Balboa 2000 M7 - shocking power and feedback to ground - Heater? Relay?

[Garydee]

On our "new to us" used spa with a Balboa 2000 M7, running 220V. The unit appears to work fine except for;

• Heater - the heater relay would close but not connect. I cleaned the contacts and now works fine.
• Touching the water with a finger (standing barefoot on concrete) we noticed a low voltage shock / current.
• GFI does work but has not tripped for this issue. The GFI does work properly, I found this out personally while diagnosing a bad pump motor.

Troubleshooting

• I am getting about 50+-V AC between the Neutral to the Ground measured at the Balboa control box.
• One leg of the heater feed from the control box has 120VAC (measured to the ground or to the neutral) with the heater is off.
• Unhooked the heater element and feedback dropped to 2VAC
• Heater unhooked for the rest of the measurements below.
• Between neutral and concrete floor .5 V+-
• Between ground and concrete floor 15V+-
• Between concrete floor and ether power lug (red or black) 115+-
• One leg of the heater feed from the control box has 120VAC (measured to the ground or to the neutral) with the heater is off.
• No voltage between the ground and neutral when the spa is disconnected at the quick disconnect box (measured at the GFI box).

So questions..

1. Should I be getting 120V from one of the heater feeds even when the heater is not on?
2. Could control box issues be the reason I'm getting a 50VAC reading between the neutral and ground?

Any feedback would be appreciated! Garydee

[RDspaguy]

1) Yes.

2) Not sure, but that heater is definitely bad. I would suspect it has damaged the breaker.

 

[Garydee]

Thanks for your reply. After allot of testing and searching, I found out we had an open ground upstream in the wiring. From the main box to the first subpanel was only 2 wire (2 hots and ground). On the wire out, the ground was just there, not bound to anything - a real no-no.  Down-stream from the box was the proper wire. We replaced the and updated with the proper 8/3 to the subpanel, grounded it properly and now feel safe.

RDspaguy, I believe you are correct that the heater needs to be replaced. I do get the proper ohm reading across the inputs and I do not measure any resistance from heater lugs to ground, but now with the proper wiring it does hit the GFI when the heater is attached to the circuit board.

One note, the digital volt meter threw me a loop with it's crazy voltage readings. Finally I used a 120V incandescent bulb to test between the L1 / Neutral / ground and L2 / Neutral / ground. That made the issue obvious.