By Matthew Baring-Gould, Kingscliff-based drainage plumber. Servicing Tweed Heads for 4 years. 5.0 stars across 173 Google reviews. Licensed NSW 383340C and QLD 15036450. ABN 74 605 392 348.
Historical case study from Matty’s archive. A Brisbane commercial kitchen with a blocked disconnector gully outside the house, during winter. Classic fat-in-the-trap problem that comes back every cold snap unless you change how you use the sink.
What was wrong
All waste water from the kitchen runs through a line that ends at a disconnector gully outside. The gully has a trap on it. In normal conditions, hot water from the sink flushes through continuously and keeps everything moving. In winter, as the pipe cools and the fat lands at the trap, it solidifies at the first bend. The trickle of water from a running sink is nowhere near enough to flush solid fat. It builds up, the trap closes off, and the kitchen cannot drain.
Why winter specifically
Fat cools faster in cold weather. The line between kitchen sink and gully is often underground or on an exterior wall, which is colder than the kitchen itself. By the time the fat reaches the trap, it is already past its solidification point. Summer heat keeps it liquid long enough to flush through; winter does not.
What we did
- Opened the gully.
- Hydrojet in from the trap end (that first bend is usually where the fat builds up).
- Hot water flush assist, same as any fat job.
- Pushed the broken-down fat down the main line, out to the council sewer.
- CCTV confirmed clear.
The free prevention advice
We tell every commercial kitchen customer the same thing after a job like this: once a week or once a fortnight, fill both sinks with hot water, add a splash of dishwashing soap, and pull the plugs so both drain at once. The volume of hot soapy water flushes through the line at a rate that fat cannot resist. It is far more effective than running a trickle through the day, and it costs nothing. Do this routinely and the trap stays clean through winter.
Call Matty on 0447 188 394.
Customer names and addresses have been withheld. Individual results vary. Drain Masters Plumbing is licensed in NSW (383340C) and QLD (15036450).
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