What should go on the roof-access card?
Five lines, laminated, on the inside of the access door. Check seals for cracks and wipe the lip. Pre-wipe the pane. Mount, watch the pump for 10 seconds, then start. Anchor the tether to the eye, not the frame. Rinse pads flat and log the cycle.
That card does more for pad and seal life than any training session, because it sits where the operator is standing. We have seen facilities cut pad replacements by roughly a third just by adding the pre-wipe line, which costs nothing and takes ninety seconds per bay.
Add the stop conditions too: glass surface above 35 °C, wind above 8 m/s on an exposed roof, and any pane with visible damage near a frame. Those three are the situations where a routine job becomes an incident.
Key Takeaways
- Pre-wipe loose grit; 3–6 g per m² of sand pressed into a pad is what scratches low-iron glass.
- Replace the seal lip at 12–18 months regardless of appearance — hardened rubber leaks under load.
- Anchor the tether to structure, never to a window frame, above head height.
- Above 200 ppm TDS the spray leaves film; above 400 ppm you get visible scale.
- Rinse pads flat, never folded wet — creases become streak lines.
Five steps in a window cleaning robot user manual get skipped most often: the pre-wipe of loose grit, the seal-ring seating check, the tether anchor point, the water hardness limit, and the end-of-cycle pad rinse. Each one costs you either seal life or glass cleanliness, and skipping them is why pads wear out in 18 cycles instead of 50.
We have watched this on a dozen installs. Reading the manual is not the problem; manuals bury the critical items in a maintenance appendix instead of the first page. Here is the order that matters.
What does the pre-wipe step actually prevent?
Grit. A dry microfibre pass over the pane before the robot runs removes most of the sand and construction dust that would otherwise be pressed into the pad and then dragged across the glass. On a rooftop skylight near a road, that pass removes roughly 3–6 g of grit per m². Without it, that grit grinds the pad’s fibre and, if any of it is silica, scratches the glass.
The manual usually says ‘remove loose debris’. It does not say the consequence. Scratches on low-iron glass are permanent and visible at grazing angles, which on a customer-facing atrium is the thing the client notices first.
How do you check the seal ring is seated?
Wipe the lip with a damp cloth, then mount the robot and watch the pump for 10 seconds. A correctly seated seal pulls the machine flat against the glass with a visible squeeze of the lip on all four sides. A seal with a dry spot or a nick will pull unevenly, and the machine will run with a bias — usually drifting toward the weak corner.
Replace the lip at 12–18 months regardless of appearance. Rubber hardens from UV and ozone, and a hardened lip leaks under load even when it looks fine. Seal kits run $40–90. The machine that drops off a pane because of a $50 part is the most expensive outcome in this article.
Why does the tether need its own anchor?
The tether loop on a consumer machine is designed to catch the unit, not to survive a shock load. If you are working above head height, anchor to structure — a rail, a fixed eye, a rated bracket — not to the window frame or a furniture leg. The manual will mention the tether; it will not tell you the frame is inadequate.
On a roof, this becomes a genuine safety question. A 5 kg machine falling 8 m onto a stairwell or a car park is an incident report. The Lingkong K3 review shows the dual-anchor arrangement used on machines built for skylight work, which is what a consumer machine lacks.
What is the water hardness limit?
Most manuals specify filtered water and stop there. The number that matters is total dissolved solids. Above roughly 200 ppm, the spray leaves mineral film when it dries, and the film builds faster than the pad removes it. Above 400 ppm, you get visible scale within three or four cycles on dark glass.
Use distilled or RO water if you can, or add a cheap inline filter. On a large skylight array, a $120 filter cartridge pays for itself in avoided acid washing.
How should the pad be cleaned between cycles?
Rinse it under running water, wring it, and hang it flat to dry — not folded. Folded pads keep a wet crease line that becomes a dirt channel and then a streak line on glass. Most pads last 40–60 cycles on routine domestic use, 20–35 on rooftop dust.
The mistake we see most often is putting a used pad back on the machine wet. Bacteria and odour are minor problems; the real cost is that a wet pad with trapped grit cures against the glass in sun and leaves a bonded residue.
Who actually needs to read the manual twice?
Anyone using the machine above 3 m, anyone on a glass roof rather than a window, and anyone cleaning more than once a month. For a household using a machine on two bedroom windows four times a year, a skim is fine — the failure modes take longer to appear than the usage.
If you are running machines commercially, the better move is a one-page laminated card on the roof access door with the five steps. Nobody rereads a PDF on a roof. The skylight robot review hub has the site-specific notes for the models people actually deploy.
What should go on the roof-access card?
Five lines, laminated, on the inside of the access door. Check seals for cracks and wipe the lip. Pre-wipe the pane. Mount, watch the pump for 10 seconds, then start. Anchor the tether to the eye, not the frame. Rinse pads flat and log the cycle.
That card does more for pad and seal life than any training session, because it sits where the operator is standing. We have seen facilities cut pad replacements by roughly a third just by adding the pre-wipe line, which costs nothing and takes ninety seconds per bay.
Add the stop conditions too: glass surface above 35 °C, wind above 8 m/s on an exposed roof, and any pane with visible damage near a frame. Those three are the situations where a routine job becomes an incident.
Key Takeaways
- Pre-wipe loose grit; 3–6 g per m² of sand pressed into a pad is what scratches low-iron glass.
- Replace the seal lip at 12–18 months regardless of appearance — hardened rubber leaks under load.
- Anchor the tether to structure, never to a window frame, above head height.
- Above 200 ppm TDS the spray leaves film; above 400 ppm you get visible scale.
- Rinse pads flat, never folded wet — creases become streak lines.