This is an Infiniti hot tub (1997) with the vertical heater 4KW 240V, circ pump and 2 speed main pump. The spa pack is a Gecko MSPA-1

A while back the cicuit breaker would trip and I couldn't reset it.
So we checked th spa wiring and the heater wires were a little burned.
So we rewired the heater with new wires and started the hot tub.
The breaker tripped again.
Then we disconected the heater and reset the breaker and the tub ran as normal but with no heat.
So I bought a new heater unit and installed it.
The unit ran but ocasionally would trip the breaker.
Now when we reset the breaker it will run for for about 45 seconds and then trip.
Did this several times.
Then we again disconnect the heater and the unit again runs as normal.
Any ideas as to what is going on?
THANKS

Well it looks like I found the problem.

There is water getting into the bottom sealed platic base where the wires connect to the heater terminals. I noticed water dripping out where the cables enter the box.
Its probably leaking thru the seal at the base, where the terminals come thru, one of the terminals is a little rusty.

As I said, this a new unit, a manufacturing problem.
It looks like I can't get a wrench in to tighten the nut. If I can get one in, is it possible to tighten it, or will it damage the unit?

THANKS