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Controller wiring diagram

Posted: Mon Sep 21, 2015 6:21 pm
by Steve in TX
Can one of you more electrically savvy membera take a look at my wiring diagram for the 240v controller I plan on building? The idea is basically a K-RIMS like the breweasy, but at a much lower price point and using my existing coolers and kettle. I want to control one element with one SSR and two controllers. One is a PID and the other is basically a PWM with knob and digital display. A three position switch will determine which controller is in use. The switch will control the 120v relay coil leads and the positive control leads from the controllers. My biggest concern is bridging all of the neutral control leads and only switching the positive. I think there could be some cross talk with this. I could add an additional pair of NO blocks to the switch, but I want to try to keep this as compact as possible and already have the two block pairs on there.

I also have two pumps in there too. The first pump is for wort and I have been toying with keying the PID control to that so I don't fire the element without recirculation. I don't think this is a big deal overall as the element would be in the kettle not the grains. The second pump is for icebath recirculation.

I don't have an alarm, but I am edging towards adding one. I like the idea of setting the PID to the strike temp and just below boil temp and walking away. I don't like the idea of the alarm constantly going off and don't care to add an extra switch just for the alarm. Are there any alarms with an integral on/off switch? I looked around and didn't find anything, but figure I would ask. My second though is to mount an alarm inside the enclosure with a switch on the panel. This would keep the panel a bit more tidy.

Re: Controller wiring diagram

Posted: Wed Sep 23, 2015 12:01 pm
by BigWally
I'll email a couple of the electrical gurus and have them take a look.

Re: Controller wiring diagram

Posted: Fri Sep 25, 2015 7:22 am
by captbill
Interesting circuit. I believe that you may need a second SSR to switch the 240 since both legs are hot, you want to switch them both off. Where are you pulling the neutral wire from?

Re: Controller wiring diagram

Posted: Wed Sep 30, 2015 6:43 pm
by Jimmy Orkin
The diagram is hard to follow.

I don't understand the 3 position switch. Is it a double pole three position switch like (pid or regulator or off)? Can you clarify the three position switch and what the different positions are for? What is the point of tying pin 7 of the PID to pin 6 of the regulator?

I think I just don't understand your 3 position switch.

What is the point of the second contactor? What switches it?

If you need the second contactor I would move it to the supply side of the SSR.

I don't know what the normal method of switching 240v with SSRs is. Two SSRs, one on each hot, just adds more resistance (and heat to be dissipated) to the circuit but it might be the convention. I would like to only switch one hot.

Re: Controller wiring diagram

Posted: Fri Oct 23, 2015 11:26 pm
by Steve in TX
Bill - Looking at the diagrams at theelectricbrewery, as well as other 240v BCS builds, switching the single hot with an SSR is normal. I thought it was wrong too, but others have confirmed. The element receives the two hots while the element housing receives the ground. I guess in a worst case scenario this could be bad, but that is what the GFCI at the wall is for :wink: The neutral comes from the 4-wire in.

Jimmy - Sorry it is hard to follow. Here is a better one that incorporates some mods that a buddy recommended as well as better wire traces. I wanted to bring this to the last brewday, but stuff got in the way this time. Let me see if I can explain.

first contactor (right off the 240 in)
Controls power to the entire panel using the switch at the top of the diagram. That switch is powered off of the red hot and Pump 2 (sump pump) is also powered off of this switch to balance the draw across the two legs. The black hot goes to the hot bus to power the chugger pump and all other components.

3-Pos Switch
Center position - SSR is dead, 240v contactor is dead.
Left position - switches the PID positive control lead as well as 120v to the element contactor coil. 120v and both control leads go through the NC side of the 3PDT relay
Right position - switches a coil on a 3PDT relay to the NO side switching the 120v and control leads.

Switching both control leads was recommended to prevent freaking out either controller with signals it isn't expecting. I was originally planning on switching just the positive control lead. The 3PDT could be eliminated by using more switch blocks, but I am worried about the depth of a 3 stack of blocks. I might order the parts to do it without the 3PDT and fall back on that if space is an issue.

I'll bring this to the next brewday for sure. I won't be building it until after the relocation to SoCal and will likely need to grease the purse strings to get funding. I might need to get an 8 gallon kettle and do some kitchen brewing until we can figure out our new much inflated budget. UGH.