Control board says Balboa the part number is 51084.
Installed new in 1999. I believe that the breaker in the house box is ground fault protected. It does not say GFCI on it, but there is a yellow button that says push to test and the bar between the two switches says common trip.
No cut off near the tub. We remodeled part of the house two years ago, the inspector told us that we didn't need one since it was installed before it was required. Should we have one put in?
Last year we were getting an SN1 error with breaker trip. Replaced the heater element and it worked for a few weeks. Got the SN1 error again with breaker trip and replaced the temp. sensors. Worked for months.
Spa will now stay on for longer than 10/15 minutes only with Pump 1 disconnected (it trips the breaker). Pump 1 does the circulating job. Pump 2 is identical to Pump 1 so I unhooked and changed locations of the pumps. Same issue.

Thought that I would follow up with the solution finally.
When the Coleman was originally wired the guy that we hired took the 240 from the dryer connection that was not being used. They were aluminum wires (that were apparently too thin). He cut them and tacked copper wires on that ran outside to the spa. Nothing was put on the connection between the two different metals.

The solution was to have the spa wired copper right from the house electrical box. We also added the breaker at the spa. Has been working for two years.