Solar heater controller

I am new to the forum and looking for advice. I have a proposal to install a Heliocol solar heater, and the contractor is recommending an automatic heater controller. I live in Clearwater, Florida so I would think that it would be a simple task to get to the desired warmth and then off the solar heater in early Summer, then back on when cooler evenings return. The salesman said that our summer rains can actually cause the solar panels to cool the pool more than the added rain. What is the general opinion on this?

I'm not sure whether you'll get an informed answer or not, and I don't have the experience to know whether your salesman is correct or not.

But you can find out for yourself, easily enough:

1. Install accurate inline temperature gauges on BOTH your pool piping, upstream of the solar return, and also IN the solar return.

2. Check and compare temps under full sun, under clouds, in rain, and at sunrise, after clear nights. If you the solar return temp is often lower than the pool temp, you may need a controller of some sort, to prevent the panels from cooling the pool.

Something like this should work:

PIC Liquid Filled Thermometer Bottom Connection, Brass Well

Be careful about accuracy; a lot of commercial gauges have a 2 - 3 degree error, and in your application, that could cause problems. BUT . . . you don't actually have to have an accurate pair of gauges; just a pair that read alike. So compare them in water baths with both cool, warm, & hot water: if they read the SAME, even though they are both off by a few degrees, you're good to go, since you need difference readings, rather than absolute accuracy.

Membership upgraded; post moved to new section.

Having used solar panels for at least a dozen years I have LONG found that it's no big deal to turn the panels on and off manually. I have two ball valves, one for my south and eastern panels, and one for my north and western panels. THEORETICALLY, I could get better performance with robotic, computer controlled valves, but at what cost? If my pool gets too hot I merely turn the panels on at night and they act like a car's radiator, bleeding off heat energy.

Just, IMHO, it's over-kill.

If the panels are "off" they cannot either heat or cool the pool. You can use manual control as Carl suggests for both heating and cooling. Besides, here in Florida, the sun will heat your pool in summer, even with a screen enclosure. It's more likely you would want to use the panels to cool the pool at night during summer and to heat it during spring fall and winter.

But you should check for warranty issues. If the panels are off and drained of water, are there warranty issues? Without water or water flow will they get too hot and become damaged? Most panels discuss freeze protection for warranty coverage, but I doubt you have freeze issues.