Problems with Hayward t-15 salt cell

[PoolDoc]

What made you think the temp sensor had failed? (Not challenging, just asking.)

[Jesnic]

The gold line controller was reading "hot". I turned it off and turned it on. It initially would register salt content (3300), then the generating light would start blinking and read hot, meaning not generating. I turned the controller off, set a bag of ice on the cell and let is stay for a few hours. When the ice melted, I turned the unit on and it read the temp at 174 degrees for a few seconds, then went to "hot". I tried to recalibrate. The controller went through it's calibration sequence and then read "hot" again and stopped generating. I opened the cell, cut the temp sensor wires and checked continuity on the switch. Continuity was bouncing everywhere. Figured it was shot. It should read somewhere around 8k-10k with the temp being in the mid to upper 80s. I will use my makeshift temp sensor for a while to make sure it is working, then probably order a Jandy replacement switch and install it. So far, so good. The water tests turned out exactly what the controller is reading.

[PoolDoc]

Very helpful. Thanks.

[dalpilot]

I've been having a similar problem with the temp sensor in my Turbo Cell T-Cell-15 http://www.titaniumcells.com/t-cell-15.html aftermarket cell, for a while. It worked well for year or so then started to shut down due to the AquaRite controller showing "HOT." Selecting the temp readout, showed in excess of 100 degrees F with an actual water temperature in the range of 75 to 80 or so.

I put my old original equipment cell back on temporarily just to confirm it was the cell and not the controller. Sure enough, the old cell presents the correct temperature to the controller. In addition I noticed that when I unplug the cell from the controller I get a temperature reading of 77 degrees. Pretty close to where my water temperature stays most of the season and well within the range acceptable to the controller.

This knowledge led me to a solution. If you open up the controller and remove the circuit board you will see a very thin, almost hairline thick trace, going to one of the pins of the cell connector. This connects to the temperature sensor in the cell. I took an exacto knife and sliced through that trace. Put everything back together and what do you know, problem solved. The temperature now always reads 77 degrees and cell function is back to normal!

I suspect the cell uses a thermistor as the temperature sensor and that salt water gets inside the plastic probe cover. This radically alters the resistance seen by the controller and you get these bad readings. My cell is still under warranty (3 years), but I can't afford to spare the time required to get a replacement from the manufacturer. I mean it's summer, the pool needs chlorine. Maybe this winter.

Hope this helps someone.

Greg

[PoolDoc]

Thanks, Greg.

[Jesnic]

Greg, that is the exact reason I installed a variable resistor. I can change the water temp to match what my in water thermometer is reading.