggestion: Make your diagram a little more uniform and thus easy to read down the line.

Thanks Kevin. For all the effort that I am putting in and you guys are putting in to help me, I want this to be valuable to people who come behind. I plan to write up a full report once I get through the build.

So, making it readable is important. Is the below better? All pushbuttons now have power flowing left to right. I had the original one with the left button the other way just to avoid wires crossing on the diagram.

HBT won't allow for uploading the .vsd file, but I can email to you if there are things easier to just do than describe.

Swan Electrical diagram v9.jpg
 
OK, I think I am just about finished here. I looked up the specs for the pushbutton and figured out exactly how to wire. There is a separate wiring for the pushbutton light.

The bad news is that it makes the diagram WAY more complex. The good news is that if someone buys the same stuff, they will have pretty exact direction of how to set it up.

Anyone think I am missing anything? You all are fantastic for sticking in with me this far. I really appreciate it. I hope that people end up asking questions about my build so that I can pay it back to the community.

I have a cooler mashtun. Does it still need to be grounded? How does one do that?

Swan Electrical diagram v10.jpg
 
I have a cooler mashtun. Does it still need to be grounded? How does one do that?

Lets say there is an issue w/ the float switch. Your cooler won't be live (because it is plastic) but the water/wort will be. If you stick a metal spoon in to stir than you are the ground, ZAP.

If you have a ball valve or other metal fitting you could use that to "ground" the cooler MLT.
 
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. :)
 
.... 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.
 
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?
 
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!
 
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?
 
swanwick said:
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.
 
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.
 
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.
 
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