I pulled the cover off of my box to check the limit switch, I taped all of the wires into bundles to insure they went back together into the wire nuts in the right combinations. The two white wires either slipped out or I didn't mark them....

One of the white wires is from the power supply cord and the other goes into the bundle going down to the air switch.

I don't have an extra wire nut left over which means
a. I dropped it somewhere and can't locate it.........
b. or the white wires go into another of the bundles
c. or the white wires just need to be connected with a new wire nut

Thanks for any help that you can give me!

The spa was running before I pulled the cover to check the switch

Okay, I took a chance and twisted the two wires together with a wire nut and the tub is running again. Now to figure out why it's not heating up.......

heating could be one of several things, as I just went through this, let me try to help as much as possible.

first thing I would check is your flow. If you don't have flow, it can't heat.

flow could be one of two things, air-locked (air in the lines that won't allow proper flow of water) or you could have a blockage in the lines. If your filter is dirty, this could also prevent the water from flowing as needed.

You check for air-lock by bleeding your circulation pump, if you have one. Mine gave me troubles but I stuck with it and eventually I got it bled.

Next thing I would check would be your heater element but 3/4 of the time, the problem is an air-lock. If the air-lock doesn't work then I'd refer to postings here for element problems.

It would help a lot to know the symptoms - is it kicking GFCI?, is the element heating up but not the tub? have you tried priming your pump without the filter (not recommended but will allow you to determine whether the filter is dirty or not)?

I'm not one of the pros on here but as I've just had the same issues, I thought I'd try to help. I paid a guy an outrageous amount to come and help me fix my tub and he didn't have a clue so I advise all to attempt on their own before you ever call a guy out. Lost over 400 on that deal.

Good luck.

You didn't mention if you pressed that little red button in or not. If that is out, that would cause a no heat condition. Do you hear a click in the control cabinet when you turn the t-stat up? If so, the red button is probably in, but just press it to be sure and see what happens.