need help wiring eherms rig

I wish I was handy and smart enough to post pics of my rig after it was done but, alas, that is not to be. I need help from some of the resident pros to figure how to wire this thing and precisely what parts I need.

So, I plan on a three vessel system with two 5500 watt elements - one in the brew kettle and the other in the HLT. I have a pump to circulate the wort in the mash through a copper coil in the HLT. I have a 50amp breaker, a spa box (gfci) for the 240v, and some romex wiring that I'll be installing that this weekend. That's about as far as I've gotten.

The plan is to order an auber pid (SYL-2352) and use 2 RTD sensors 1 in the HLT and 1 in the brew kettle (link http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=85 ) with a DPDT switch to toggle between the two. I've found a nice simple wiring diagram by P-J but I'd like to do things a little differently. Wiring diagram at https://www.homebrewtalk.com/f170/simple-eherms-following-pjs-diagram-w-only-1-pid-221403/

First of all, I see that diagram calls for a single ssr and I think I need to use 2 (one for each leg) to fully open the circuit, right?. I mean, if you only open one leg of the circuit via SSR the element is still on and heating (granted at 1/4 the wattage, but still).

The big complexity, and I can forego this if it is too much work and do it manually, is that I'd like to be able to use the pid to control the pump during chilling. My plan is to use the HLT as an ice bath and pump the wort through the coil until the set temp is reached. During the mash the pump will recirculate constantly so I need an easy way to switch what the pid is controlling. I have yet to buy the pump and was thinking chugger - can I run that or the march at 220? I think that would greatly simplify things.

I can solder and what not but I am far far far from an electrician and am definitely in over my head here. Help.

Sidebar: when shopping for SSRs, I've seen that on Auber's site a 40amp "contactor" is $18 but the 40amp SSR is about the same price. I thought contactors were a bit more heavy duty, is there a reason I should prefer one to the other?

contactor:
http://www.auberins.com/index.php?main_page=product_info&cPath=2_31&products_id=164

SSR
http://www.auberins.com/index.php?main_page=product_info&cPath=2_30&products_id=30

edited to say: I'm stupid. The element won't be hot (warm) with 1 ssr, it will just have a live wire. This seems like a non issue since I also would have the mechanical kill switch, right? I guess the other possibility is that the SSR would fail closed but since I'm always around watching this too is a non issue. Worst case scenario the temp in the HLT spirals out of control and I boil the mash, right?

Lost said:

The plan is to order an auber pid (SYL-2352) and use 2 RTD sensors 1 in the HLT and 1 in the brew kettle (link http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=85 ) with a DPDT switch to toggle between the two. I've found a nice simple wiring diagram by P-J but I'd like to do things a little differently. Wiring diagram at https://www.homebrewtalk.com/f170/simple-eherms-following-pjs-diagram-w-only-1-pid-221403/

Click to expand...

RTD sensors have three wires on them. You will need a 3PDT switch to be able to flip back and forth.

Lost said:

First of all, I see that diagram calls for a single ssr and I think I need to use 2 (one for each leg) to fully open the circuit, right?. I mean, if you only open one leg of the circuit via SSR the element is still on and heating (granted at 1/4 the wattage, but still).

Click to expand...

Nope. That's not how electricity works. Electrons need to be able to get into the circuit and then back out... flowing through.. thus the term "current". If you have only one wire connected, then you have not allowed any kind of path for current to flow. It would be akin to a water pipe that had a valve on it that was closed. No current flowing.

So, the SSR is your valve. If you shut that valve, current stops and you get NO heating. The use of dual SSRs that you will see on some systems is a redundancy thing. If one SSR fails and the valve stays stuck open so that current can flow, the other SSR is still capable of starting and stopping the flow of current by itself.

Lost said:

The big complexity, and I can forego this if it is too much work and do it manually, is that I'd like to be able to use the pid to control the pump during chilling. My plan is to use the HLT as an ice bath and pump the wort through the coil until the set temp is reached. During the mash the pump will recirculate constantly so I need an easy way to switch what the pid is controlling. I have yet to buy the pump and was thinking chugger - can I run that or the march at 220? I think that would greatly simplify things.

Click to expand...

I don't think you want to do what you are considering. SSRs are strict ON or OFF devices. You cannot throttle down the pump with them, and you would instead just be rapidly turning the pump off and on, which is probably not going to be good for it.

Lost said:

Sidebar: when shopping for SSRs, I've seen that on Auber's site a 40amp "contactor" is $18 but the 40amp SSR is about the same price. I thought contactors were a bit more heavy duty, is there a reason I should prefer one to the other?

Click to expand...

Contactors are mechanical devices and are more suited for a manual override to shut the element off with certainty. The SSRs are large chunks of semiconductor material with no moving parts. These are pretty much required for applications where you will be repeatedly and frequently turning the flow of current off and on. You could use a contactor, but it would CLICK/CLACK a lot and would eventually wear out due to the arcing electricity that you would get as it mechanically disconnected the juice.

Lost said:

edited to say: I'm stupid. The element won't be hot (warm) with 1 ssr, it will just have a live wire. This seems like a non issue since I also would have the mechanical kill switch, right? I guess the other possibility is that the SSR would fail closed but since I'm always around watching this too is a non issue. Worst case scenario the temp in the HLT spirals out of control and I boil the mash, right?

Click to expand...

Right. One SSR gives you no current and no heat, but one wire is live. With a manual kill switch to cut both hot wires, then you have the ability to completely deactivate both wires.

One trick you can use if you use a contactor for your manual kill switch is to have an alarm set on the PID that will cause the contactor to shut off if the temp gets to a certain point. This can be used as a safety mechanism to catch a failed SSR before you ruin your mash. It will just disable the contactor if the temp gets too high and the heating stops.

here is what I used

http://www.ebrewsupply.com/designs/PID/50a-PID-2-2-2PID-Electric.pdf

Check out my thread to see pictures of my control panel

https://www.homebrewtalk.com/f170/my-eherms-setup-417513/