I have a new secard spa with a flow through heater that is not working. The black wire from the contactor to the heter is melted. Also the connections at the heater look to be discolored, by heat. I believe this should be covered by my warranty; however it might help if I knew how this happened.

Bad connection at the heater usually.

These things pull in excess of 18-24 amps. If the connection sucks, then the wire eventually will too.

These are easy.

Post a couple of photos. That would help.

You're right on. The wire connected at the heater is loose and completely melted through. Ichecked the nut on top and it won't easily tighten or loosen. I have a feeling it's cross-threaded.

Well they're not supposed to be easy to remove.

More than likely, replacing the wire should fix it.