I have attached file if you wish to take a look. I would seriously LOVE to find and solve the breaker tripping problem that has cursed me now for 2 years. But, failing that, I am looking to install additional sensors or monitors to alert me if the hot tub looses power in Wisconsin winters so I can take action BEFORE everything freezes up and pipes burst.

Honestly it sounds like you have the wrong breakers, or that you have the hot tub jumpers set incorrectly.

Depending on your model of Sundance tub (you listed year and Sentry model number but not the tub model) there may be a jumper issue.

Sundance sets up their tubs so that a varietly of different people could use them in a varietly of different ways. For expample User #1 may have all the power they could ever need and so the tub is set up to run everything all at the same time. However User #2 has an older home and their service is smaller so they can only supply a limited number of amps to the tub. As a result the Sundance service tech changes jumpers, and now the tub will only run the heater while the pumps are running at low speed.

(Assuming model) The Sentry 800 that you've listed may be able to be set up to run at three different current levels 24Amps, 40Amps, and 48Amps. These settings require (per NEC code) a 30Amp breaker, 50Amp breaker, and 60Amp breaker respectively.

Now if you notice in theory you could run the highest setting 48Amps on a 50Amp breaker, and assuming everything is running fine there would be no problems. BUT as things wear the rated current may no longer be accurate and you might actually be drawing 49.5Amps or even 50Amps. Over time the breakers will heat up and eventually one of the two may trip. This makes sense because you've stated that one or the other, or even both breakers are tripping.

A friend of mine had the same setup on a 1997 Sentry 750. He had his electrician instal a 50Amp GFCI, but the Sundance service tech failed to change the jumpers on the board. So the system was actually drawing 48Amps. His tub worked fine for 8 years before he started having problems, he changed the breaker and it didn't solve the problem. Needless to say a lot of time and money later my friend gave me the tub because he was tired of dealing with it. I started sorting things out and realized that I needed a different jumper setting. I looked for 2 months before I found someone that was willing to supply me correct information for my tub and wouldn't charge me $100 to come out and change the jumpers for me. (I would supply this to you, but I'm sure that my board is different than your's and therefore my jumper settings would be different as well.) Once I reviewed the old settings I realized that the tub was set up to use the 60Amp breaker and not the 50Amp that my friend had. I told him what I found and he wasn't thrilled with the news. I even offered to give him the tub back but he had already purchased a new one.

Good luck finding the info. You may need to contact a Sundance service tech and ask if they will supply the jumper information just so you can check the settings.