Making this thread for suggestions and to document the process of trying to fix the current issues with my spa.
New-to-me outdoor firberglass spa, 345 gallon GL700 Shoreline Spa. Specification from flyer is (2) 4 HP pumps, 46 total jets with ozonator purifier (but wiring for ozonator was severed by previous owner, so not operating) Main service panel in house has 50 AMP breaker servicing only the spa. Also have external subpanel mounted outside of house, roughly 20 feet from spa. External subpanel is 50 AMP breaker with GFCI protection. Spa was new about 5 years ago. Prior to that another spa was there. Age of external subpanel versus age of main service breakers indicates that the external subpanel was likely added when spa was replaced. Ran without issue from April of this year until mid-summer.
Spa runs normally most of the time. When spa has both pumps running, sometimes both on low speed, sometimes one or both on high speed AND is attempting to heat water, breaker at main service panel inside house trips off. Subpanel breakers have never tripped out and GFCI has also never tripped. Have reset subpanel GFCI a few times. Both sides of 50 AMP breaker inside are warm, even hot to the touch when checking breakers after spa shuts down. The top breaker of the pair inside seems to be hotter to the touch than the bottom.
1 - Could be faulty/aging 50 AMP breaker at main service panel.
2 - Could be aging/corroded heating element causing higher amperage draw.
First suggested steps, by my reasoning:
1- Because main panel breaker are hot and are the only point that has exhibited failure and are older than the rest of the components, I'm leaning toward having these two breakers replaced to see if that remedies the problem.
2- If problem persists, will replace heating assembly with new part. Could be causing the excessive amperage, but unsure why this would cause main breakers to trip before external breakers.
3- If problem persists, will look into external breaker, but seems less likely.
Any other troubleshooting advice is appreciated. I do have access to a non-calibrated multi-meter for testing. Wanting to sort this out sooner rather than later as I'd rather not have my spa shutting down during the highest demand, highest risk season: a cold MN winter.