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, overheating, and protects the solar system from aggressive water. Additionally, our DBS version is the higher end version because it's completely maintenance free. There's no vacation mode, or anything required. It's plug and play, set it and forget it.

The solar storage tank is fabricated of 316L Stainless Steel instead of a typical enamel lined water heater that only lasts about 7 years (because the warranty is 6 years). The Stainless Steel tank has a 10 year warranty, but is designed to last a lifetime.

The solar should provide for about 80-90% of your hot water needs, but there is one 4500w backup heating element located in the top 1/3 of the tank for inclement weather.
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 80gallons. 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.

Pressurized Glycol systems use a variety of techniques to try and mitigate the damage caused by overheating; including pressure relieve valves, expansion tanks, and heat dumps. All of these strategies present challenges in the operation and maintenance of the solar hot water system; therefore if you elect to use a pressurized glycol be sure your solar contractor provides a written plan for operation and maintenance including the strategy for overheat protection.
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.
The only component prone to failure in the solar loop of a drainback system is a pump. The pump typically requires replacement every 7-10 years.

There are multiple components in the solar loop of pressurized glycol systems that are prone to failure: air vent, pressure gauge, pressure relief valve, check valve, and an expansion tank. These components have a short design life and need to be replaced frequently during the 30-50 year design life of a solar hot water system.
With a drainback system, if a component fails, the solar fluid (approximately 5-6 gallons) will simply drain back into the reservoir. If the system uses an eagle sun controller it can only fail in the off position and therefore prevents damage to the rest of the system.

On a glycol system, if a pump fails the glycol will overheat causing the expansion tank and pressure relief valve to be compromised and both components will need to be replaced. If not corrected immediately, the glycol will continue to acidify eventually compromising the other components in the system including piping and collectors.
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.
An EagleSun System is designed to last 30 - 50 years.

Let Alternate Energy Technologies (AET) help you go solar with our solar thermal collectors, storage tanks and systems brought to you by the name you can trust.