2008 Hot Spring Sovereign 220V trips 20A GFCI breaker

[zroger73]

A few weeks ago, the 20A breaker unexpectedly tripped after the jets had been running about an hour or so. After resetting the breaker, it would trip again a few seconds after the jets were turned on. I didn't run it much after that except for a few 10-minute cleaning cycles. Last weekend, it ran for 50 minutes then tripped again without warning. This time, I reset the breaker and all was well until I started the jets at which point the breaker would immediately trip. I temporarily moved the jet pump circuit to the 30A "heater" breaker. It tripped. I then temporarily moved the jet pump circuit to a 15A non-GFCI breaker. It did NOT trip. At no time do I measure the jet pump drawing over 9.9 amps, so I'm not tripping out on over-current. It must be tripping out on ground fault. The reason I tried other breakers was in case the 20A GFCI breaker was "weak". All "hot" wires to ground measure at least 1 megohm. I re-seated all the wires in the input terminal, re-seated all "slip on" terminals, and loosened and re-tightened all readily-visible grounding screws. I will say that ONE of the line terminals in the control box read 220K ohms when I had my positive lead on ground and negative lead on the terminal, but this calculates to 1 mA of current - well below the 5 mA of current required to trip the GFCI breaker on a ground fault. Since re-seating everything, I haven't been able to reproduce the problem. Should it reoccur, is there a better/suggested way to diagnose ground faults? I've been around electricity and electronics all my life. I work with 3-phase, 480V equipment at work up to several hundred amps. I program industrial PLCs. I know how to safely work around high voltage and I fully understand the importance of grounding and the need for ground fault protection devices, but I'm open to more efficient troubleshooting ideas.

[Chas]

Verify that the shaft seal on your jet pump is not leaking. Even if it is not currently leaking, check for a line of calcium showing a history of where it may have leaked in the past. A tiny bit of water at that end of the motor gets drawn right into the cooling fan, and can give you a ground fault, which may dry up and go away by itself.

Water in the conduit is also something worth checking out. Good 'ol shop vac can help here.

If a GFCI breaker gets weak, it is usually the Ground-fault part which goes first.

HTH

 

[zroger73]

I appreciate the tips. Since loosening and tightening everything (whether coincidence or not), the spa seems to be working normally. One of the first things I did was to inspect for evidence of leaks around the pump and motor shaft, but did not find any - everything inside the compartment was dry and clean. I'll add that the pump and motor were replaced about a year ago due to an intermittent metallic knocking sound followed quickly by a breaker trip. The noise had started just before the 5-year warranty was up, but the tech was unable to reproduce the problem during the warranty period. Naturally, once the warranty was up the problem came back. Watkins agreed to replace the pump and motor at no charge and it worked fine for about a year until recently when this seemingly different problem occurred. I cannot confirm whether the original problem was causing the breaker to trip on ground fault or overcurrent, but it sounded like there was a piece of metal inside the motor that would occasionally get thrown around and wedge itself between the rotor and stator - a slightly more muted version of the sound you'd expect a food disposer to make if you dropped a rock down in it while it was running.