Bad Flow Switch?

Kit

Well-known member
Mar 10, 2016
232
Medford, Oregon
I have a Pentair IC20 SWCG. During the past month, the readout on my EasyTouch control panel indicated "0 ppm" of salt. However, my test kit showed a salt level of 3,400 ppm. By rebooting the system, the SWCG apparently starting "talking" with the EasyTouch & indicated the proper salt level. Given my limited knowledge, this seemed to point toward a faulty thermistor/flow switch.

Yesterday I shut down the system to replace a pvc fitting to my heater. After I powered on the system, the SWCG displayed a red flow light & the salt level lights blinked back & forth between red & green.

Since all system valves are open & the filters have been recently cleaned, it doesn't appear that there is a water flow issue. (However, I will remove the SWCG cell & inspect it for any blockage). Again, this seems to point toward a faulty thermistor/flow switch. As a side note, I did notice that, in spite of an indication of "0 ppm" on the EasyTouch control panel, the status displayed "OK; No Errors".

Three questions: (1) Is the most likely problem a faulty thermistor/flow switch? (2) If indeed that is the problem, can I assume that the SWCG is still generating chlorine? (3) Is the flow switch (SWCG mfg. on 11/24/2015) a 3- or 4-wire type?

Thank you so much for sharing your expertise!
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,620
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
0 Salt reading indicates bad serial communication (RS485) between the IC and ET panel. It happens from time to time and can be random. The thermistor on the flow switch can go bad but that does not typically cause a 0 salt reading. It usually shows up as a big difference between the true salt level and what the IC reports when the temperature is not 77F (the IC can sense a bad thermistor and if it does go bad it simply defaults to 77F as the water temp). This Wiki page has a diagnostic you can perform to see if the thermistor is bad -

 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
23,157
Bedford, TX
Kit,

The railroad crossing like "flashing" lights is normal during a power up sequence..

The solid red flow light could be a bad flow switch, but more likely actual low flow due to a dirty filter.. If you can stick your hand in front of a pool return and can feel a good strong flow of water returning to the pool then that would indicate a bad flow switch.

As long as the salt light on the cell is green, then the zero reading on the EasyTouch is just an indicator issue and does not effect the way the cell is working.. "Sometimes" replacing the flow switch assembly can make the problem go away, but it does not actually fix anything.

You want to buy the new 3 wire flow switch to replace what you have now.. Does not matter if what you currently have is the 3 wired or 4 wire flow switch.

If the flow light is on red, the cell will not make chlorine. If the red low salt light is on the cell will not make chlorine. When the cell is making chlorine the "Cell" light will be solid green. Keep in mind the cell light is only on when the cell is actually making chlorine.. If the output % is set to 50%, then the cell light will be on for about 2.5 minutes and then off for about 2.5 minutes.

Thanks,

Jim R.
 

Kit

Well-known member
Mar 10, 2016
232
Medford, Oregon
0 Salt reading indicates bad serial communication (RS485) between the IC and ET panel. It happens from time to time and can be random. The thermistor on the flow switch can go bad but that does not typically cause a 0 salt reading. It usually shows up as a big difference between the true salt level and what the IC reports when the temperature is not 77F (the IC can sense a bad thermistor and if it does go bad it simply defaults to 77F as the water temp). This Wiki page has a diagnostic you can perform to see if the thermistor is bad -

JoyfulNoise: Thank you for the link. I will spend some time to absorb the info.
 

Kit

Well-known member
Mar 10, 2016
232
Medford, Oregon
Kit,

The railroad crossing like "flashing" lights is normal during a power up sequence..

The solid red flow light could be a bad flow switch, but more likely actual low flow due to a dirty filter.. If you can stick your hand in front of a pool return and can feel a good strong flow of water returning to the pool then that would indicate a bad flow switch.

As long as the salt light on the cell is green, then the zero reading on the EasyTouch is just an indicator issue and does not effect the way the cell is working.. "Sometimes" replacing the flow switch assembly can make the problem go away, but it does not actually fix anything.

You want to buy the new 3 wire flow switch to replace what you have now.. Does not matter if what you currently have is the 3 wired or 4 wire flow switch.

If the flow light is on red, the cell will not make chlorine. If the red low salt light is on the cell will not make chlorine. When the cell is making chlorine the "Cell" light will be solid green. Keep in mind the cell light is only on when the cell is actually making chlorine.. If the output % is set to 50%, then the cell light will be on for about 2.5 minutes and then off for about 2.5 minutes.

Thanks,

Jim R.
Jim: Thank you for the response. The "railroad crossing flashing red & green light" continued long after the power-up sequence. As I mentioned, the filters were cleaned recently. So I am confident that dirty filters are not the issue. I also removed & inspected the SWCG. It looked clean with no scaling whatsoever. That being said, it seems to me that the flow switch assembly is the culprit. Am I thinking correctly? Thank you!
 
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