Howzit, Rube?

Sweet!:smokin:

Not sure what you plan to do with the safety sprig either.
Perhaps a small cork? Balloon? Open vertical column?
I'd go with the open column and drop a meat thermometer into it.

The switches are easy.
Assuming they are N.O., (normally open)
Wire them in-series with the fan.
Just cut one wire to the fan, and tie those cut ends to the switch.
Glue the switch on just after the last led in line.
When the water reaches 55 Celsius, the fan will start.

From the looks of it, that will take a while.
Got a lot of copper to heat.
What does that pup weigh dry?

Bubbling with ideas, but trying to wait to see how you deal with the details.

Aloha, and Good job!

Weezard