I have a pool solar water temp sensor question

chuckiechan

I have a Pentair LX220 solar controller. It's a comparator type - a "cold" sensor by the filter, and a "hot" one up top, and a dial to adjust water temperature.

I had the solar water system removed and replaced for a re roof. The controller isn't working right. When the water is running, the solar turn on OK, and the dial in the box works OK. But after it stops on it's own, it won't restart the system by only turning the dial. The installer guy is just not getting it and I'm not sure he knows what he's talking about. So I'm going to just fix it myself.

I suspect the reason is the installer put the roof temp sensor in the pipe down at the bottom of the roof system. Shouldn't this be outside the pipe in the sunlight? Diagrams I've seen show and "outside" sensor fastened to the outside of the pipe up high in the system in full sun.

My sensor is a type installed into a pipe, but I think it can be outside and work just fine.

Any advice for me?

Thanks in advance...

I'll drive you crazy with my electric roof solar estimate later... LOL

I'm glad to find such a site with all the solar areas grouped together!

solar_dave

Re: I have a pool solar water temp sensor question

My Goldline thermal solar has a sensor at the collector and at the storage tank. The delta between the 2 is adjustable as is the peak tank temp for controlling the pump.

I do think that was probably the intent. From here: http://www.pentairpool.com/pdfs/LX-220SolarControlIG.pdf

Solar Sensor
Install the other Temperature Sensor at the solar panel array, or any sunny location.
WARNING: DO NOT DRILL HOLE AND CLAMP SENSOR INTO SOLAR PIPE
. For
glazed panels, install Sensor between collector and glazing. Run 2-conductor cable between the
Sensor and the Solar Control. Use waterproof connectors (provided) to connect Sensor to cable.
At the Solar Control, strip insulation 1/4” and connect cable to the circuit board at SOLAR
SENSOR screw terminals.

chuckiechan

Re: I have a pool solar water temp sensor question

That's what I'm thinking. I think my is set up a little differently. The sensor I have appears to be the type to drill in to a pipe, then I'm going to put it at the top since when the solar is off, the pipe is empty and since heat rises, the sensor should get plenty of heat.

I don't see any reason the sensor has to be put into the pipe. It doesn't know it's not in water. I'll have to think about that.

I'll have to experiment.

BTW, your instructions attached were much better than the copy I found. Thanks for that!

Dave Angelini

Re: I have a pool solar water temp sensor question

You are correct the collector sensor is typically at the top of the collector under the insulation or in the pipe. The sensor is probably a thermistor and they do fail from time to time.

chuckiechan wrote: »

That's what I'm thinking. I think my is set up a little differently. The sensor I have appears to be the type to drill in to a pipe, then I'm going to put it at the top since when the solar is off, the pipe is empty and since heat rises, the sensor should get plenty of heat.

I don't see any reason the sensor has to be put into the pipe. It doesn't know it's not in water. I'll have to think about that.

I'll have to experiment.

BTW, your instructions attached were much better than the copy I found. Thanks for that!

chuckiechan

Re: I have a pool solar water temp sensor question

Dave Angelini wrote: »

You are correct the collector sensor is typically at the top of the collector under the insulation or in the pipe. The sensor is probably a thermistor and they do fail from time to time.

I'll be moving it. Probably to the top, but not inside the pipe. No point in drilling holes if I don't have to.

I plan to seal the old hole with a 1/2 a piece of pipe joint and glue. I'm just going to snap it over that part of the pipe and glue it. Will that work OK?

jcheil

Re: I have a pool solar water temp sensor question

chuckiechan wrote: »

I'll be moving it. Probably to the top, but not inside the pipe. No point in drilling holes if I don't have to.

I plan to seal the old hole with a 1/2 a piece of pipe joint and glue. I'm just going to snap it over that part of the pipe and glue it. Will that work OK?

I have done that before as a temp fix. Use a couple of hose clamps on it also. Apply the glue and crank the hose clamps down quickly. I just left mine on after it dried but I guess you "could" remove them if there is not much pressure in the pipe. Leaving them on gave me a (perhaps false) sense that it was a better repair

BB.

Re: I have a pool solar water temp sensor question

Put a little insulation around the pipe/sensor so that a cold breeze does not give you a false reading.

-Bill