geo1111

I've done some testing on one of the heater boards I have that failed. - Diodes D7 and D8, and cap C4 are all OK. There really isn't much on the board to test... If the relays are OK then that only leaves a few components that could be going bad. - The IC at U1 is the Microchip controller for the board and likely has some programming in it so it can't be replaced I'm guessing. - The linear 1 axis hall IC at U3 is used for current measurement and the docs do say it is subject to electrostatic discharge issues whereby it loses its programming. It's a Sentron CSA-1VG-SO. - The IC at A1 is what I think may be the most likely problem. It's a Vishay CNY17-3 optocoupler https://www.vishay.com/docs/83606/cny17.pdf which is basically a relay replacement. It's the component that has the tape over it to protect it, and from what I'm told there have been known issues with it going bad - hence the tape. It's also the component that is easiest to replace on the board and see if that fixes it. Thoughts? George

I just had another failure of this board on the hot tub - it lasted 1 month. When I asked the tech on the phone he said when the red LED blinks it means the relay on the board has failed and has to be replaced. Is there anything else about the tub that could be causing the board to fail like this? The tech didn't have any ideas, and neither did the manufacturer. Thanks

I replaced the board today and the tub is heating fine again. There is what appears to be an area of subtle surface melting on one of the relays. I wonder if it didn't fail? There are no other obvious signs of damage on the old board.

Will do. Thanks again.

Thanks for your response. It's set to 18V / "Old"

I have a 2001 Hot Springs Grandee and replaced the heater relay board in it with the updated 77119 board in August when the tub stopped heating. The tub then heated fine until October when the board failed again (the red LED on the heater board was blinking rapidly and GFCI resets did not reset it). I replaced the board again in October and it worked fine until now (December) when it has failed again (heater board red LED blinking rapidly). That's an average of 2 months per board. The circulation is good, filters are clean, water is good, etc... Is there an issue with these boards or is this an indication of another problem? Thanks for any suggestions!