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Clearing a blocked waste pipe

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Contents

Method

Blockages are mainly caused by hair being washed down plugholes in bathroom appliances. Larger debris blocks the kitchen sink and often the blockage is due to a build up of grease or fat in the pipe. Both these type of blockage build up gradually and the flow of water leaving the appliance becomes slower and slower. This is because the inside of the pipe is becoming increasingly smaller as the deposits build up over time. Regular use of chemical drain cleaners will help keep the waste system clear and smelling fresh, but remember to follow the instructions carefully.

If one of the appliances fails to empty when all the others do, the blockage must be in the vicinity of its branch pipes. Try using a sink plunger, remembering to block off the overflow with some wet rags. Make sure there is enough water to in the appliance to cover the cup of the plunger. Plunge vigorously for several seconds and then repeat the process until the blockage clears. Flush the pipes with clean water to remove any debris and disinfect to freshen and cleanse the area.

If the method fails try using a hand operated hydraulic pump. Block off the overflow with wet rags and fill the pump with water. Hold the nozzle over the outlet and a downward action on the tool forces a powerful water jet along the pipe to dislodge or disperse the blockage. If it still appears blocked, keep the tool in position and apply an upward stroke to create sufficient suction to dislodge the blockage. If the method fails the trap needs clearing. The trap is situated below the waste outlet. It is a bent tube, which is designed to hold water in order to prevent odours from the drain entering the room.

Brass or lead U traps

Old-style U traps are generally made of brass or lead and must be handled with care to avoid damage. Place a bucket or bowl underneath and using a wrench unscrew the cleansing eye at the bottom of the trap. Use a rod or bent coathanger to wire out any debris remaining. Rinse the sink with water to remove all debris from the trap. Clean the thread of the clearing eye, and before replacing, wrap some PTFE tape around it to prevent leaks. Run water through the system to check the connections are watertight.

Plastic U traps

Plastic U traps do not have clearing eyes, so it will be necessary to remove the trap. There are lock nuts either side of the trap, which should be unscrewed to release the trap. If they are reluctant in moving, try applying boiling water over the top, remember to have a bowl or bucket below. Before replacing wrap some PTFE tape around the locknut threads to prevent leaks. Run water through the system to check the connections are watertight.

Bottle traps

Bottle traps are the easiest traps to clear because the whole base of the trap can be unscrewed by hand. Once the debris has been removed from the trap, use a rod or metal coathanger to probe the wastepipe for any residue. Rinse the trap thoroughly and cleanse with disinfectant. Before replacing wrap some PTFE tape around the cover thread to prevent leaks. Run water through the system to check the connections are watertight.

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