You can replace one 4 wire sensor with two 2 wire sensors - one sensor for the differential function and one sensor for the digital display module.  An additional hole will need to be drilled. The extra hole should be of the same diameter and in the same general location as the hole for the original 4 wire sensor.  
 Surplus item to be discontinued.
 
   Heliotrope Pool Water Sensor with 4 
 conductors and Hose Clamp   This extra durable 
 and virtually indestructible stainless steel sensor 
 truly guarantees years of corrosion resistant performance. The sensor 
 is wired into the system and signals the controller unit with readings on the 
 pool water temperature.
  Product Benefits: • Maximizes pool 
 temperature
  Product 
 Applications: • Use with digital 
 temperature display  • Used to measure 
 temperature of the pool's water  • Used in conjunction with the Heliotrope HelioMatic 
 Solar Pool  • Control Unit - Model: 
 HM Series  • Used as a 
replacement for  the Heliotrope HelioMatic Solar Pool  • 
Control  Package #1 - Model: HM-PKG • Can  be used with any Solar 
Control unit that requires 10K  sensors
  Product 
Features: • 4 
conductors (wires)   • 2 thermistors potted in  one plastic sensor well, 
    with each of the two wires  shrink-wrapped together. 
 • Stainless 
 steel construction for extreme durability • One year factory 
warranty
  The 
ISD-1.0-10K should be installed  in the suction line from the pool between 
the pump and the filter. The dual  thermistor format in the ISD-1.0-10K sensor 
satisfies two functions: 
  1 -  Water temperature for the solar 
differential and  2 - Water temperature for  the Display in 
the Controller 
Two wires from one thermistor 
 going to the Pool Sensor position on the low voltage terminal strip and two 
 wires going to the Display position on the low voltage terminal strip. This can 
 be verified through ohm resistance.  
Note: Theoretically, the 2-wire IS-1.0-10k 
sensors can be used in conjunction with the display unit by incorporating two 
 IS-1.0-10k sensors side-by-side. The  IS-1.0-10k sensor for the display can be placed anywhere in 
the system (return  from solar, ambient air, spa) to get a temperature reading 
at the controller  display module.
  Product Manufacturer: JED Engineering 
  
   The sensor is attached to the  PVC pipe; this 
 requires drilling  a hole in the PVC pipe, and using  the stainless steel 
 hose clamp [included] to secure the sensor in 
 place.
 
 
  
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