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Frequently Asked Questions

See commonly asked questions by homeowner related to solar energy solutions. 

There are many types of solar water heating systems, but the drainback is the most efficient indirect system on the market; it prevents from freezing, and overheating.  

The solar storage tank is fabricated of 316L Stainless Steel and comes standard with a 10-year warranty. 

A typical solar storage tank is larger than a conventional heater, because you can only harvest the sun during daylight hours. So by upsizing the storage tank, you can store the collected heat for night and early morning use. Our standard size for a standard 3 bedroom home is 80 gallons. We do have 120 gals available if you have a larger home and want to harvest as much of the sun as you can!

Yes, your contractor should give you a complete price; equipment and installation.  A site visit is usually required to verify roof space and pipe runs. The entire pipe run to the collector on the roof from the solar storage tank is insulated copper pipe. The ideal location for the solar collector(s) is on the south facing roof with little to no shading from 8-4 if possible. 

A drainback system uses a controller with temperature sensors to monitor the performance of the solar hot water system. When the tank reaches a pre-set temperature limit, the pump turns off and the heat transfer fluid (usually water) drains out of the collector into the drainback reservoir. By removing the solar fluid from the collector, there is no danger of overheating.


Drainback systems use the same strategy for freeze and overheat protection, a controller. If the temperature sensor at the collector is not approximately 8 degrees warmer than the tank sensor, the pump does not come on, which means no solar fluid will be in the collector during freezing temperatures.

When a glycol system is used, the concentration of glycol in the heat transfer fluid has to be carefully calculated to ensure it is high enough to survive the coldest possible temperature for that environment. 

Both drainback and pressurized glycol configurations are indirect or closed loop systems, which means there is a heat exchanger between the potable water and the solar fluid. All closed loop systems prevent new water or air from entering the collector, limiting the potential volume of minerals available to contribute to scaling to a very small concentration. These heat exchangers need to be large enough to provide sufficient heat exchange area otherwise the potable side of the heat exchanger can become scaled. 

A drainback system requires no maintenance beyond that of a regular water heater. Once or twice a year a garden hose is attached to the water heater to flush the scale from the bottom of the tank.

On a glycol system, the pH of the glycol should be checked annually and replaced along with the expansion tank when the pH falls below 7. There are several other components in the system that require inspection and testing to ensure optimal performance including pressure relief valves, check valves, and automatic air vents. Ensure your solar contractor provides a written maintenance plan or purchase a service contract if offered. 

With a drainback system, there is no need for a vacation mode.

With a gylcol system, the controller needs to be set to vacation mode or the vacation by-pass valve needs to be opened; depending on the overheat strategy used by the solar contractor. 

In addition to the standard manufacturers warranty for parts only on all EagleSun systems, you may purchase an optional extended parts and labor warranty for an additional charge. The extended warrany is provided by Service Net and covers both parts and labor for 5 years. This benefits both the installer as well as the homeowner and must be purchased with the equipment package. Please contact your Dealer for more information and ask for additional coverage on your system.

Systems have a design life of 20+ years.

Contact Our Experts

Give us a call at 1-800-874-2190 or fill out the form and our team will reach out to answer your questions as soon as possible.

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