Questions to Ask a Contractor
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Maintaining Your Solar System
PV systems are a very durable and reliable source of renewable-energy since they have little or no moving parts, degrade at a very slow rate, and can offer a life expectancy of approximately 20 plus years. A standard factory warranty for modules is usually 20 years though some manufacturers may offer longer warranties. The warranties for PV inverters may be different from the modules and you would need to check with the manufacture for their specific warranty durations.
PV system maintenance is generally simple. Modules should be kept clean of dust. In areas of little rain the arrays should be cleaned periodically with mild detergent and water. When cleaning your modules be aware of damaged equipment. Never stand on or touch PV modules and their metal racking. If you see damaged equipment, safely walk away, shutdown the PV system, and call a professional. Shading from new plant growth is another cause of ill performance for an array and so systems should be checked for potential shading issues and corrected.
The PV array wiring should also be checked occasionally to make sure that it remains securely fastened. As most PV arrays are roof mounted and high voltages may be present, safety is a primary concern when performing maintenance and we recommend that a professional perform this work. An annual inspection by trained professionals is recommended to check for safety and performance issues, such as loose wires, corrosion and UV breakdown of components.
Solar Water Heating Maintenance Considerations
While many people feel solar hot water is maintenance free, this is not the case. Solar water heating systems are also very durable and have a life-expectancy of 15 plus years. The water heating panels typically have warranties of 10 years and the water storage tank of 5 years. As with PV modules, solar water heating panels need to be kept free of dust and shading for the greatest efficiency. The piping insulation should also be checked for decay and repaired or replaced as necessary. In addition, the water storage tank has an anode rod in it that helps to protect the tank from galvanic action and should be replaced every 3 to 5 years. A complete system inspection can also prevent failure and ensure peak performance of the other components. For example, a leaking safety valve will not only reduce the amount of hot water available, but it will also increase your water bill.
Most residential PV systems are fixed as either flush mounted or tilted on a roof. There are no moving parts on a residential PV system. The only maintenance normally required is to periodically clean the modules. Most PV systems come with a production monitoring system that allows you to see the current production of your PV system. If any significant drop in production has been noticed, it is likely some type of soiling on the module has occurred. Periodic maintenance should also include checking for debris buildup under and around the array, condition of wiring, and security and weather-tightness of fasteners.
What happens during and after a power interruption - what should I check?
All PV systems in the United States must comply with UL1741, which is a guideline for utility interconnection. PV systems MUST shut down in the event of a power interruption to protect utility workers from electrical hazards. While the DC production of your solar modules will continue to function during the day, a power interruption will cause the AC output of the inverter to cease operation. Most inverters include highly advanced technology that analyzes the existing connection to the grid. These inverters detect the stability of the grid and will connect and / or disconnect from the grid as needed. When the grid is found to be stable, they will resume operation without the need of any homeowner interaction. If you have a web-based monitoring system or have a system display for your PV system, it's always a good idea to check the system if it is operating properly when power returns after a power interruption.
PV System Warranties
There are usually many warranty components to your PV system:
- Installer warranty (typically varies between 1-10 years)
- PV Module Warranty (typically varies between 5-10 years on the model and 20-25 years on production)
- Inverter Warranty (typically varies between 10-25 years, depending on the technology)
- Racking system warranty (typically varies between 5-10 years)
- Roof warranty (typically varies between 1-5 years)
Prior to the installation of your PV or solar water heating system you should consider verifying the condition of your roof to insure that the roofs life expectancy will be close to the life expectancy of the system. Since a roof installed PV or solar water heating system is normally placed on roof penetrating brackets it is advisable to check that your roof warranty to make sure that the warranty will not be voided by the installation of your system.
Check with your insurance carrier to determine if your homeowner's or business insurance will cover your system. It is also advisable to ask your insurance agent if the installation of the PV system will affect any other policies such as water damage policies.
Most PV systems that are sized over 10 kW require additional insurance coverage for your home. This is to minimize the amount of risk between the utility and the power generation system on your home. Check with your home umbrella insurance carrier to see what costs are included with this coverage.
PV systems in rare cases can cause fires and kill an electrician. Systems must be installed and operated in accordance with the National Electric Code, County Building Codes, and Hawaiian Electric Standards. Only trained professionals should work on and touch the equipment. You must learn and know how to safely shut down the PV system. Adults and children should never touch or stand on the PV modules, metal racking, wiring, or any associated electrical equipment.