Intex SWG Service Light - Fixed!

mpower36

New member
May 20, 2019
1
Marshallville, Ohio
I have an Intex CS8111 SWG that's been running great for years, but this year after about 3 weeks of running fine, the service light came on and the pump shut down. Cycling the power caused the pump to turn on and the 'Working' light to illuminate, but after about 1 minute, it would shut down and the service light would come back on. Manual says that means the input voltage is low. I confirmed that I have 121 VAC at the outlet, so the house voltage isn't the problem. I can run the unit in FP mode, so I added some liquid chlorine to the pool so it wouldn't turn green while I figured this out.

I have an old CS8111 that has a bad transformer, so I have parts that I can swap. I swapped the electrolytic cell, but same issue. Just to verify the cell was good, while the pump was running in FP mode, I connected by car battery charger to the posts on the cell. The plates started producing chlorine bubbles immediately, so the cell is good. With the unit put back in order, I checked the voltage to the cell from the controller and measured 9.4 VDC. I'm not sure why 9.4 VDC won't generate chlorine, but it won't.

I opened up the control unit and hot-wired the cell directly to the 12 VDC screws on the board essentially bypassing the board. Same problem. Turns out this was a waste of time, but it eliminated the control board as a potential cause, so it couldn't be solder joints, blown fuses, or other board issues. Next I swapped the rectifier with the one from my old unit and measured the DC output to be 13.4 VDC. I put everything back in order, and it worked. Nice bubbles coming off the plates as before.
InkedSWG Control_LI.jpg

So the Intex manual is somewhat correct. The board was correctly sensing low voltage, but rather than the cause being the household voltage, it was low voltage after the transformer and the rectifier. Fortunately, I had a rectifier on-hand from my old unit, but if this is your problem, you can buy a new one on Amazon for about $5.

I saw lots of great fixes for problems with these SWGs, but none of the symptoms were quite like mine, so I hope this helps the next guy.