Pentair Suntouch shows alternatively ON/OFF

[RobMot]

Hi everyone,

I have a solar heated pool with a “Pentair Suntouch” control panel. Recently I noticed that when I set temp lower than water temp, the Pentair shows “Water 80/70F SOL OFF”. And the Jandy Valve moves to SOL OFF position. It is great. While when I set temp higher than water temp, Pentair shows “Water 80/90F SOL ON/OFF”. It shows alternatively “SOL On” and “SOL OFF”. The Jandy Valve moves towards to SOL ON position when the panel displays “SOL ON” and the Jandy Valve stops moving when the panel displays “SOL OFF”. Eventually the Jandy Valve moved to SOL ON position.

Do I need a new Pentair Suntouch? If not, how can I fix this problem? Thanks a lot in advance if someone can help!

 

[ajw22]

Welcome to TFP.

I think your system is operating normally. The solar valve is being turned ON or OFF based on the temperature sensor by the solar panels.

If you have a problem with the cycling you may have a bad Solar Temperature sensor.

Solar Pool Heaters - Further Reading

www.troublefreepool.com

 

[RobMot]

Thanks ajw22!

I measured the Water and Solar temp sensor a moment ago. The resistances were 5.29 K and 10.73 K. They are corresponding to temp 104F and 74F. These were almost exactly what Suntouch showed. Both resistance readings were steady. Can you think of anything else that might cause Suntouch display “ON/OFF” cycling?

BTW, I set Suntouch "Solar Only" Mode. Am I right? If I turn it to "pool/spa" mode, the Suntouch shows "Low 88/92F SOLAR". I do have roof solar. I do not have SPA.

Thanks again!

 

[ajw22]

Let’s get @Dirk who has a solar setup to comment.

 

[Dirk]

So sorry, I have no experience with the Suntouch. To be clear: is this new behavior? Was it working differently, correctly, some time ago? And now it's not?

If that's the case, then something broke. You could try calling Pentair tech support. Maybe this is a known issue. Or you could start swapping in new parts. The sensors are the cheapest. Buy one, and swap it for the one that measures water temp. If no change, then swap it into the roof position. If no change, buy a new Suntouch from a source that will accept a return, and try that. Basic troubleshooting technique.

A sensor is about 20 bucks. The controller is around $300. There's one on eBay for $150, with a 30-day return policy. That's probably cheaper than a service call from a local pool guy.

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Apologies, I don't have a "Oh, I know exactly what that is" for ya.

 

[RobMot]

Thank you both so much! @ ajw22 @ Dirk
My pool has a local pool guy for weekly cleaning and service. So, I am not familiar with Pentair controller. In the past one month, the pool water was kept at 86F every day. (It sounds to me the controller working normal?)

Last week someone in my family wanted to have a warmer pool. So, I tried to raise the temperature on Suntouch. (Hope I did not screw up the setting?) Then I noticed that the water from jets was not warm. The Suntouch showed me “Water 102F/90F". But I am pretty sure the water was about 86, not 102. So, I called my local pool guy. He said the water temp sensor was bad, need to be replaced. After the sensor was replaced, I noticed the “SOL ON/OFF” display cycling. (I am not sure before the sensor replacement, it displayed “ON/OFF” cycling or not). My local pool guy said I need a new Suntouch.

The bad sensor is really bad. The resistance reading at room temperature (75F) corresponds to about 95F. While the new sensor is good.

I called Pentair technical support for why "ON/OFF" cycling display. The answer was I need a professional guy to come to check.

Today I set the Suntouch to "pool/spa" Mode. (It was "Solar Only" Mode before). When I set temp higher than water, Suntouch showed "SOLAR" and the Jandy Valve moves to SOL ON position. If I set temp lower than water, the Suntouch no "SOLAR" displayed. The Jandy Valve moves to SOL OFF position. In "pool/spa" Mode, I have nothing to complain about. Maybe "Solar Only" Mode is incorrect to me?

 

[Dirk]

Sorry Pentair was of no help. I sometimes call a vendor back when that happens, to try and get some other tech support person. Or even a third time. The idea is to stumble on to someone that knows your particular issue, instead of one trying to rack up calls-handled per hour.

I just don't know enough about Solartouch to advise anything else. Though it sounds like your pool guy doesn't know much more than I do about it! You can check the manual for the difference between the modes. It's online:

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/automation/solartouch/manual/SolarTouch_Solar_System_Quick_Reference_Guide_English.pdf

 

[RobMot]

Thanks Dirk,

It is a good idea. I will try Pentair tech support again.

I do have Suntouch 92 pages INSTALLATION AND USER'S GUIDE. But I was still got lost.

Thank you again for your help!