Temperature sensor for pool heater

[tmas]

My temperature sensor was installed along the pipe between my pump and my filter, in direct sunlight. So the sensor doesn't measure the water temperature and instead reports closer to the air temperature. Suggestions for a temporary or permanent fix?

10,000 gallon inground gunite pool
1.5 HP 2-speed Hayward pump
Polaris pressure-side cleaner
Houston, TX

 

[JasonLion]

Normally, a sensor mounted in that way will be quite accurate at measuring water temperature as long as the pump has been running for a little while. When the pump is off it will drift towards air temperature, or higher if in direct sunlight.

Can you describe in more detail what is happening that leads you to suspect problems with the sensor?

 

[tmas]

Normally, a sensor mounted in that way will be quite accurate at measuring water temperature as long as the pump has been running for a little while. When the pump is off it will drift towards air temperature, or higher if in direct sunlight.

Can you describe in more detail what is happening that leads you to suspect problems with the sensor?

It's telling me the water temperature is 84 degrees when the actual water temperature is closer to 70, trust me. The air temperature at the time is in the mid 80s.

 

[JasonLion]

Normally a sensor like that has a small probe that sticks into a hole drilled into the pipe. It is difficult to tell from the picture if that is what you have or not. If the sensor is simply clamped to the outside of the pipe it could do what you describe.

 

[tmas]

Normally a sensor like that has a small probe that sticks into a hole drilled into the pipe. It is difficult to tell from the picture if that is what you have or not. If the sensor is simply clamped to the outside of the pipe it could do what you describe.

Thanks. I will check the sensor tonight. I didn't install it...

 

[bobby1017]

Mine is exactly like that, as long as the pump runs it's accurate, otherwise the water in the pipe warms or cools to near air temp. If you cover it to shield the sun and it's still wrong then maybe the sensor is bad.

 

[Poolsean]

You can try putting Air conditioner insulation foam around the exposed sensor portion, clamped to the pipe. As Jason said, when water is flowing through the pipes, it should read your water temp fairly accurately. Since it's between the pump and filter, you may also have debris or a scale build up over the temperature sensor sticking in the pipe.
You can also try removing it and putting a piece of rubber to seal the hole, and putting the sensor in a cup of ice cold water to see if it changes temperature readings to match your cup of ice water, if it's still 14 degrees off, or if it stays at 84 degrees.

 

[ps0303]

I had one of these telling me the pool was 144! Come to find out the pump basket was filled with leaves so the flow of water was limited causing the pump to actually heat up the water in the pump basket. Cleaned the pump basket and it dropped over 20 degrees but the damage had already been done. Had to replace the sensor.