Hello,
I just purchased an older gatsby spa (1994). It has a new 50 amp gfci on 6 guage cable. This is a convertible unit, now running on 220v. A single pump system, no air pump or ozonator. The pump is a 110v 2 speed. This spa intermittently trips the gfci, but only in the low speed setting, and when initiated by the timer. A timer check verifies that it trips at the exact start of a cycle. This never happens on high speed, i let it run for two days straight on high, no error. The heater element and jet pump are new, and have adequate power, they are both in normal amperage draw range. Could this be a possible wiring problem? Is there a general schematic? Please Help
Jim c.

For this particular problem we may go a few rounds, so you need to register and be sure that you are notified of replies to this topic the next time you post here.

First, hats off because you done this thing right by making it a full 50 amp deal with GFCI. Be sure that your connections are super tight on this thing after it's been sitting for a while. They will change! Simply installing the GFCI, Tightening down the cables in the breaker.... then pushing the 6 gauge wires into the panel while you put the cover on is enough to loosen them!

That's just a precaution that will save you 80 bucks or so in the future, not the problem that I think we're dealing with now.... well maybe ???

Alright, you say this thing is NOW working on 220. So I assume it was setup for 110 volt operation previously.

Well, you know what happens on a 110 volt spa when the pump is in low speed?

the heater turns on

If you haven't made the full conversion to 220, so that the heater will work on high or low speed, then I think you may have already identified the problem with it.... even if the heater is new.

Since you've got access to an ammeter... if you can, post what amperage readings you're seeing when this thing is running.. heat on, heat off... high speed, low speed, etc... All of these readings are important for proper diagnosis.

And unless someone's changed some wiring in this controller, then do all of your readings with the inductive loop around L1, not neutral or L2.

Thanks and let me know what ya got...

hello,
in response, here are the amp readings requested,
40.8 on high+heat, 12 on high no heat, 24 on low + heat, 3 on low no heat. Also tested jet pump, it was a cool 12 on high, rated at 13.3.
My good meter topped at 30a on the high + heat setting, had to use an old dayton meter, may not be a good accurate reading. Called a clearwater dealer who advised me to try running on low with thermostat set at 104, and also with the timer off, in hopes of bad timer circuit. It still tripped gfci after 1hr 10 minutes.
Help please,
Jim C.

Well, since it's not a RFI crazy timer, then it's back to the basics with a couple of things.

1. First, I would be sure to check the breaker temperature WHEN it trips. If it's hot, then you've found your problem.
2. If not number one, then I would disconnect both leads to the (new) heater element, insulate (tape) them and run the test again.
3. If not number two... then let me know we'll figure on where to go from there.

PS: Your meter readings are fine, (old meter or not), all we needed to do was get a general idea of what the thing was pulling from the breaker during all modes of operation.

sorry for the delay,
Took my pack down to a repair shop. The hooked it up, and claimed no problems. they advised gfci fault. I replaced gfci, and ran for two days. Once up to 100 deg., i set timer, ran for another day. Now, set temp at 104, ran overnight, and it tripped the gfci on the pack itself, not at the main breaker. Don't get it, what could be wrong?
Thanx Again!