Zodiac EI Expert SWG cell (Australia) - how to disassemble

[brendio]

So, I got lazy monitoring my pH over winter (new baby in the family had me distracted) and I got a bit of scale in my SWCG cell. It's a Zodiac Ei Expert Mid.

I removed the couplings from the pipes and unscrewed the end cap, but could only slide the cell out about an inch and half before the locating tab stops it going any further. I could not for the life of me see how it comes apart further. I persevered, and by chemical and physical means (lucky I have small wrist to fit inside the outlet to scrape with an ice-cream stick) I got it clean, but it would have been a whole lot easier if I could have disassembled the unit.

 

[Texas Splash]

Maybe I'm missing something in your scenario description, so I better ask. In the pic you obviously have the cell completely removed. Where you trying to take the actual plates out of the cell? Did you ever try to clean the cell with muriatic acid as other SWG owners do by placing it vertically on a stand and pouring the 4-1 water/acid mixture into the cell?

 

[brendio]

Thanks for the question. Yes, I removed the cell from the pipework and unscrewed the threaded ring on the end where the wires attach. I was hoping to remove the actual plates from the cell to clean the scaling off physically. As you see in the photos, the electrode assembly slides about an inch out of the housing, but won't go any further.

I had a bottle of coffee machine descaling liquid containing sulfamic acid, so I used that. But most effective was getting a paddle pop stick (I think you guys call them popsicle sticks) and sliding it in between the electrode to push the crud out. It was difficult working at right angle to the opening.

There may have been too much scale for the amount of acid I had. My user manual says if you don't have ready made cell cleaning acid to make it up with a 1 in 10 ratio of hydrochloric (muriatic) acid in water. I was nearly going to start a new thread on the pros and cons of muriatic versus sulfamic acid for descaling.

 

[Texas Splash]

Muriatic acid is generally the most popular method. Many cells have a 4-1 water/acid ratio, and only soaking them long enough to where the fizzing stops. We "try" to not use acid any more than necessary as each application of anything acidic tends to wear-off the coating on the plates themselves. Sometimes a good high pressure water nozzle through the cell works, but if the scale has adhered to the point you physically have to rub it off with a wooden stick, then muriatic acid would be the next step. I would avoid sulfuric acid and it's not good for the plates.