Our 2 year old hot tub has been out of commission for a week. The gcfi on our dedicated hot tub line is switching off each time it starts a heat cycle. It will run for 5 minutes then stop. After that, the switch will not reset. Wondering what it sounds like to someone who knows: a gcfi problem or a hot tub problem?

Sounds like you may need to replace your gfci, try a 20 amp, it may be over heating.

Sorry or is 220v in wich case you heater elements may be starting to go. Good luck.

Most hot tubs use a 50 amp GFCI. If you have a meter you can check to see how much your tub is drawing. To see the peeks hit circulate, lights and heat all at the same time. Two years is a bit early for a tub or heater to be going out but nothings is impossible. I'd start by suspecting the GFCI, check the specs first before you buy a 20 amp.