Coleman (MAAX 351D) HOT TUB tripping HOM250GFI- 50 Amp 2-pole Homeline GFCI on low pump speed only

[TimTucker]

Coleman (MAAX 351D) HOT TUB tripping HOM250GFI- 50 Amp 2-pole Homeline GFCI on low pump speed only.
Can't get it to trip on high speed (heating or not). Low speed trips GFCI (both heating and not heating).
Unit pulls (per Fluke Clamp meter): ~9.1 amps on high speed, ~3.6 amps on low speed, ~24.7 amps heating/low, and ~30.4 amps heating high.
On low speed it can take 1-20 minutes to trip the GFCI. I have another motor/pump that I will be installing in the morning (BRG/seals rebuild). My hunch is that the slow winding is causing the problem? Is it possible the controller (SPAGUTS VS500Z) could cause such a problem?

I'm open to any advice. I did many runs today trying to get the GFCI to trip on high speed...NO GO! I was hoping the GCFI was defective or ?
Many Thanks!
Tim

 

[TimTucker]

Got the original (rebuilt) (8-8-2006) out and put back in a much newer (rebuilt-BRGS) motor/pump put back in. Filling now. Anxious, hopefully this troubleshooting process ends today

 

[TimTucker]

The GFCI tripped on low speed ~5 minutes in...GFCI, or control unit? ~100 vs $500

 

[TimTucker]

Being the owner of British car(s) since the late '70s, I feel a bit embarrassed. Why? We all know to 1st check grounds when electrical items give us trouble.

It's been over 19 hours since the GFCI has tripped. Before replacing the GFCI, I re-made the 4 ground connections at the control unit (I hade previously re-made the GFCI and motor connection). Knock on wood...

 

[TimTucker]

update, 7 days later...no further trouble...