I have a Hot Springs Classic tub and want to change it from 110 to 220. What is involved in this..parts,etc.?

It must be a 1997 or newer with the IQ2000 control box. If it's older it had to be made 230V at the factory and would have a serial number that starts with FH.

The power jumpers at the terminals where the power wires come in: The jumpers to remove are between 2 & 3, AND 4 & 5. Leave the others.

The pin jumpers on the circuit board: Put the jumpers across both pins on JP-1, JP-2, JP-3. If it's only on one pin it is considered off. Depending on the year there may be a jumper on JP-5 - this has the display read in Fahrenheit.

A sub-panel is needed with a 30 amp double pole 230V GFCI breaker and a 20 amp single pole 115V GFCI breaker.

On the terminal board the wires are connected as follows:

#2 hot from 30 amp, #3 hot from 20 amp, #4 hot from 30 amp, skip #5, #6 neutral from 20 amp, and #7 is the ground. Make sure the neutral from the spa goes directly into the breaker and not the neutral bar first.

I highly recommend you hire a licensed electrician to do this job !!!