Switching elements between 120V and 240V??

I have a simple RIMS setup with a 4500W 240V element in both the boil kettle and RIMS tube. BCS-460 with SSRs for each element.

The last couple times I have moved into new apartments I have been faced with a 3 wire 240V range outlet which worked ok and now a range outlet that is not accessible (drop-in range) so I'm on two separate 20A 120V kitchen circuits but always switching wires in the panel. 240V all the time would be great but not possible for us nomadic brewers who rent.

I would like to rewire my panel and add switches for each element to switch between 120V source or 240V source (I added 120V inlet to control panel along with existing 240V inlet) and while I'm in there it would be nice to have the ability to switch each element either off - BCS controlled - manual on.

I'm a little confused as to how you're using the 120V. Have you found two 120V outlets which give you two legs to get your 240V? Or are you just under-powering the elements with 120V?

Applying 120V to a 240V element will not do any harm; however, your power output will be significantly reduced (4500W down to 1125W).

When I don't have access to 240V I use a 120V outlet and under power 240V outlet. It works ok but my control panel is wired for 4 wire 240V where I have tapped into for pump power and power for BCS-460 etc so when I only have 120V I have to switch some wires around.

Main goal is being able to switch the elements between a 240V source and 120V source so I can leave the other wiring alone.

You have two legs of power, X and Y, and neutral N. Power all of your 120V components off of leg X. Feed your SSRs with leg X (I assume you have one SSR per element and are only switch one leg, correct?). The output of each SSR will feed one terminal of each element. The other leg of the element will go to the common pole of an appropriately sized DPDT switch (or relay controlled by your BCS...). One switched pole of said DPDT switch will go to N for 120V operation. The other pole of said DPDT switch will go to leg Y for 240V operation.

Thanks, when I'm not tired I'll run that thru the brain and see if I get the picture. Plumbing is easy compared to electrical.

Think I got it now but wouldn't a spdt switch work since you have only one leg of 240V on one side of switch, neutral from 120V on other and common pole going to element? Other hot is going directly to element from SSR. If I use a on/off/on SPDT then I have a built-in safety to prevent current leakage with SSR since it would disconnect second leg of circuit in the off position.

Correct. Not sure why I said DPDT. I have a SPDT relay that I am using to do this. Just make sure the switch you use is rated for enough current. I imagine it will be difficult to find a toggle switch rated for enough current unless you are using low wattage elements.