placement of solar (air) sensor for solar heated

[Diver]

I got PentAir SolarTouch controller for my upcoming solar heater and it came with 2 sensors - water and air. The first one is 20' and the second is only 20" - it barely sticks out of the controller, making its placing it very difficult.

Is it supposed to be exposed to the ambient air only, or does it have to be in the sun when the panels are in the sun? I assume the latter, in which can I'm puzzled by manufacturer's decision to make it so short.

 

[JamesW]

The water temperature sensor gets mounted in the pipe between the pump and filter. The solar temperature sensor gets mounted on a flat surface with the same exposure to the sun as the panels. Ideally, near the panels. Then, you use waterproof connectors to connect to a two conductor cable to get to the controller. Use 20 AWG outdoor rated sensor wiring.

 

[Diver]

James,

Thanks for your response. That makes sense, I just don't get why the manufacturer wouldn't include enough cable for both sensors...

 

[JamesW]

I agree. It would make sense for them to have enough wire for most installations.

 

[Diver]

It seems that both of the sensors are the same 10K Ohm thermistors, so it's even more strange the way PentAir packages it:

P/N 520272 - Temperature Sensor replacement kit (for water/air)
P/N 522101 - Solar Temperature Sensor replacement kit (for solar)

Is there difference between air and solar? The only difference that I see is that the solar one is black, so it would mimic closer what the panels would experience temperature wise (I think).

Seems like PentAir could've simply packed two of P/N 522101 but with 20 feet wires and it would work fine.

I don't need all 20 feet for the water one, so I think I'll cut the wire off of that one and extend the other one with it.

 

[Isaac-1]

It depends on the installation, for example my solar controller is nearly 50 wire feet from my solar panels so it makes some sense to use a pigtail sensor and add wire as needed. I used relatively cheap low voltage outdoor lighting wire (I think around 16 gauge)

 

[needsajet]

I found the manual for your controller at http://www.pentairpool.com/pdfs/solartouchOM.pdf

It sounds like the 20" is a pigtail and you supply the wire to get to the panels depending on your need. On mine, I needed 70' to put it in conduit and make it tidy.

There's a humorous line in the solar sensor section of your manual... "If necessary, splice a two-conductor extension wire to the sensor." I can't imagine an installation where 20" would be enough for to get to the roof sensor!!

 

[bdavis466]

The two sensors are exactly the same. The solar temperature sensor would ideally be located on the roof where the panels are located. In my situation that would require over 150' of wire which probably isn't practical for the manufacturer to provide.

There is no standard setup for pool equipment and solar heating so it isn't really possible to make something that would meet the needs of every pool.