General maintenance

Operation and maintenance (O&M) costs of each solar water heating system is estimated at ½ of 1% of initial cost per year. O&M is similar to that required of any hydronic heating loop and may be provided by site staff, with experts called in if something should fail. Regularly scheduled maintenance includes:

• Check the solar collectors and structure components for any damage. Note location of panel glazing or broken evacuated tubes needing replacement. Note any surface damage on absorber panel and that tubing containing heat transfer fluid is in good condition.
• Check tightness of mounting connectors. Repair any bent or corroded mounting components.
• Drain energy storage tanks for sediment removal.
• Check condition of heat transfer fluids.
• Determine if any new objects, such as vegetation growth, are causing shading of the array and remove them if possible.
• Clean outer surface of collector array annually with plain water or mild dishwashing detergent. Do not use brushes, any types of solvents, abrasives, or harsh detergents.
• Check all connecting piping for leaks. Repair any damaged components.
• Check plumbing for signs of corrosion.
• Check condition of corrosion inhibitors in heat transfer fluids and the state of the sacrificial anodes in the system.
• Observe operational indicators of temperature and pressure to ensure proper operation of pumps and controls.
• Observe that the collector heat transfer fluid pump is running on a sunny day and not at night.
• Use insolation meter to measure incident sunlight and simultaneously observe temperature and energy output values given by system controller. Compare the values with original efficiency of system.
• Check status indicators provided by system controller. Compare indicators with measured values.
• Document all operation and maintenance activities in a workbook available to all service personnel.
• Check proper position of all valves.
• Flush entire piping system to remove mineral deposits every 10 yrs.

A more through checklist can be found in the Solar Energy Use Chapter of the ASHRAE Handbook — HVAC Applications.