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Solar Hot Water

Operation and Maintenance

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Periodic inspections and routine maintenance will keep your solar hot water system running efficiently and for a long time. While the overall system can last over 40 years with proper care, active systems have electrical and mechanical parts that will need repairing or replacement before then. Active systems also require more frequent maintenance than passive systems because of the need to check pumps, heat exchangers, temperature sensors, etc. Passive systems are not recommended in cold climates.

Step 6: Installation section suggests sources for finding qualified companies and contractors. These professionals may also conduct system inspections and perform maintenance tasks. Ask your system provider what is required and be sure to read the owner’s manual.

It is recommended you hire a licensed and/or certified contractor, but if you plan on doing the work yourself, the following Inspection List gives you an idea of what is involved for an inspection (taken from the U.S Department of Energy’s Energy Savers website).

Collector shading
Visually check for shading of the collectors during the day (mid-morning, noon, and mid-afternoon) on an annual basis. Any shading can affect performance.

Collector glazing and seals
Look for cracks in the collector glazing, and check that seals are in good condition. If excessively yellowed, plastic glazing may need to be replaced.

Plumbing and wiring connections
Look for fluid leaks at pipe connections. Most leaks occur immediately after installation. All wiring connections should be tight.

Piping, duct, and wiring insulation
Look for damage or degradation of insulation covering pipes and wiring.

Roof penetrations
Flashing and sealant around roof penetrations should be in good condition.

Support structures
Check all nuts and bolts attaching the collectors to any support structures for tightness.

Pressure relief valve
Make sure the valve is not stuck open or closed.

Verify that distribution pumps are operating. Listen to see if they come on when the sun is shining on the collectors after mid-morning. If you can’t hear the pump operating, either the controller or pump has malfunctioned.

Heat transfer fluids
Antifreeze solutions in liquid solar heating collectors need to be replaced periodically. It’s a task best conducted by a qualified technician. If water with a high mineral content (i.e., hard water) is circulated in the collectors, mineral buildup in the piping may need to be removed by adding a de-scaling or mild acidic solution to the water every few years.

Storage systems
Check storage tanks for cracks, leaks, rust, or other signs of corrosion.


National Renewable Energy Laboratory (produced) for the U.S. Department of Energy. (2003, December). A Consumer’s Guide: Heat Your Water with the Sun. DOE/GO-102003-1824.

U.S. Department of Energy. (2010, October). Solar Water Heating System Maintenance and Repair. Retrieved January 25, 2011, from: http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12950