I'm not buying into your test results. Check your meter, check your testing procedures, and then recheck your readings.

Check voltage after the double pole breaker in the house, and again at the end of the run from that breaker. Then check before the tub breaker, and again after.

Why do you have a junction box in the house for the hot tub run? This should be a straight run from the house panel to the GFI that feeds the tub. Do you have split bolts connecting the wires in that junction box? If so, you might have a bad connection there.

Sorry, didn't mean junction box. It is the panel in my house. I tested known good 115 and 230 circuits in my house; Coventional 15a outlet in my kitchen and the clothes drier 30a outlet. So I think my meter is good. When the tub is not running I test 230 across the terminals in my tub junction box and 115 when I turn it on. I also read 230 on every input and output leading up to my heater.

I have heard of 230 tubs having a 115 heater. Should my heater be running on 115 or 230?

Tim

normally 240V tubs are that way for the heater. Meaning, I have never seen a 240V use a 120V heater. The 240V heater uses less power (well less as far as power to performance ratio) and heats quicker.

What I am trying to understand is how you have 240 on your control panel, but when you turn on your heater, that same 240 drops to 120. It seriously looks like a supply issue. Perhaps if you check your voltage at your house panel, both with and without the heat running. You may have a defective house breaker.

Have you tried these checks with your element wires disconnected?

Could you possibly send me a picture of your control panel, showing all the wires to and from your heater relay? The pic you posted is a little too close to show all that I need to see. Also, if possible, can you make a notation of what terminals you have been measuring, and their readings?

Thanks

First of all, thanks for your help in this. I will try and give you all the info I can to help you. I am in a service related industry and know how important accurate info can be.

I have posted better pics of my spa internals.

I tested appr. 110 from each of the yellow terminals(heater terminals) in the upper right to ground and measured 0v across them with the heater connected and activated. This a a new heater. The old heater did the same.

I measured appr. 110v across the red and black on the left side of the conatctor at the bottom of the photo. that is what led me to go back to the GFCI.

110v across the red and black output of the GFCI. 220 across the red and black on supply side of the GFCI. Removed the GFCI and wired direct and mesured 110v across the output of the 50a breaker in my house panel.

I can try other things tonight when I get home if you need more info.

Tim

Those photos helped a lot. I added notations to one of your pictures and have explained them below:

A-D 240V Input to heater relays on circuit board
B-C 240V Output to heater from relays on circuit board
E-F 120V From onboard GFI
G-H 120V To onboard GFI
1-2 240V From house breaker

Starting from the beginning:

Turn the spa on so it is in heat mode

Check for power across 1 and 2. If you have 240, move on, if not, your feed to the spa is bad, check for a bad breaker or connection between this point and your main house panel.

Check for power across E and F. If you have 120, move on, if not, your onboard GFI is either tripped or defective.

Check for power across 3 and 4. If you have 240, move on, if not, your circuit board is not telling the contactor to turn on.

Check for power across A and D. If you have 240, move on, if not, your contactor in the lower right of your panel is bad

Check for power across B and C. If you have 240, your heater element is bad, if you don't have 240, one or both of your onboard heater relays are defective.

That's about it for now, let me know how this turns out.

All fixed now. You are not going to believe this.

Connection A was not present. The left side of the terminal block had the screw missing where the terminal block attaches to the board. Also, the terminal looked charred.

My theory: The screw slowly worked it's way loose and was arcing causing the burnt terminal. It eventually backed all the way out and fell.

The Mystery: Where did the screw go?

Thanks for your help. Without your help I never would have noticed the screw missing. As you could see, it was hidden beneath some of the wires.

Lesson: Check all electrical connections. even the ones you cannot see!

Great news..... now since you said the connection looked charred, place the wire under the far left screw, directly touching the circuit board. The reason for this is that any corrosion on that circuit can generate a LOT of heat, and this will help minimize as much of a problem as possible. Use a fine emery cloth or emery board to polish up the mating surfaces as much as possible. Be careful with the circuit board however, as that coating isn't very thick (hence the wide circuit trace you can see).

Good luck and happy hot tubbin'

(just picked up another project spa myself today...should be fun!)