Leaking Cistern

Have you ever had the annoyance of a cistern that never stops running into the toilet bowl? It’s very irritating and it wastes a lot of water. Happily, its not to hard to fix and no too expensive either. Below are step by step instructions but remember if it all sounds too much for you Able Handyman Services will be happy to come and do it for you.

Inside your toilet system there is a thing called a siphon which controls the deluge of water that falls into the bowl when you pull the flush. When these wear out, and they do, they can let that steady trickle of water run through.

Toilet siphon

Toilet siphon

 At B&Q a new siphon will cost about £15 at Toolstation it will cost you £4.44.While your getting this, get a new doughnut washer as well if the toilet is close coupled.

Tools you will need are:

Pump pliers

Pump pliers

  1. A medium size phillips screwdriver
  2. A medium size flat head screwdriver
  3. A pair of pump pliers like those shown above
  4. Ordinary pliers
  5. Adjustable spanner

Changing the siphon step by step:

  1. Turn off the water supply. If you are lucky there will be an isolation valve on the inlet pipe to the toilet as shown below. This will have a screw head in the middle. Use a flat head screw driver to turn the screw head to 90 degrees to the direction of flow to isolate the supply. If there is no isolation valve you will need to turn off the main stop cock which is a tap you will find in a variety of places around the house. Most likely it will be out in the road outside you house or under the sink. Top tip: If you don’t know where your stop cock is, it’s worth finding out. If you have a burst pipe you’ll want the water turned off as quick as you can!
  2. Flush the toilet to empty the cistern.
  3. On a closed coupled toilet, these days most are, you will need to completely remove the cistern.
  4. Disconnect the water inlet and if there is one, the overflow pipe. These will be located on the bottom of the cistern either side. This is done by unscrewing the fixing nuts.
  5. Unscrew the scews fixing the cistern to the wall.
  6. Unscrew the wing nuts fixing (see below) the cistern to the toilet pan. The cistern should now lift off.
  7. Remove the old ‘doughnut’ washer which sits between the pan and cistern. It is best to replace this as re-using the old one can often cause leeks.
  8. Unscrew the large plastic nut on the outflow of the cistern using the pump pliers.
  9. Remove the old siphon and replace with the new one taking care to get the washers in the right sequence.
  10. Reassemble the cistern, fix back in place and reconnect the water supply taking care to seat the fibre washer in the pipe connector.
  11. Turn on the water supply and check for any leaks.

Isolation valve

Isolation valve
Wing nut

Wing nut fixing cistern to pan


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