Helio-matic solar controller. Is it supposed to do something?

[moore887]

Good evening,

I have this nice, well behaved 10,000 gallon uncaged pool next door to my house which I take care of. It's always been a warm pool but the owner thought the solar wasn't working. I've always had the solar valve open (not bypassed) by having the switch on the Helio controller set to test. When I put it to Auto the valve closes. Nothing I do with the knob on the controller makes the valve move. So I flicked the switch on the valve so that the valve turned to open to solar. The pump runs form 10:30am to 5:30pm. I thought the controller might only be useful if the pump was running all the time and the owner wanted to cool the pool at night. Is this true?

 

[ajw22]

I would test the resistance of the temperature sensors connected to the green block on the lower right. My guess is one or both are reading wrong.

https://www.aetsolar.com/literature/Manuals/TempVsResistChart.pdf

Temperature Sensors - Further Reading

www.troublefreepool.com

 

[moore887]

Thanks Allen. Time for me to blow the dust off my multi-meter. If the solar is just used for heating the pool is the automation valve and controller even required or is it imperative that works to open and close the valve in accordance with the temperature on both sensors?

 

[ajw22]

Thanks Allen. Time for me to blow the dust off my multi-meter. If the solar is just used for heating the pool is the automation valve and controller even required or is it imperative that works to open and close the valve in accordance with the temperature on both sensors?

If you want the pool to stay at a selected temperature based on the knob temperature setting then the solar controller needs to know the pool temperature and solar collector temperature to modulate using the valve.

 

[moore887]

...and final question... What if you wanted the pool to be at the maximum available temperature? I ask because I have seen a couple of solar installs with no sensors or automation and just a manual bypass valve up the wall.

 

[ajw22]

Well at night when the solar temperature is less then the pool temperature with no controller you will lose heat; with the controller the valve should close and the pool will not lose heat from the solar system.

 

[moore887]

Would that still be the case if the pump is off at night? I suppose it might depend on the temperature of the residual water in the collector when the pump turns on unless it all drains down when the pump turns off.

 

[ajw22]

Would that still be the case if the pump is off at night? I suppose it might depend on the temperature of the residual water in the collector when the pump turns on unless it all drains down when the pump turns off.

If the pump is off you will not lose heat. But take the example of an overcast day. There will be times when the pool will lose heat to the solar if there is no controller.