Replacing a toilet syphon
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Turn off the water supply to the cistern using the isolation valve on the supply pipe, or the main stop tap.
Flush the toilet to empty the cistern, then soak up remaining water with a sponge.
Disconnect the cistern from the toilet pan (two wing nuts under the rim) and the water supply. Lift the cistern off.
Undo the large nut at the base of the syphon inside the cistern and remove the syphon.
Fit the new syphon — they're sold by height (9", 9½", or 10.5" are common). Reconnect the cistern and water supply.
Turn the water supply back on and check for leaks. Test flush several times.
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