The condensate hose goes into the bathroom trap and 'gurgles' – it smells and blocks
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Militari, Roșia Montană street, 1980 block. The installer 4 years ago ran the condensate hose of the 12,000 Gree into the bathroom sink trap. In summer the sink gurgles and the bathroom smells stale. Last year it blocked twice too. Is that a good solution? What is yours to fix and what is not?
What is really happening
Condensate from an unsanitised unit is not clean water: it carries biological sludge from the pan – the most bacterially loaded component – and biofilm fragments from the evaporator. Poured into the sink trap, the sludge settles in the trap's bend and narrows it, hence the blockages; when the hose is pushed below the water seal, sewer air rises through the hose (the gurgling) and gases reach the pan and the unit's grille (the smell). Both problems improve massively once the pan and evaporator are clean – the water that leaves is clear and no longer deposits. The connection itself is an installation matter: above the water seal, with its own condensate trap or a check valve. EPA requires free drains and clean pans; the rest is a plumber's.
- Water forms on the cold coil during cooling.
- The pan collects it.
- The hose carries it to the designed drain.
- 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]
- EPA requires condensate pans to be clean and drain lines unobstructed; standing water must be fixed immediately. [US EPA, 2024]
- The 'dirty sock' or musty smell from an air conditioner comes from volatile organic compounds produced by microbial biofilm on the evaporator and blower. [Current Microbiology, 2000]
- Professional cleaning of split-unit components substantially reduced bacterial and fungal counts on all measured components. [Frontiers in Public Health / PubMed Cent, 2024]
What we do on site
- Collection cover; we clean the pan and remove the sludge – the source of the trap deposits.
- Cleaning solution on evaporator, roller, pan; pressure wash in place.
- Hose flushed along its full length, down to the trap, with clean water until it runs free.
- Sanitising solution along the whole route.
- Outdoor unit, washed in place.
- We show you how the connection is made and tell you what to ask the plumber for. See current rates on the Prices page.
What you can do yourself
- Pour a litre of clean water through the removed filters onto the evaporator once a month – it flushes the hose and refills the water seal.
- Sink trap cleaned every 3 months.
- 'Fan' before shut-off, filters every two weeks.
What NOT to do
- Do not pour caustic soda into the trap with the condensate hose connected – the fumes rise through the hose into the unit.
- Do not block the hose with a plug 'so it does not smell' – water comes out on the wall.
- Do not redo the connection yourself – ask the plumber for a condensate trap or a check valve.
Prevention
Annual sanitising and a monthly litre of clean water through the evaporator – the trap no longer blocks and the bathroom no longer smells. A correct connection is a single plumber visit.
When to call us
0764 012 943, Monday–Saturday 08:00–20:00. Militari.
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Read also
Sources (8)
- pmc.ncbi.nlm.nih.gov/articles/PMC11350112/
- www.epa.gov/mold/brief-guide-mold-moisture-and-your-home
- www.epa.gov/indoor-air-quality-iaq/should-you-have-air-ducts-your-home-cleaned
- www.ncbi.nlm.nih.gov/books/NBK143947/
- link.springer.com/article/10.1007/s002840010120
- link.springer.com/article/10.1007/s002849900435
- pmc.ncbi.nlm.nih.gov/articles/PMC6968652/
- onlinelibrary.wiley.com/doi/10.1155/2023/8984619
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.