Need help troubleshooting RJ45+ (Low salt light)

Mar 26, 2014
1,230
San Jose, CA
In March of 2020, I bought two RJ45+ SWGs for my pool and a friend of mine. I installed them both and have been taking care of both pools. Mine has been a dream. I haven't had even a single issue. Went all season in '20 without having to clean the unit even once.

On the other hand, my friend's unit has had some issues. Her cell would get scale on it weekly after about the first 2 months last year. I would unscrew the cell and blow it out with water from a hose. I occasionally would see the cell maintenance light on when I got there, but that would go away as soon as I blew the cell out with water and turned the unit back on. I maintain both of our pools, but her CH is almost out of control to the tune of 800ppm. I know she's gonna need at least a partial drain by next season, but with the drought conditions here in CA, that is not an option right now.

This year I decided to try borates in both pools and it has turned out great. Her cell has yet to show any scaling at all so I thought my troubles were over. I've been noticing the temperature reading on the control unit is reading nearly 10 degrees higher than what the manual thermometer in the pool shows. That didn't really bother me that much, but now I've noticed the salt level keeps going down and down. It's so low that it trips the low salt light and the cell maintenance required light on the unit and stops making chlorine.

I installed the unit last year and added salt to 3600ppm with my Taylor K1766 test kit. I hadn't added a single bag of salt until about a month ago. That's when I first noticed the low salt light on. First thing I did was retest salt with my test kit. It had only dropped to around 3200ppm, but of course the control unit was reading down in the 2500ppm range, so I added a bag and that got it working again. I come back next week and the low salt light is on again.:mad: I added two more bags and now I'm at 4000ppm on my Taylor test. The unit was showing 3500ppm so I thought I was good.

So I show up again this week and the lights are on again! I turn the power off on the SWG and turn it back on after 30 seconds and it starts generating for a little while with salt reading in the low 3200's, but that number keeps dropping and dropping until it gets down in the 2700's and trips the lights again.

Any thoughts on what could be the issue? Is it a salt sensor? If so, is that on the control unit, on the cell, or maybe even on the flow switch? What are my options?

The equipment pad is in direct sunlight, but I built a bird cage cover for the unit to shield it from some of the sun's rays.

 
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Read RJ45+ High Water Temperature Error in…


We have been hearing about that in a few RJ45 units. Circupool seems to have a QC problem.

Move the jumper on the board to move temperature sensing from the cell to a flow switch. Since you don’t have a temperature sensor in your flow switch it will default and operate. Then to get correct salinity you need to install a flow switch with a temperature sensor.
 
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First of all love your bird cage, I would add couple 120mm case fan at the bottom to blow hot air up, you can tap into one of the bridge for the 12V power.

Second you have bought the least reliable machine by design that I have worked on, I have replaced hundreds of the PCB (most of them failed between 1-3 years), to me that is not acceptable.

Good news, there is no salt sensor, so it is calculated based on the voltage, current and water temperature. If you temp reading is wrong, there is a 5 min fix for that, see link in ajw22 post above.

Here are just one box of the bad boards I replaced (I have done at least 10 more boxes this year so far), and we only have just over one thousand customer with the RJ system.

View attachment 358101
 
Move the jumper on the board to move temperature sensing from the cell to a flow switch. Since you don’t have a flow switch it will default and operate. Then to get correct salinity you need to install a flow switch with a temperature sensor.
I do have a flow switch. From ajw22's link above, it looks like the flow switch with the thinner wire is connected to a square headed thread. My flow switch has the hexagonal threaded head like the 2nd one in the pic. However, looking at the wire, it doesn't appear very thick.

I can't really get a good look at that jumper from the pic. Is it simply 3 pins with the jumper on the first two only? Do I just move it over to the last two to change it?





 
I should have said - Since you don’t have a temperature sensor in your flow switch it will default and operate.

Yes move the jumper from the first 2 pins to the last 2 pins.
 
Thanks will give it a try on Monday. Is it easy to remove the cover to get to the mainboard?

For now, I loaded her up with 6ppm of liquid chlorine for the weekend. Her FC was still only at 5. That's a definite thumbs up to running the FC a little 'hot' daily.
 

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Update: So, I went to my friend's house to change the temp jumper setting, but when I got there, I noticed the unit working.:scratch: As I cycled through the menu, the temp reading was practically right on this time. As I got to the salinity reading, it was in the low 3200's. I did notice that the weather was very mild and overcast. I wonder if that might mean some type of overheating issue.

I spent over an hour there, and as the sun finally broke through, the temp reading started going up. It went from 78 to around 81ish in around 30 minutes and the salinity ppm began to drop as well. It got just under 2700ppm, and then I decided to just power it down and change the jumper.

Afterward, the temp reading stayed at 77 like people said, and the salinity climbed, after having it on for around 5 minutes, up to around 4000ppm. That is right where my Taylor K1766 says it is. However, it slowly started dropping and got down to around 3400ppm. I will get some feedback from my friend when she gets home from work and have her check it with me on the phone.

Still curious about RJ-45's suggestion about adding some case fans on the bottom. Could someone give me more some more detail on where I would connect them on the board?
 
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