Wiring advice please

We're wanting to add an element to our HLT for an eherms system. The idea is to build a very simple controller with just one pid and ssr to run a single element. With this design we could easily add an element to the BK at a later date, and just unplug the HLT element and plug in the BK element to use the same controller... now, I'm not sure if most guys start simple and work their way up or if everyone jumps straight into the more complex controllers but I can't seem to find a simple wiring diagram for what I need.

Not one I totally trust anyway.

This is the closest I've found, I think, but in this diagram, if the switch were off the PID would lose power. How can this be modified so that the switch will prevent the element from firing but allow the PID to remain powered?

Is there anything else wrong with the diagram?

Thanks in advance for all your help.

Diagram is for a 120V system. With the pump being controlled by this system, you would be limited to a 1650W element on a 20 amp circuit. That's pretty low for a HERMS system. A 240V system would allow much higher power. So, do you want to stay with 120V?

If you do want to stick with 120V, you could take the power for the PID from in front of the current switch. The PID would then be powered up whenever the control box was connected to power. Of course a separate switch could be added for the PID power. You should also add a switch for pump power.

Brew on

Just look at Kals diagrams and only use one pid, one ssr, and one contactor. Your 120 circuit fires the coil on the,contactor and that supply's power to the ssr/element. You can leave out all the alarms and indicator lights if you want...but at least the element on light is helpful.

I am definitely considering Kals diagram, just trying to be sure I've got my ducks in a row before I start building. I'm very much still in a research phase, and I love keeping a thread running while I learn a new topic.

I still have a lot of learning to do though, because I definitely want 240.