Suction cups are the failure point on any skylight cleaning robot. Inspect them every job, replace them every 6 to 12 months on regular use, and keep them clear of grit. A single nicked cup can drop holding force by half and turn a routine clean into an emergency.
Maintenance on these machines is not complicated, but it is unforgiving. The parts that touch glass wear fast, and the parts that fail without warning are usually the ones nobody checks. Here is what to look at and how often.
When should you replace suction cups?
Inspect before every job. Wipe the cup sealing edge with a damp cloth, look for nicks, flat spots and embedded grit, and check for hardening. UV and heat age the rubber, so a machine stored on a hot roof ages faster than one kept indoors.
- Daily: wipe the sealing edge, remove grit, check for cuts.
- Monthly: measure holding force at the rated slope, compare to the spec.
- Every 6 – 12 months: replace the set on regular commercial use.
- Immediately: any cup with a nick, tear or visible hardening.
Cost is modest. A replacement cup set runs a small fraction of what a service call costs, and dragging a job because a cup failed wastes an operator day on top.
How do brushes and squeegee blades wear?
Soft brushes last longer than stiff ones on coated glass, and they scratch less. On a site cleaning 4,000 m2 a year, expect soft brush filaments to need replacement around 8 to 14 months. Squeegee blades wear faster because they run wet against grit. A blade with a rounded edge leaves streaks the operator cannot fix by pushing harder.
Match brush to glass: soft for coated and tinted panels, medium for plain toughened glass, never a stiff abrasive pad on low-E coatings. On the Lingfeng S1 with its tighter panels, brush changes are quicker, which matters when one machine covers several roof types.
Why is the water filter the most overlooked part?
A clogged filter drops flow and pressure, so the brush runs drier than it should and leaves dirty water on the glass. The result looks like a cleaning failure but is really a filter problem. On humid sites with heavy pollen, clean the filter weekly, not monthly.
Hard water is a related trap. Cleaning with unfiltered tap water at 300+ ppm hardness leaves mineral spots that reappear as the water dries. Use filtered or deionised water on visible glass, and the filter is what protects the finish, not the brush.
What maintenance stops a job cold?
- A suction cup that loses seal mid-slope, forcing an emergency retrieval.
- A blocked filter that leaves streaks and a repeat visit.
- A battery that no longer holds its rated runtime, cutting the day short.
- A worn squeegee that smears water across a fresh pass.
None of these are exotic failures. All are preventable with a simple check sheet and a spare-parts box kept on site. The teams that run robots well treat them like any plant: daily checks, monthly measurements, honest replacement intervals. The teams that struggle usually skipped the daily check.
How do you store a skylight robot between jobs?
Storage decides how long the cups and battery last. Keep the machine indoors, out of direct sun, with the cups clean and ideally with the sealing faces protected from dust. A machine left on a hot roof or in a cold shed ages its rubber and stresses its cells. A simple locked store with a charging point near the roof access will outlast any premium part upgrade.
Batteries want a partial charge, not full or empty, if the machine sits for weeks. Lithium packs stored flat lose capacity, and packs stored at full charge in heat lose it faster. For a machine that works seasonally, plan a monthly top-up to around half charge and it will hold its runtime for years rather than one season.
When should you replace rather than repair?
Repair parts while the machine is reliable; replace the machine when repairs start eating the schedule. If you are calling out a technician more than twice a year on a machine past four years old, the downtime cost has overtaken the repair saving. Track cost of ownership, not just the repair invoice.
The point is not age, it is reliability. A well-stored machine doing light duty can run six or seven years with routine part swaps. A machine on daily commercial work may be ready for replacement at three. Judge it on downtime and finish quality, and let the numbers, not the calendar, decide.
What does a spare-parts kit look like?
Keep a simple box on site so a wear failure does not end the day. At minimum: one set of suction cups, two squeegee blades, a spare brush, a sediment filter, and a fuse where applicable. That kit covers the failures that stop jobs most often and costs a small fraction of a service call plus a lost operator day.
Pair the kit with a one-page check sheet the operator signs before and after each job. The sheet is what turns maintenance from a memory into a record, and it is the first thing a warranty claim or an audit will ask for. Cheap to run, and it pays back the first time a cup fails mid-slope.
Key Takeaways
- Inspect suction cups every job; replace the set every 6 – 12 months.
- Soft brushes suit coated glass and last 8 – 14 months on moderate use.
- Clean water filters weekly on humid, high-pollen sites.
- Streaks usually mean a clogged filter or worn squeegee, not a weak brush.
- Keep spare cups, blades and a filter on site to avoid a dead day.
Need wear parts or a maintenance interval chart for your machine? Reach the team through the contact page.