Tosot ceiling cassette water leak repair — Redwood City

Air Conditioner Water Leak Diagnosis and Repair

A customer contacted us after noticing water leaking from a ceiling-mounted Tosot air conditioning system. Water leaks are one of the most common HVAC service calls during the cooling season, and while many homeowners assume the problem is related to refrigerant loss or a major mechanical failure, the actual cause is often connected to the condensate drainage system.

During our diagnostic inspection, we found that the condensate drain line had become restricted by accumulated debris and moisture-related buildup. As the air conditioner removes humidity from indoor air, condensation is produced and must be safely discharged through the drain system. When the drain line becomes partially blocked, water backs up inside the unit and eventually begins leaking into the living space.

Accessing the affected components required partial disassembly of the ceiling cassette unit. Unlike standard wall-mounted mini split systems, cassette-style air conditioners are installed within the ceiling cavity and require additional labor to reach internal components. During the inspection, the decorative panel was removed and the drainage assembly was carefully examined. The condensate pump was tested and confirmed to be operating properly.

After identifying the source of the issue, the drain line was thoroughly cleaned and flushed to restore proper condensate flow. The entire drainage system was then tested under operating conditions to ensure water was being removed efficiently and that no additional leaks were present. Following successful testing, the unit was reassembled and returned to normal operation.

✅ Water leak source identified
✅ Drain line professionally cleaned
✅ Condensate pump operation verified
✅ Drainage system tested and confirmed operational
✅ Air conditioner returned to normal performance

Tip for homeowners: If you notice water dripping from an indoor air conditioning unit, do not delay service. Even a small leak can lead to ceiling damage, drywall deterioration, mold growth, and costly repairs. Regular maintenance and periodic drain line cleaning can help prevent unexpected leaks and keep your HVAC system operating efficiently throughout the cooling season.