Wrong solar reading

[Ryano2121]

My SolarTouch says it's 20*F on my roof even though the air is 86*. I cut and stripped the wires going into the SolarTouch from the water and solar sensors just to make sure that wasn't the problem and it isn't.

I'm assuming the next step is to replace the solar sensor? When Pentair was out to fix my pump they said the water temp sensor was not a Pentair brand and that that could cause a misreading. So it seems like it would be good to replace the solar season with a Pentair brand one anyways.

Just want to be sure before I climb up there since I'm terrified of heights!

 

[Isaac-1]

This does sound like a typical failed sensor

 

[chiefwej]

There a chart somewhere that gives you the conversion from resistance to temperature. I used it to test and confirm proper operation of my sensor.

 

[Ryano2121]

I replaced the sensor and it still isn't working. Luckily it's under warranty.

 

[Isaac-1]

Have you checked the resistance to the wire going to the sensor?

 

[bobby1017]

I had something similar, replaced the sensor, didn't help, finally found that the wire from the controller had been chewed by something.

 

[chiefwej]

An ohm meter and the chart (which I think I saw in the manual for my solar control unit) will tell you is the senso is working properly.

 

[Isaac-1]

chiefwej: The OP has a Pentair Suntouch controller which I think uses a different calibration curve from the ones used by the Hayward Aquasolar controllers which have the chart printed on the cover of the manual.

 

[chiefwej]

Every sensor I've seen uses the same standard calibration. I changed my controller to a Pentair SolarTouch and didn't have to change my sensors. I think they are all 10 k sensors. Here is a listing for the standard sensor that most every solar system uses.

Amazon.com : Goldline, Jandy, Pentair 10K Water/Air Temp Sensor-New : Swimming Pool Solar Heaters : Patio, Lawn Garden

 

[Isaac-1]

They are mostly 10K sensors, but they have different curves so all read the same at the 10K point (77 degees F), but vary at different rates the farther you get from 77 degrees F, which means you have some ability to interchange on units that only cover swim temperatures as they still stay fairly close near 77 degrees F, the problem is ones with digital readouts, freeze protections, etc.

I think the Hayward solar products use "Z" curve thermisters, not sure which curve Pentair uses, maybe S curve, which differs from Z curve by about 7 or 8 degrees for the reading at 32 degrees F on one to the other.

p.s. regarding your link, buy one and read the ohms for yourself in a glass of icewater vs a genuine Hayward, I have done it with ones sold as universal on ebay