Leaky salt cell

[jerryk1234]

My Hayward T-15 cell has developed a serious water leak. Bought a new one on Amazon, that's installed & working ( & not leaking ), now. But I really would like to fix the leaky one. It's only about a year old, and there's plenty of life left in the electrodes.

Popping off the end cap, the problem is obvious; the seal where the wires come out has failed. Cracked in the middle. So I need to
redo it somehow.

It's a hard rubbery substance. I can probably drill & grind it out. But what to seal it with now? Right now, I'm considering polyurethane caulk. Another - superior - alternative would be a two-part polysulfide sealer, such as 3M "Pro-seal". If polyurethane
is good enough, I'd rather use that. Pro-Seal is a real PITA to deal with. But it would absolutely work. Pro-seal is used to seal aircraft fuel tanks. Overkill....

Another alternative would be to fill the whole cavity with epoxy.

 

[mknauss]

If only a year old, file a warranty claim.

 

[jerryk1234]

OK,
I got almost all of the black crud out. It looks like some sort of modified bitumen. It's hard on the outside, but as you penetrate it, the insides are soft. The actual leak was as follows:

There are three binding posts inside that cavity, going to the actual salt electrodes. These are not sealed where they penetrate into the water area. There is only a serrated washer under each nut. One of the holes was slightly larger in diameter than the bolt going through it. That hole shows the stain of water passage.

So they didn't bother sealing those binding posts, choosing to instead depend on filling the entire cavity as a seal. The trouble with that is --- PSI. The total pressure on anything is the PSI multiplied by the area of the thing.
The area at the binding post is very very small, but the area of the entire cavity is large. By letting water go through the small area around that post, the entire PSI of the system was applied to the large area of the sealing
cavity.
My solution: I will install an O-ring on each binding post, under the fixing nut. Then restore the connections - which got a bit munged when I removed all the sealant. Then fill the whole cavity with high strength epoxy.

 

[mknauss]

Ignore the warranty now, you have modified the cell.

 

[jerryk1234]

Should be all fixed. I cleaned out the cavity, filled each hole around the binding post with Hylomar HPF sealant, put on an O-ring, tightened down. Restored the wiring with new ring connectors, soldered. Then filled the entire cavity with high-strength epoxy. Since I have a brand new one now in service, this becomes the spare.

WRT guarantee: I really should have returned this when I first got it. It leaked from the get-go. But I managed to tape it into submission with self-fusing silicone tape, and I just got lazy.