Jacuzzi heater issue

[Breacher09]

I'm looking for a little help. I have a j-340 tub. It's been a great tub with no issues since I bought it new. The other day I went to use it and noticed the temp was 84 degrees.
The heater light is on, the circulation pump is running. I have voltage going out to the heater (115 volts on each leg). No error codes. The tub will not heat.

I have the mode set on standard 1 (f01)
The filters are new and clean.
Tub has not been refilled.
Tried turn power off for a while then back on.

The problem happened after a power outage ( not sure if that is related)

The local dealer didn't offer a lot of advice other than its rare to see a heater go bad.
.
Any advice would be appreciated . Thanks

[Dr. Spa™ Ret.]

The ONLY way to measure the voltage to the heater, and get a reading the will tell you anything, is to measure ACROSS the two legs. If only one leg is hot, and you're measuring from each leg to ground, both legs will measure as hot, as electricity will flow from the good leg, THROUGH the heater, and show a voltage reading on the "dead" leg.

[Dr. Spa™ Ret.]

[Breacher09]

Dr Spa, thank you so much that makes more sense to me know. After testing as you described  the problem is I do not have the proper voltage  going to the heater (I get a reading of 000.95) Might you be able to point me in the correct direction to repair this tub. I also discovered that the box were the heater plugs into has caused a black charing on the wires leading out to the heater..
Thanks for the assistance

[Breacher09]

I should have added that the relay next to the heater output  I think it said heater input did have 220 volts ( measured across both legs ) so my supply into the tub is good

[Jacuzzi Jim]

 If you do have 115v coming from each connector off the circuit board to the heater, you need a new heater.  One other thing to look for is between the two terminal blocks where the main power comes from the GFCI  is a resister thin blue circle  maybe red thing with two wires, one wire each hooked to each terminal block.    Is it fried as well, if so it was most likely a power surge of some type..

[Breacher09]

I went out this morning and went through the testing here is my results just checked voltage across the two terminals.

Heater in put  at the board below the blk box - 237 volts
Heater output  34 volts.
Unplugged heater output measured at the terminal without heater connected 37 volts.
Checked the red button ( resister?) Jim spoke about and it shows continuity flowing through it and it looks new,

[Jacuzzi Jim]

I went out this morning and went through the testing here is my results just checked voltage across the two terminals.

Heater in put  at the board below the blk box - 237 volts
Heater output  34 volts.
Unplugged heater output measured at the terminal without heater connected 37 volts.
Checked the red button ( resister?) Jim spoke about and it shows continuity flowing through it and it looks new,

  If you only have 37v coming off the circuit board to the heater, then you most likely need a new board as well.  6600-288 I can't remember the heater number.