All of our products can be shipped via UPS!
Automatic Controllers
Manual control means you have to turn a valve to send the water through the solar panels. Automatic means that the valve is turned mechanically using a differential thermostat, sensors and a motorized valve. If water is moving through the solar collectors when it isn't sunny enough to add heat to the water, then heat is being lost by the collectors and you are cooling the pool. Under manual control this means that you are going to lose heat by having solar on at the wrong times. Sometimes, that's okay. If this is a small investment for a small pool then the extra $450 or so may be better spent on more collector area to make up for the difference. When manually controlling a solar pool heater, normally you will cheat by simply setting the pool pump timer such that the pool pump only runs during the hours that the sun shines reasonably directly on the solar collector surface. If the weather changes or the pool gets up to temperature you have to turn the valve but at least you don't have to turn the valve every morning and evening.
Your pool may have a pool automation system already and it may even have the solar brain built in already. If so, all you need to add is a sensor on the roof that sees the same sun as the collectors and a motorized valve to complete the automation component of your solar heater. The key component that none of the solar differential thermostat control manufacturers have ever clued into is the fact that the sensor on the roof, AKA the sun sensor, should look like the solar panel. Pentair uses the same probe they use for the pool temperature sensor. Heliotrope uses an aluminum block which is better but still looks and behaves thermally - nothing like the collector. Many years ago we started making our own roof sensors. Our stainless steel sensors go right inside pieces of solar panel material so the sensor behaves just like the solar panel.
The way a differential thermostat works is with 2 sensors. These sensors are negative temperature curve 10K thermistors. That means that as temperature goes up their resistance goes down and vice versa. They are 10K ohms at roughly room temperature.
Heliotrope
In general, automatically controlling your solar pool heater makes sense. For 23 years we used the Heliomatic made by our friends at Heliotrope General. I can't say enough good things about Pat and John at Heliotrope. They had great service and a solid product. Their distributor JED Engineering, run by Jim Kron, is also top notch all the way. However, we moved away from their products in 2009 because we couldn't resist the Pentair Suntouch digital solar control system.
Pentair Suntouch
 Suntouch Controller |
 Three-Way Valve |
 Valve Actuator |
 Pump Relay |
 Roof Temp Sensor |
 Water & Air Temp Sensors |
We tested the Pentair Suntouch controller in the field for several years before making it our standard. It's actually a full pool automation system. It can control pool and spa valves, Intellichlor salt systems, Pentair VS3050 variable frequency drive pumps, waterfalls, lights and your pool pump. Yes, for an additional $60 relay, the solar controller is your pool pump timer. It's all digital and programmable. It's an easy add-on later of a 3HP solid state relay whereas with the Heliotrope product you had to buy the HM5000 with the 1HP mechanical relay instead of the HM4000 that doesn't have the relay. Even then with the non-digital differential thermostats, all that relay did was turn the pump on if it wasn't on when solar needed it on. You still needed a separate pump timer. The Pentair Suntouch is also fully field serviceable and Pentair has proven a worthy ally. We've had only one problem situation so far and they simply shipped the customer a new circuit board, no hassle. Click here to view the Suntouch user guide in PDF form on the Pentair website. Note: this is a large 6.9mb PDF file.
Freezing Issues
We used to promote the idea of the Floverter valve made by Heliotrope. It has no seals so the motor doesn't need to be as strong and it allows flow to drain down past the spool in the valve so when solar is off the feed pipe and the collectors can drain down. That is useful when the water level corresponding to the pressure in the system is lower than the height of the collectors and you're concerned about freeze damage to your rigid solar panels at night. Now that we almost never sell rigid solar panels in places where it freezes, we don't have to worry about this anymore. Powerstrips are flexible and can freeze full of water. The header pipes are stronger than the PVC the system is plumbed with so they generally do pretty well through even a hard freeze and if we have a big disaster you're just replacing a few headers. With a semi rigid polypropylene collector you're in big trouble. The little hole gave too many people false reassurance though. The hole doesn't mean the water drains down through it. The water only drains down to the level corresponding to the pressure. Sometimes the draindown capability makes sense and we can always take the positive sealing valve apart and drill a small hole through the spool so it drains down. One thing we like about the positive sealing motorized valves is the fact they are universal between the two major manufacturers and they are available everywhere and all pool guys recognize them and are comfortable with them. On the other hand, the Floverter valves are a solar industry specialty.
Now that you've been on the home page and learned all about which collector type is best for your situation and learned all about plumbing and auto controls on this page, you're ready to go to the sizing pages and learn all about what a solar heater can do for your pool. We've posted many regionally specific curves showing what you can expect in your area with verifiable proof. You will also find a form you can fill in so that I can give you my recommended sizing and a full quote.
If you'd like an education on solar heating in more general terms check out the pages here. I wrote them in 1995 when I first published this web site.