RiverSherpa

I had the tub fully loaded and the circulation pump was running. I might have had an airlock that allowed the heater to get hot with no water moving through. That would account for the left post melting and moving towards the other terminal eventually arcing 240v in there. I installed the new heater, loaded the tub, turned the temp all the way down and ran a circulation cycle before upping the heat. Seem to be working good. After a couple hours at 104 the tub went into Watchdog Mode, so now I get to replace the temperature sensor. I have replaced almost every part in the front of that tub in the last month. Good times!

Continuity test on the new LoFlo heater failed. I pulled the heater and opened it up. Looks like one of the leads burned right through and fried the wiring. It looks like this lead contact points were touching, which would have created an arc. There is some melting of the right post, so the contacts may have ended up in that position after the right post heated up. Only other thing I suspect is a faulting heater that melted the right post that then moved it into a connection position with the left post creating the arc and frying the wire. At any rate, I am lucky my Hot Tub didn't go up in flames. I have a new heater on order. **** NOTE: POWER OFF AND FUZE REMOVED ****. J9 and J10 are 240 Hot to the Heater. Green Wire is properly connected to the Bar at Bottom of Pack.

I will test the Heater for Continuity. I installed a new flow switch the correct direction and it appears to be working properly. No Flow Error codes and I can see the water flow is closing the circuit. I think it's the new heater. It is a bit different than the old one as it has a reset button on the back. The button does not have any pressure to it as it just kind of slides in and out. I have tried to push it in, but it seems to get to a certain point and stop with any clicking or mechanical response. There wasn't much in the way of documentation on the external reset button, but I am guessing I should be able to push it in and get a clicking response where it holds in place and no longer slides in and out. Any thoughts on the reset button. I will grab some pics tomorrow in the day light and post them.

I have replaced a leaking LoFlo Heater on a 2014 Jacuzzi J-365 and on startup it won't get above 95. Heater light is on when temp set above 95 and turns off when set below 95. I checked voltage and have 240 across both lines. Also tested pressure switch by jumping the two pins and it behaves normally out. I also bled air on all the pumps (2 Jet Pumps and 1 Circulation Pump) to eliminate possibility of airlock. I removed filters to see if I have an issue there and still no change. I'm guessing I have a bad replacement heater or a bad temperature sensor. I have a brand new controller board, so I don't feel that it's going to be the heater relays. Any other possibilities?

Update: I got the new controller board in (Part 6600-297) and it resolved my issue. I feel that the old controller board Rev (6600-293) had a faulty chip design at U2/C2, and that has been corrected on the new Rev. The board swap was clean one-to-one on all connections and the screw holes match up. The only thing I had to do was set J8 Jumper to off in order to go from celsius to fahrenheit. I didn't have a blown Snubber Transistor, so I don't think I took a surge like you did. Maybe a smaller surge that didn't blow my Snubber or any of my fuses. Anyway, if you have any issues with you Topside Controller and you have a burn mark at U2/C2 on your board, you can bet you need a new board. Got mine through SpaCare around $300 and it got here in 2 days. Props!

I had tested out voltage throughout the board before and everything checked out. I just got the new board in (Part 6600-297), installed, and everything is working properly. It was definitely the burned area U2/C2 on the board. Another owner had the same burned area on his board, but he had a FL2 error, even though his J365 was working properly. He found he had a surge that blew his Snubber Transistor, but mine was fine. Based on these two issues with J-365 Circuit Board 6600-293, I feel that the board is faulty in my case. I installed the new REV 6600-297 that has newer a newer circuitry design on U2/C2. I had to set Jumper 8 to off in order to switch from Celsius to Fahrenheit, but other than that, it was a simple controller board swap with identical connections and matching screw holes. Props to SpaCare for getting the board out in 2 days in this world of crappy supply chains. I would have had to wait a month at least to get that board through a dealer from Jacuzzi. On a final note, Jacuzzi has very little in the way of DYI troubleshooting information and there are very few repair videos on YouTube for Jacuzzi, especially J-365. Local dealers won't touch the spa without warranty, especially if you didn't buy it from them. I Had to spend a lot of time to figure out Pump Wet End replacement, LoFlo Heater replacement, and TopSide Controller replacement. Now that I am proficient on the J365, I won't be buying a replacement tub until I cant get parts anymore.

The yellow wire splice goes to the Light DCU.

As I mentioned above the Pics, I have the power off and the Fuses pulled at the moment. They both test out ok on continuity, but will probably replace anyway since its a cheap maintenance and problem elimination step.

I also have discoloration in the same are ( U2 / C2 ). Mine looks a little worse than yours. My problem was my Topside Controller acting up, then lights out. I replaced the Topside and got lights, but no display or controls. Looking at ordering the Next Rev board 6600-297. I pulled by board and saw the same discoloration. Here I my pics:

Pulled the board and it does look like I have some burning around the U2 and C2 Area. Any thoughts on the discoloration? Im guessing this might be my issue. What would be a good source for new Jacuzzi Controller Board? Other than a distributer... they take forever. Pic Note: Power off and fuzes pulled. Backside: Controller Chip is REV 3.82 Part 6600-293C

I just replaced my Topside Controller which was acting up, then lights out on me. Got the new one installed and plugged in and got lights, but no control or display. After checking the connection and blowing it out, I finally got display and circulation, but after the first jet cycle I hear a click and I am locked out. It just displays the temp with no menu or jet control. I also had Blue Ray light and Heater Light displaying. After testing fuse continuity, voltage on all leads, and reconnecting the topside controller several times, I turned it back on and I only have lights, no control or display and no Blue Ray or Heater Light. Im thinking I have a bad harness connection on the board or the new Topside Controller is faulty. Is there anyway to test the harness connection for the topside to see if it's good? Or, what else could be causing this? Thanks for the help!

I have the exact same model and the Snub Transistor is in that same location. Definitely a standard component.