SolarTouch not turning solar off at target temp

[Ryano2121]

I have a SolarTouch system. I have it set so it does not control the pump, cooling and freeze protection are off.

I have noticed lately that the solar is running all day so I started watching the temps today.

I had the target temp at 80* and the water temp was 80* with the solar running. I turned the target temp down to 79* and the solar shut off. But 15 minutes later the solar came back on and when I looked at it the target temp was still 79* and the water temp 80*.

Any idea why this would not be shutting the solar off when it reaches the target temp?

 

[pooldv]

No, that is weird. Do you have the differential set at 3 or 4. Maybe that will help. Have you powered if and back lately? That might fix it.

 

[Ryano2121]

I should have said that the air temps have been in the 90's so the solar temp is well over the differential.

I'll try cycling power tomorrow.

 

[Pool Clown]

Give it more than 1 degree before you determine that it has a problem. IIRC, if it is set to 80, it will heat till it hits 81, then rotate the valve. Turn it down to 75 and see if it stays off.

 

[Ryano2121]

According to the manual, it should shut off at the target temp, not one degree above. However, I let it go up another degree and it still didn't shut off. The only way to get it to shut off is to turn it down one degree.

 

[chiefwej]

Like a thermostat for a furnace of AC unit there is a tempratore differential. Do you want it to turn on at 79 and off at 80? That's impractical so it will allow it to drop below the set point and shut off slightly above, like any heating device.

 

[Ryano2121]

No, I want it to heat to the target temp and turn off. The SolarTouch provides the water temperature, which I have confirmed with a thermometer in the pool. When the water temp on the SolarTouch matches the target temp, according to the manual it should turn off.

The reference to 79 is just an example. If the water temp says 80 or 81 and the target temp is 80, the solar stays on. If I turn the target temp down a degree, the solar will turn off. But then it will come back on, even though the water temp is equal to or greater than the target temp.

 

[Pool Clown]

In an attempt to find out if this is a differential problem, or a control problem.

In your post you say when you turn the set point down, it turns off. But have you ever left the control alone to see if it turns off, by itself? if so, what temp, or, what was the water temp to set point difference?