Maintaining solar powered water heaters

Maintenance for domestic solar hot water heaters

Much like all systems, solar powered water heaters, and they're major design components, will require some periodic maintenance. And at some point, some parts of the solar domestic water water heater may eventually require repair or even replacement. 

A great deal of the periodic maintenance can be preformed by the system owner themselves. Other tasks, especially repair and replacement, may very well require the craftsmanship of a local solar energy contractor.

• Maintaining solar panels and collectors
• Inspecting water pumps in active designs
• Inspecting heat exchangers in closed loop designs
• Inspecting antifreeze heat transfer fluids
• Water heater maintenance; maintaining solar storage tanks

Basic maintenance for all systems and designs

Before servicing a solar hot water heater, it's strongly advised to reference the manufacturer's owners manual. All SRCC certified and rated solar domestic water heaters come equipped with outlined maintenance guidelines and schedules.

With that said, these basic maintenance recommendations can be applied to all solar powered water heaters, regardless of the manufacturer or system design.

Solar Panel and Collector Care

• It's always a good idea to periodically have the surface of the panels or collectors cleaned. A dirty surface will compromise the thermal performance and efficiency of the panel. 
• The structural support mechanisms of your solar hot water panels should be periodically inspected for potential structural integrity flaws. The nuts and bolts that make up the collector or panel mount and tilt should always remain tight and well secured
• The glass covering, or collector glazing, should be checked periodically for cracks as well as seal imperfections. With both evacuated tube collectors and flat plate collectors, the glass can be checked for frost. Hazy or frosty glazing is an indication that a seal has been compromised. More times than not, the panel will require replacement or repair.

Temperature Pressure Relief Valve On The Panel

A temperature pressure relief valve is an important safety feature that should be installed at the outlet of your solar hot water panel, with the exception of some drainback solar domestic water heaters.

• Faulty pressure relief valves usually remain stuck open or closed. When inspecting a valve, the lever should be lifted. This should release fluid from the solar water panel .
• If the fluid does not flow steadily outward when the lever is lifted, this usually indicates that the valve requires replacement. Always remember to gently lower the lever back to it's original position after inspection.
• Some solar powered water heater manufactures recommend testing the pressure relief valve as often as every six months. We recommend that you reference your system's owners manual.

Maintaining active solar powered water heaters

Since active solar water heater designs contain more moving components, it's no surprise that these systems generally require additional periodic Maintenance. Just about all the previously outlined maintenance recommendations apply for these solar powered water heaters, these additional procedures should be periodically preformed as well. 

Solar Water Pumps

• Periodically check to verify that the pump is activating during the peak sun light hours. Even the quietest of pumps make a slight noise when activated.
• If the water pump is malfunctioning or it refuses to activate, either the differential thermostat control or the PV module or even the pump itself requires repair and possibly replacement.
• Replacing a solar water pump is not an incredibly extensive task. But even for the most mechanically inclined, repairs and electrical wiring should be reserved for a local solar energy contractor.

Solar Heat Exchanger

A solar heat exchanger is designed to last for several years. But overtime cracks can develop, which in return causes fluid leaks. A leak may also cause the heat transfer fluid and the domestic water to mix. 

Most closed loop solar water heating systems use non toxic antifreeze solutions. So in the event a leak occurs, the contamination of domestic water won't be of real concern. But the overall efficiency of the domestic solar hot water heater will be compromised if a leak in the heat exchanger develops overtime.

• Whether your solar domestic water heater has an external heat exchanger or an internal heat exchanger will determine how simple and quick an inspection can be preformed. 
• With external double wall solar heat exchangers, leaks are very easy to detect. Often times locating the heat exchanger is all that's required.
• A DIY inspection would not be advised if the heat exchanger is immersed in the storage tank. It's best to consult a local solar installer for inspection.

Antifreeze Heat Transfer Fluid

Prolonged heat exposer is the arch enemy of any solar heat transfer fluid, With that said, the antifreeze solution in closed loop solar powered water heaters should be periodically checked and changed.

• The easiest way to determine if an antifreeze heat transfer fluid requires replacing is by inspecting it. A dark shade of brown is usually a clear indication that the fluid requires changing.
• Your local solar installer can use a chemical litmus paper to test the PH balance of the antifreeze in the solar loop. If the PH balance is 7 or lower, most solar water heating contractors recommend changing the fluid.
• If your considering a DIY fluid change, it's always wise to replace the fluid with the same solution that the manufacturer of the solar domestic water heater recommends. Antifreeze solutions in solar powered systems contain anti corrosion additives that protect the important copper components within the system.

More on solar hot water heaters

• Solar Hot Water Heaters; a complete and informative overview.
• Solar Water Heater Designs; passive and active systems, open loop and closed loop systems.
• Solar Water Heater Plans; whether you're considering a DIY installation or you're tailoring a design, important additional components will be required.
  
  
• Solar Hot Water Panels; integrated collector storage, flat plate collectors and evacuated tube collectors.
• Hot Water Solar Panels; the mount and tilt of the collector is important. These physical and performance specifications are important as well.
  
  
• Solar Hot Water Tanks; along with the back up source, storage tanks allow the system to provide hot water rain or shine and day or night.
• Solar Hot Water Pump; is used to distribute and circulate fluid throughout the system. Pumps are required in active systems.
• Solar Heat Exchanger; this system component provides a substantial amount of freeze protection and is required in some designs.
  
  
• Sizing a solar hot water heater correctly.
• A detailed overview of the federal solar tax credit and other incentives.
• How a solar domestic water heater is rated.
• How to find a reputable solar installer in your area.