Need Compu pool cpsc36 info, please

[esitduk1]

New member, I'm not a pool owner, but my friend is. I am a master electrician and have inherited the task of figuring out his pool problem. The unit is a cpsc36 and is giving a "high salt" indicator light. There were no bubbles being generated by the generator unit. He called the company and was told to calibrate the unit. It shows +18 on polarity 1, and +16 on polarity 2. Calibrating the unit made no difference.

I found that the wires feeding the primary of the transformer had been pinched in two. Upon reconnecting these conductors, the generator began to make some bubbles, but not the usual amount and the indicator light remained on. I checked the voltage going out to the generator and found 4 VDC with 15 amps of current. Per the chart it should read 30 amps. The transformer lists a secondary voltage output of 8 - 36 volts.

With the voltage AND the amperage being exactly half of what I think I should see, I am left to assume that I have lost, at least, one of the rectifiers (SCR's I think). That would account for the reading. The other thought is that with the "high salt" reading, the controller is turning off part of the SCR's and is trying to reduce the amount of generation. I can check the SCR's, but it will probably require removing them from the unit to get an absolute reading and I'm reluctant to do that unless it's the only option.

Does anyone else have any experience with this set of circumstances? Does anyone know where I can get a wiring schematic?

Thanks for any help.

 

[JasonLion]

Welcome to TFP!

A rectifier failure would almost certainly result in a low salt reading, rather than a high salt reading, if the unit continued to work at all.

My guess is a short somewhere, perhaps caused by debris inside the cell. Another possibility is that it is receiving the wrong voltage, possibly setup for 115 volts but actually getting 230 volts or the other way around.

 

[RobbieH]

Since I don't see it posted, can you tell me if the salt level of the pool has been tested using an accurate method, and if so can you post the test results? In fact, a full set of results could prove to be handy.

My CPSC seems to have a mind of its own sometimes. I can have the LCD saying LOW SALT and the light on for High Salt at the same time occasionally. I've tested the salt content to be 3500, so I don't worry about it too much.

With the system operating since the repair, is it maintaining the proper chlorine level in the pool?

 

[esitduk1]

After reading a lot of posts on this site, it appears that these units are notorious for "high salt" indicators and that the company always recommends 1. calibration (which usually never helps) and 2 replacing a PCB. I have a hunch that the "high salt" indicator is a seperate problem which might have happened first and been ongoing for a little while. At the same time, the severed conductors to the transformer would have prevented any generation, I think. This is a recent event, or else the unit would not have worked at all. The unit is over 4 years old and has been working on 230 volts for the entire time so I don't think it's set up for 115 vac. I guess what I'm thinking is that the two problems are unrelated. Problem 1.....the high salt indicator is a fairly common problem with this model (evidently). Problem 2......Is the low voltage and amperage caused by the unit actually trying to limit the generator or is the reason a problem with the transformation and rectification of the control voltage.

Your idea of a short is exactly what happened. The wires were caught in the "lip" around the cover and pinched. One of them actually sparked and left a black spot on the edge of the cover. Perhaps that is what blew the SCR, or perhaps it damaged some of the other electronics. The SCR can probably be checked and most likely corrected. The rest of that stuff will probably take someone smarter than me! My other guess would be to replace that whole power pcb including the rectifiers.

 

[RobbieH]

Also, depending on which brochure or ad you look at for the CPSC units, one says the system will work up to sea water concentration (35,000 PPM), while the manual states 3000-6000 ppm with 3500 being recommended.