Shifting Blockages from Clogged Sinks


Most traps are easily dismantled, but gaining access to them is often more difficult. For this reason, it’s always worth trying to clear the blockage by simpler means. Plunging works best where there is a single appliance connected to the trap. Where there are several, such as a two-bowl kitchen sink with drainer hoses, it is less effective. Poking with coat-hanger wire or a sink auger works well on ‘U’ bends, less so on bottle traps.

Burning with caustic soda is very effective on blockages caused by build-ups of grease — but the chemical itself is highly dangerous and must be used with care.

Caustic soda can damage old lead piping but won’t harm plastic. Any water trapped in the fitting must be removed first (see Problem Solver – Problems with Sink Traps).

before plunging a trap1. Before plunging a trap, block up the overflow with a wet rag and fill the fitting to overflow level. This helps to create a good pressure build-up.

2. Using the largest possible plunger, place it over the waste outlet and work it up and down vigorously to build up the force of the push-pull effect.


Trade Tip

Making a sink plunger

"If you don’t have a sink plunger, try using an old plastic ball cut in half — or at a pinch, a large saucepan lid. Simply pump up and down over the waste outlet in a rapid succession of short, sharp strokes."


to use a sink auger1. To use a sink auger, begin by feeding it down through the waste outlet into the trap. Turn the handle as you go to help the screw past the blockage.

2. When you feel the auger move easily, withdraw it slowly turning the handle at the same time. With luck, the screw will carry the obstruction with it.



clearing metal sink trapsPlace a bucket or bowl under the trap to catch the contents.

♦ Unscrew the clearing eye by gently tapping on one of the lugs with a hammer and bolster — or similar wide-bladed tool. If the eye is tight, arrange some means of support to avoid placing strain on the trap.

♦ Hook out the obstruction with a piece of bent coat-hanger wire.

♦ Wrap a few turns of PTFE tape around the thread of the eye before replacing it, and take care not to over-tighten.



using chemicals to clear clogged sinksCaustic soda and other proprietary drain clearing products are extremely harmful to the skin, so always follow the manufacturer’s instructions. Wear gloves and some form of eye protection when using caustic soda, and keep the tin out of the reach of children.

Also, never mix household cleaning products (for example, bleach and lavatory cleanser) in an attempt to clear a trap. Some combinations produce a gas which is, quite literally, lethal.

24. May 2011 by admin
Categories: Plumbing, Sinks | Tags: , | Comments Off on Shifting Blockages from Clogged Sinks


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