Pentair SWG IC40 temp bypass 3 wire

[Rkrans]

Hi,

I have an approximately 4-year-old Pentair IC40 SWG and I've had to replace the flow switch/temp sensor every year since owning it. Now it's reading cold (my water temp is 83F) and out of warranty; I would rather fix with a longer lasting solution. There seem to be instructions and "hacks" for the older four wire model, but my system has 3 wires with a common black wire for temp and flow sensors. I'd like to follow the instructions by @JamesW on using a Pentair 520272 external temp sensor but would love any input on how to connect the two wires to the cell. In the meantime, I've disconnected the white wire and am getting all green lights, although the ScreenLogic app indicates 0 ppm salt, the indicator on the SWG says I'm good to go- albeit without proper temp guidance.

Thank you in advance for your help!
Rick

 

[mknauss]

I think @Jimrahbe did this to his SWCG.

 

[Jimrahbe]

Rick,

On the three-wire flow switch the Thermistor is connected to the White wire and the common Black wire.

The black wire goes to both one side of the flow switch and to one side of the external thermistor.

Here is the schematic for the 4-wire flow switch as a reference.

Temp probe hack.jpg

• Jimrahbe
• Jan 9, 2021

Thanks,

Jim R.

 

[Rkrans]

Marty thank you for your quick reply and Jim thank you so much for the advice! I will order the Pentair temp probe and connect one of its two wires to the white wire going to the SWG and I will three-way splice the other temp probe wire with the common black from the flow switch and the SWG. Does that sound about right? I've modified and attached the image of the four-wire hack to show how this could be done in the three wire.

 

[mknauss]

Looks correct to me. I have done the same on my new IC40 installed earlier. I knew Jim had a fancy picture ------ we now have your fancy picture for the 3 wire. Thanks

 

[Rkrans]

And who doesn't love a fancy picture- I'm glad to contribute! Jim, I hope you don't mine my modifications to your great diagram. Thank you both again for your help!

 

[mknauss]

I modified the Wiki for the ICXX with your diagram. Thank you!