Pentair IC40 Blowing Fuses

jfwireless

Member
May 23, 2025
9
Naples, FL
My Pentair IC40 salt cell went dark and quit working. Checked fuse in PC100 power supply and it was blown. Replaced fuse, started pump and blew fuse again. So I pulled the IC40 power cable from the PC100 power supply and replaced fuse. Turned pump on and fuse did not blow and green LED is now on on circuit board in PC100 power supply. So most likely IC40 is bad or needs to be cleaned, but it is over 4 years old now. As the IC40 is now over 4 years old I) bought a, new salt cell. Prior to installing new cell I want to check out the PC100 power supply and insure it is good and will not damage the new salt cell. Now I know the PC100 provides around 30 volts DC to the salt cell and two of the wires are for this power requirement , but there are four wires in the power cable, so what do the extra two wires do, and does anybody have a pin out of power and what the other two wires do in the power connector on the bottom of the PC100 ? Ant trouble procedure for checking the PC100 Power Supply ?
 
Welcome to TFP.


The flow switch also contains a thermistor that senses water temperature. The water temperature is used for the salinity calculation. If the thermistor is failing the salinity will be incorrect.

Flow switch has 4 wires on cells manufactured before September 2018:
  • Red/black - flow switch
  • Green/white - temperature sensor
Flow switch has 3 wires on cells manufactured after September 2018:
  • Red - flow switch
  • White - temperature sensor
  • Black - common
 
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Pentair_IntelliChlor_Power_Center_Surge_Board.jpg
 
So I checked the black and red leads from the PC100 to the salt cell for power, I have 30 VAC not 40 VDC, so I assume the internal circuit board called a surge board also rectifies the AC from the transformer into DC correct? If yes than I need to replace the rectifier on the surge board or just buy a new surge board ?

Jim
 
Cells have worked with voltage down to 26V. I would try with that surge board and see if the cell works. The low voltage will not damage anything.
 
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Jim,

'My" system had 35 VDC when the cell was making chlorine and about 40 VDC when the cell was not making chlorine.. That does not mean that all systems are exactly the same.

I agree with Allen.. low voltage will not hurt your new cell.. Fire it up and see if it works..

Thanks,

Jim R.
 

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I checked red and black wires from PC100 to IC40 salt cell for DC first, I got nothing. I than checked for AC and got 30 VAC 60 Hertz. This is not fantom power as the 10 amp fuse in the PC100 blows when connected to the IC40. I am assuming the rectifiers in the surge board are shorted putting raw AC from the transformer directly into the power feed to the IC40.

Jim
 
AC voltage reads lower than DC because AC is measured RMS, not peak, but DC is rectified and then smoothed with capacitors and will be close to peak, which is about sqrt2 x RMS, so 30 x 1.41 = 42.
 

Surge Board Repair.​

There are two functions for the surge board:

  1. Protect the communication lines between the controller and chlorinator from electrical surges. This is done using clamping diodes and is normally non-destructive, but sometimes the diodes are overloaded and fail. (Some pictures in this forum of this kind of failure).
  2. Rectify the 24VAC from the transformer through a full-wave bridge rectifier to get ~32VDC for the IC40.
The IntelliChlor Power Center and the Pentair IntelliCenter, EasyTouch, IntelliTouch with integrated Intellichlor power have different surge board designs. The automation surge boards are more prone to requiring replacement then the Power Center surge board.

The IntelliChlor Power Center Surge Board P/N 521034Z looks more robust with a large heat sink...

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