What is the 'cover method' for AC cleaning? Explain it to me step by step
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I keep reading 'cover / collection bag cleaning' from companies, but nobody explains what it is. I have a 12,000 BTU Gree in the living room, block in Colentina, 3rd floor, white furniture and parquet under the unit. I want to understand exactly what happens in my home before I let anyone use pressurised water on an electrical appliance on the wall.
What is really happening
The method exists because the only proven way to remove biofilm from the evaporator and roller is mechanical washing – detergent, brushing and pressure rinsing, with over 99% reduction of fungi – and a split cannot be carried to the sink. The cover turns the wall into a washing area. The electrical part (control board, motor) sits on the right of the unit under a cover; we isolate it with film and never aim the jet there; the power is off. What ends up in the bucket is exactly what you were breathing: the water is black at first and clear at the end, and that is the finishing criterion, not the clock.
- The area and sensitive components are protected before work.
- The cover collects wash water.
- The hose directs water into a container.
- Washing with alkaline detergent, brushing and high-pressure rinsing reduces fungi inside the unit by more than 99%. [Indoor Air, 2023]
- The blower (cross-flow fan) is the most fungus-contaminated component of a split unit, more than the filter or the front of the evaporator. [Indoor Air, 2023]
- EPA principle: mould must be physically removed, not merely 'killed'; biocides are not recommended as routine practice. [US EPA, 2024]
- The condensate pan of household units had the highest bacterial load (~12,300 CFU/cm²), over 20 times the 500 CFU/cm² limit for public spaces. [Frontiers in Public Health / PubMed Cent, 2024]
What we do on site
- 1. We switch the unit off at the breaker. We remove the front cover and filters; we photograph the evaporator, roller and pan.
- 2. Foil on the floor and the furniture under the unit; the unit's electrical box is isolated with film.
- 3. We fit the double-layer waterproof cover: it clips onto the casing, the top edge is sealed to the wall with tape and clamps, the bottom mouth has a 2 m hose led into the white bucket.
- 4. We apply the alkaline detergent to the evaporator (full depth), the roller and the pan; contact time 5–10 minutes.
- 5. We wash with the adjustable-pressure washer: medium pressure on the fins, along their direction; low pressure on the roller, which we turn by hand to reach every blade; the pan and condensate hose until clear water runs outside.
- 6. We apply the sanitising solution to the clean surfaces; we wash the filters at the sink.
- 7. We remove the cover (the water is in the bucket), wipe, reassemble, run 'Fan' to dry, then 'Cool' and check together: temperature, drain, noise, smell. We show you the bucket with clear rinse water. See current rates on the Prices page.
What you can do yourself
- Clear 1 m under the unit and leave us a socket and access to the sink.
- Look at the bucket at the end – it is the best quality control.
What NOT to do
- Do not accept water washing 'without a cover, we'll be careful' – on units above furniture there is no 'careful'.
- Do not try it at home with a bin bag and a garden hose; sealing to the wall is the hard part.
Prevention
With this method, once a year is enough for a living room; between visits, filters and 'Fan'.
When to call us
0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; Colentina is 20 minutes away.
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The information on this page is educational and based on cited sources; it does not replace medical advice. We do not do repairs, installation or refrigerant circuit work.