A scored solar preventive maintenance checklist for residential and commercial systems: system information, production against expected, monitoring alerts, array condition (soiling, cracked glass, hot spots, delamination, snail trails), racking and roof attachments, wiring and connectors, inverters with error codes and ventilation, combiners and disconnects, optional thermography, cleaning, battery storage, an issues log with photos and actions, and sign-off.
Site and System Information
Which system, what kind of visit, and who is doing it.
Visit title
System owner or client
Site address
Your company
Technician
Visit date
Site type — Residential, Commercial rooftop, Community or utility-scale, Agricultural, Other
Kind of visit — Scheduled preventive maintenance, Annual inspection, After a storm or event, Follow-up on a monitoring alert, Warranty visit, Other
System size (DC)
Year installed
Inverter make, model and number of units
Monitoring platform or site ID
Date of the last maintenance visit
Weather during the visit
Site contact on the day
Were the open items from the last visit all closed? — Pass, Fail, N/A
What failed, and where exactly?
Site and array overview
Production and Monitoring
Is it making what it should, and what has it been reporting?
Period compared
Expected production for the period
Actual production for the period
Actual as a percentage of expected
Where the expected figure came from — Weather-adjusted model, Original design estimate (typical year), Same period last year, Monitoring platform estimate, Other
Is production acceptable for the period and the weather? — Pass, Fail, N/A
What failed, and where exactly?
Is monitoring communicating, with every inverter and module-level device reporting? — Pass, Fail, N/A
What failed, and where exactly?
Alerts and fault codes since the last visit
Has every alert since the last visit been explained or resolved? — Pass, Fail, N/A
What failed, and where exactly?
Monitoring screenshots — production chart and alert list
Array Visual Inspection
The modules themselves: clean, intact, and with nothing living under them.
Soiling level — Clean, Light dust, Moderate — visible film or droppings, Heavy — production affected
Is all module glass intact — no cracks, chips or shattering? — Pass, Fail, N/A
What failed, and where exactly?
Are modules free of visible hot spots — browning, burn marks or scorched cells? — Pass, Fail, N/A
What failed, and where exactly?
Are modules free of delamination, bubbles or milky patches? — Pass, Fail, N/A
What failed, and where exactly?
Are cells free of snail trails or other discoloration? — Pass, Fail, N/A
What failed, and where exactly?
Are backsheets and junction boxes intact where you can see them — no cracking, chalking or lifted boxes? — Pass, Fail, N/A
What failed, and where exactly?
Are frames undamaged and module edges sealed? — Pass, Fail, N/A
What failed, and where exactly?
Is it clear under the array — no nests, leaves or debris? — Pass, Fail, N/A
What failed, and where exactly?
Is the array free of new shade — tree growth, new structures, equipment? — Pass, Fail, N/A
What failed, and where exactly?
Array condition — each problem with its row and position
Racking and Roof Attachments
What holds the array down, and the roof around it.
Are clamps and fasteners tight on a spot check, with torque marks unbroken? — Pass, Fail, N/A
What failed, and where exactly?
Are racking, rails and hardware free of corrosion or galvanic damage? — Pass, Fail, N/A
What failed, and where exactly?
Are rails, splices and end caps intact and in line? — Pass, Fail, N/A
What failed, and where exactly?
Are flashings and seals at attachments intact, with no lifting or cracked sealant? — Pass, Fail, N/A
What failed, and where exactly?
Is the roof covering around and under the array in sound condition? — Pass, Fail, N/A
What failed, and where exactly?
Is the roof free of leaks below the array (attic or ceiling checked where possible)? — Pass, Fail, N/A
What failed, and where exactly?
Are foundations, piers and posts sound — no heaving, settling, erosion or rust at the ground line? — Pass, Fail, N/A
What failed, and where exactly?
Is vegetation under and around the array under control? — Pass, Fail, N/A
What failed, and where exactly?
Are fencing, gates and warning signs intact? — Pass, Fail, N/A
What failed, and where exactly?
Racking, attachments and roof
Wiring and Connectors
Everything that carries DC from the modules to the inverter.
Are conductors still secured and off the roof surface, with no sagging runs? — Pass, Fail, N/A
What failed, and where exactly?
Are conductors free of chafing, UV cracking or rodent damage? — Pass, Fail, N/A
What failed, and where exactly?
Are connectors fully mated, with no heat discoloration or melting? — Pass, Fail, N/A
What failed, and where exactly?
Are conduit, fittings and penetrations intact and sealed? — Pass, Fail, N/A
What failed, and where exactly?
Are grounding and bonding connections intact and free of corrosion? — Pass, Fail, N/A
What failed, and where exactly?
Wiring and connector problems
Inverters
One entry per inverter: status, codes, cooling and condition.
Inverters
Inverter name or location
Serial number
Status on arrival — Producing, Producing — derated, Fault showing, Off or no display
Error or event codes
AC output when checked
Ventilation, fans and heat sink clear? — Pass, Fail, N/A
Enclosure sealed and undamaged, no water or pests inside? — Pass, Fail, N/A
Terminals free of heat damage (where opened by a qualified person)? — Pass, Fail, N/A
Firmware version
Display and label
Are all optimizers or microinverters reporting, with none failed? — Pass, Fail, N/A
What failed, and where exactly?
Inverter notes
Combiners, Disconnects and Panels
The boxes between the array and the grid.
Are combiner boxes dry, sealed and free of corrosion, pests and heat damage? — Pass, Fail, N/A
What failed, and where exactly?
Are string fuses intact and of the correct rating? — Pass, Fail, N/A
What failed, and where exactly?
Do the DC and AC disconnects operate smoothly and lock? — Pass, Fail, N/A
What failed, and where exactly?
Were accessible terminations torque-checked or scanned, with none loose or hot? — Pass, Fail, N/A
What failed, and where exactly?
Does the rapid shutdown initiator work, with the array voltage dropping as it should? — Pass, Fail, N/A
What failed, and where exactly?
Are labels and placards still present and legible? — Pass, Fail, N/A
What failed, and where exactly?
Is the working space in front of electrical equipment clear? — Pass, Fail, N/A
What failed, and where exactly?
Combiners, disconnects and labels
Thermography
Optional: a thermal scan of the array and the electrical equipment.
Did you do a thermal (infrared) scan on this visit?
Camera used
Irradiance during the scan
How it was scanned — Handheld from the roof, Handheld from the ground, Drone, Equipment only
Were modules free of hot cells or hot diodes beyond your threshold? — Pass, Fail, N/A
What failed, and where exactly?
Were connectors, fuses and terminals free of abnormal heating? — Pass, Fail, N/A
What failed, and where exactly?
Largest temperature difference found
Thermal images with matching visible photos
Cleaning
If you cleaned, how — and proof it made a difference.
Was the array cleaned on this visit?
Method — Soft brush and water, Water-fed pole, Robotic or machine, Rinse only, Other
Water used — Deionized or purified, Softened, Tap, None
How much was cleaned
Was the cleaning done in a way the module manufacturer allows — no abrasives, no high pressure, no harsh chemicals? — Pass, Fail, N/A
What failed, and where exactly?
Before cleaning
After cleaning
Battery Storage
Optional: the battery and its backup function.
Is there a battery on this system?
Is the battery area clear, ventilated and protected, with no damage or swelling? — Pass, Fail, N/A
What failed, and where exactly?
Is the battery free of active alarms? — Pass, Fail, N/A
What failed, and where exactly?
State of health, if reported
If tested, did backup transfer work? — Pass, Fail, N/A
What failed, and where exactly?
Battery and gateway
Issues Found
Every problem, where it is, what you did, and what is left.
Issues
What is wrong
Where
How serious — Safety — make safe now, Repair needed, Monitor, Fixed on this visit
Action taken — Fixed on this visit, Made safe — repair needed, Return visit needed, Quote to send, Warranty claim, Monitor only
Parts used or needed
Photo — before
Photo — after
Summary and Sign-Off
How the system is doing, what happens next, and who agrees.
How the system is doing overall — Good — no action needed, Fair — minor items open, Poor — repairs needed, Unsafe — made safe or shut down
State the system was left in — Producing normally, Producing — part of it isolated, Shut down
A scored solar preventive maintenance checklist for residential and commercial systems: system information, production against expected, monitoring alerts, array condition (soiling, cracked glass, hot spots, delamination, snail trails), racking and roof attachments, wiring and connectors, inverters with error codes and ventilation, combiners and disconnects, optional thermography, cleaning, battery storage, an issues log with photos and actions, and sign-off.
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Found work that needs a crew? After a repair or a re-roof reinstall, the scored QC and commissioning walk has its own form: Solar installation checklist
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A solar maintenance checklist records one preventive visit to a system that is already producing: whether it is making the power it should, what the monitoring has been complaining about, and what you found on the roof, in the wiring, at the inverters and in the disconnects. It works for a home system checked once a year and for a commercial array on a quarterly round. Every check is Pass, Fail or N/A, issues get their own entry with a photo and the action taken, and the report shows the owner exactly what changed since last time. Fill it in here and download a PDF, or speak while you walk, and the document writes itself.
Start with production, not the roof
Before you climb anything, compare what the system produced since the last visit with what it was expected to produce for that period and that weather. A system running ten percent low tells you where to look: a string that tripped, a failed optimizer, heavy soiling, a new shade source, an inverter derating in the heat.
The form asks you to type the expected and actual figures, the period, and the percentage, and then to make one judgement — acceptable or not for the conditions. The engine does not calculate the percentage; the number you type is the one the owner sees.
What to look for on the array
Most module problems are visible if you know what you are looking at. Soiling and bird droppings shade cells and cost production. Cracked glass lets water in. Brown or burned spots and discolored cells point to hot spots. Bubbles or milky patches are delamination. Thin dark lines across cells, often called snail trails, can indicate micro-cracks.
Each has its own check, so the report says which problem was found rather than a single "modules OK". Photograph each one with something in frame that identifies the row and position.
Thermography is optional, but powerful
An infrared camera finds hot cells, failing bypass diodes and overheating connectors or terminals long before they are visible. It only works with enough sunlight on the array, so the form asks for the irradiance and the camera used, and the section stays hidden unless you say you did a thermal scan. Many commercial O&M contracts call for one each year; on homes it is usually done when production is unexplained.
Issues found: what was fixed and what is left
Every issue gets its own entry: where it is, how serious it is, what you did, parts used, and a photo before and after. An issue fixed on the visit is still recorded, because the next technician needs to know a connector was replaced or a breaker reset. Anything marked as safety, repair or monitor appears in the summary of findings, so the owner sees the open items without reading the whole report.
Common questions
How often should a solar system have preventive maintenance?
Many residential systems are checked once a year or after severe weather, and many commercial systems quarterly or twice a year, often with one annual thermal scan. The right interval depends on the system, the climate, the warranty terms and any service contract, so check those first.
Should solar panels be cleaned on every visit?
Only when soiling is costing meaningful production. Clean with methods the module manufacturer allows — usually soft brushes and clean, low-mineral water, never abrasives or high pressure — and record before and after photos. The cleaning section only appears if you say you cleaned.
Can this checklist be used for commercial systems?
Yes. The inverter section is a list, so you add one entry per inverter, and the combiner and disconnect checks cover larger systems. Mark items that do not exist on a small home system as N/A and they are left out of the score.
What is a good production ratio?
It depends on how the expected figure was produced. Compared with a weather-adjusted model, a healthy system usually lands close to the expected value; compared with a typical-year estimate, a cloudy month can read low without anything being wrong. Record where the expected number came from so the comparison makes sense next time.
Who should do solar maintenance?
Visual checks and monitoring reviews can be done by trained technicians. Opening combiners, disconnects or inverters, torque checks on live equipment and thermography should be done by qualified electrical workers with the right protective equipment, following your company's safety procedures.