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Call them up and ask for the board back, since the board is yours. Then either get an electrician or another service company to reinstall the board on your tub. If the same error problems pop up then I would pay. Or you could call Pacific and ask them to test the board for you and send it to BC. Your problem didnt sound like a board issue.I dont want to start issues but your tubs only a few months outta warranty and your board "goes" I would have at least tried for warranty. Since you paid a good chunk of change for your tub. I guess the warranty switched to 5 years when they went to the XM pack.
I work in a similar field and I have to tell you that the level of technical expertise is very weak, and spotty at best. There simply aren't enough qualified techs out there so the average customer is left with parts changers and trial and error guys. .
The board if defective is different than a sensor if defective. The board, if it is the problem, will not show any icons, lights or heater information on your topside controls. The sensor if out of balance can be checked via a dip switch on the circuit board. The board is easy to replace and expensive, most techs like to do this type of work.......which causes the board to be the default solution to most weird problems. I think you have a high limit sensor that is a problem, or something temostatically related. I know nothing about the model of tub you own. I will support that hot tub repair can be a process of elimination, however the process should begin at the least expensive part and work up. Starting from the board and working back is a little sketchy. Good luck and email me if you have further questions