Heater Tripping

[mattwaugh7]

I've been googling all day and narrowing down the issue. I have a Megatrol Spa Controller in my LifeSpa DS-660. It was working fine and all of the sudden stopped. When I first bought the hot tub, I had trouble getting it to work and it turned out to be a bad breaker. I tried that first, not a bad breaker.

1. The GFCI breaker at the sub panel has been tested and working right (Including the neutral). I swapped it out with a non-GFCI temporarily because every time the hot tub trips, it trips both breakers and its even harder for me to test.

2. The GFCI breaker in the hot tub will trip until I either turn off the heater from the dial, or unplug the heating element. The pumps will run fine on high and low if the heater is disconnected.

3. I have used 2 OHM testers to test the heating element and it is getting between 12-15 OHMS. I've been getting mixed answers about this. Most sites are saying that this is a good range and would mean that the element is fine, however some sites are also saying that if it only trips when the heating element is unplugged, that means it's bad.

4. When I test the voltage coming from the wires that are going to the heating element while unhooked from the element and not tripped, they aren't showing any voltage. I do get voltage if I test the wires before the relay just before the element.

My conclusions are one of 3 but I'm hoping someone could shed some light on this. Either the heating element is bad (looks perfectly clean inside and has good OHMs), the relay is doing something wrong, or there is an issue with the pressure sensor.

Any help would be greatly appreciated!

[Tman122]

Jump the pressure sensor to eliminate that. How are you testing the ohm reading on the heater?

[mattwaugh7]

Thanks for the reply!

I have two different multimeters. One just has a single OHM setting so when I pulled out the element, I touched both ends and it gave me the reading. The other I put to OHM 200 and it gave me the same reading. I just don't know if it's possible for the element to be bad if the OHMs are fine? Or maybe that's not fine haha.

[bud16415]

A GFCI is a very sensitive device and compares the current on the hot leg to the return current after the device and any slight difference is saying some tiny amount of current has found a path to ground at the device. As an example the current on the hot leg is 20A and the current in the neutral is 19.995A that 5mA going to ground could be potential in the water or shorting thru someone touching the tub and grounded. The GFCI then opens the circuit instantly.

When you check your resistance in the heater you will read correct as the heater has not burned up. There is some tiny break in the insulation system that is making another parallel path to ground. The likely spot would be at the terminal passing thru. You wont see signs of arc because the GFCI is shutting it down so fast. If it wasn’t in there the current path would heat and then pass more current and then blow thru and trip the current breaker feature of the GFCI.

By that time it would be too late for people in the tub maybe.

I would say with it out and the tub works fine and you put it in and it trips there is likely some leakage of as little as 5mA. 

[Tman122]

Yes,as stated just because your getting a good ohm reading when the heater is out does not mean it is good. It means the element your testing is good. But the heater still may have a GF.