Circupool SI-45 blowing fuse

[brebur]

Hi folks,
I've had a Circupool SI-45 system for about 6 years, and it's always worked very well. In fact, I just replaced the cell a few weeks ago with a SI-40 replacement.

I just returned from vacation to find a pool just starting to turn green, and I find the SWG control unit isn't on. After some voltage checks, I see the internal 15A fuse is blown. I replace it, power the unit on, and the fuse immediately blows again.

So...at this point I'm not sure what to check, or what would cause this other than the control board failing in some way.

Pool: 24kgal, 4300ppm salt, 7.8 pH

The salt level is a little high, I try to keep in under 4000 but accidentally put too much salt in a few weeks ago.

Any ideas what could be going on, or what I should check? I'm comfortable testing other voltages inside the unit if that would help.

 

[cowboycasey]

If the salt is to high it is pulling to much power and blowing the fuse.. Drain water to get salt down to 3800 or so and replace the fuse and it should be good to go

 

[brebur]

Thanks for the idea.
Normally, the controller comes on and waits a minute to confirm water flow before enabling chlorine generation. But right now the fuse blows. The controller detects high salt concentration and disables chlorine generation (this worked when the salt was previously 4600 before I dropped it to 4300 and the controller turned off the "high salt" indicator).

I found this recent thread ProLogic blowing 20A fuse. that sounds similar to my issue. I'll check some of the internals first.

 

[brebur]

Fixed!
The linked-to thread discussed the rectifiers, which were my first target.

I removed both rectifiers and found one was fine while the second had a dead short on the AC to + leg. I swapped the AC input to the unused AC terminal to use the undamaged side of the rectifier, and that was it.

If this other leg goes bad, it's a $5 part to replace. Part number KBPC3510.

 

[cowboycasey]

Great job, do you happen to have any pics