Pentair Intellichlor Temperature Sensor Hack

MyAZPool

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Jul 3, 2018
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Arizona
Moved from here... https://www.troublefreepool.com/posts/1668423/bookmark

dk,
If you just cut the wires going to the thermister (not the flow switch) the cell will think the temperature is a constant 72 degrees.
The problem I see is that if the thermister is not working, it may make your salt reading so far off that the cell will always show low salt, even when the actual salt level is very high.
I modified my system per instructions by JamesW.. I basically bought a standard 10 K thermister and mounted it in the plumbing, just like my EasyTouch temp prob. I then disconnected the flow switch thermister from the cell and connected the external thermister.. That was about a year ago and so far it has been working great. The down side is when you take the cell out and want to take it away from the equipment pad, you need to also take the external temp probe out of the plumbing...
Thanks,
Jim R.
Hi Jim
I've got a question for you along these lines, for my own purpose in the event that I ever experience the same IntelliChlor issue.
What would be the result if I were to pigtail the connection from the automation water temp thermistor instead of plumbing in a new thermistor? In other words, from the automation water temp thermistor, one set of wires connect to the automation IC board and another set of wires to the IntelliChlor thermistor connection similar to what you did. Just using the same thermistor for both purposes. "Do you think this might cause issues? JamesW, thoughts as well?

I was also thinking that I could wire-in some sort of wire "quick-disconnect" at the IntelliChlor in case I would need to remove the IntelliChlor from the plumbing for some reason.
Thoughts?
Thanks in advance!!
r.
 
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Jimrahbe

Mod Squad
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Jul 7, 2014
13,544
Bedford, TX
R,

I don't think you can use the same thermister for two different inputs... You really don't know what the circuity looks like in the two circuits.. Connecting the two circuits together could have unintended consequences... For the cost, it does not make sense to me..

I thought about quick disconnects, and it is just as fast to pull the thermister out. But it sure can't hurt anything..

Jim R.
 

ajw22

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Jul 21, 2013
7,806
Northern NJ
Thermistor works on varying resistance based on temperature. The device it is connected to measures the resistance. Connecting the thermistor to two devices will not give the correct readings to either of them.
 

MyAZPool

Gold Supporter
Jul 3, 2018
955
Arizona
R,

I don't think you can use the same thermister for two different inputs... You really don't know what the circuity looks like in the two circuits.. Connecting the two circuits together could have unintended consequences... For the cost, it does not make sense to me..

I thought about quick disconnects, and it is just as fast to pull the thermister out. But it sure can't hurt anything..

Jim R.
You can't use the same thermistor for two different devices.
Thermistor works on varying resistance based on temperature. The device it is connected to measures the resistance. Connecting the thermistor to two devices will not give the correct readings to either of them.
Thanks all...
All the explanations make perfect sense now.
Yea, it was just one of those :unsure: moments. So much for my 'bright" idea. :p
Thanks again!!!
r.
 
Last edited:

JoyfulNoise

TFP Expert
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May 23, 2015
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Tucson, AZ
If you find a good quick connect solution that is compatible with being outdoor in hot sun all day, please post. It needs to be low resistance though so as to not add to the 10k resistance.
 

mknauss

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May 3, 2014
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Laughlin, NV
If you add a thermistor to replace the one in the flow switch, would it not be better to just run its wiring into the Easytouch panel and put it in place of the wires from the IC flow switch?
 

JamesW

TFP Expert
Mar 2, 2011
15,509
If you add a thermistor to replace the one in the flow switch, would it not be better to just run its wiring into the Easytouch panel and put it in place of the wires from the IC flow switch?
That won't work. The cell measures the resistance and communicates the salinity to Easytouch.
 

JamesW

TFP Expert
Mar 2, 2011
15,509
There's a thermistor in the flow switch.

There are 4 wires going from the flow switch/thermistor to the cell.

Red and black go from the flow switch into the cell. Green and white go from the thermistor into the cell.

So, you're just cutting the green and white wires going from the thermistor to the cell and connecting the external thermistor instead of using the thermistor in the flow switch.
 

mknauss

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May 3, 2014
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Right. The green and white wires go to the Easytouch panel from the flow switch. Would you not just run the wire from the thermistor you add to the Easytouch panel, and remove the green and white wires that come from the flow switch to the Easytouch panel?

Sorry -- just trying to get my head around this. I may do it.
 

Jimrahbe

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Marty,

All 4 wires from the flow switch/thermister go into the cell.. None of those wires goes back to the EasyTouch.

Jim R.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,654
Tucson, AZ
Marty,

Pull the dust cap off your cell and it looks like this -

111171

You’re cutting into that smaller grey wire, not the big black one.
 

mknauss

Mod Squad
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May 3, 2014
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Laughlin, NV
As Matt posted that pic I walked out and looked -- OK -- you would take the two wires from the external thermistor and tie them to the green and white wires going into the cell. Got it.

Thank you.
 

JamesW

TFP Expert
Mar 2, 2011
15,509
Also, note that the wires going from the power center to the Easytouch communication port should be yellow and green, not white and green. It's a completely separate thing.
 
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