Ed Z

And the winner is.....Power! Changed out the old CB for exact same, just new, and tub seems to be back to normal. Will be keeping an eye on it, but 4 hours of heating without any issues. Looking forward to a good soak tonight!

Thanks! The breaker in question is at the main box, maybe about 10 years old. Unfortunately, the previous owner only ran line for a 60A sub-box in the garage, which this is wired to. Yes, I checked the wire gauge, and its only 6AWG, so too small for anything bigger. I'm suspicious of the breaker, because when re-set, it feels "mushy". Anticipating another question, yes, there are a couple of other small draw items on the list (lights, cordless tool charger), but I've tested with everything else off, and get the same results. Ran it yesterday, with air temps in the 60's, and it ran for about 15 mins, eventually with one pump in low mode and the heater on.

Folks, Have a 2002 Maquis spa, with a 1 (of 2) new pumps and a new heater. Wired myself. Ran fine for several months, now that it's winter, seems to consistently be tripping the supply (not the GFI cut-out box) CB. Have some milder weather, so testing again, but what is reasonable to expect? In "standby mode", with only the one pump on low and the heater on is when this is happening. Is this a hot tub problem, or an electrical problem? Seems to run fine, even with all pumps on, for about 10 mins, then trips the CB. Thanks!! Z