When I flush my toilet I get a Foghorn sound for a few seconds what causes this ?

Probably worn water supply fill valve if the unit has aged.

Hi anon the toilet probably needs the syphon changing. The syphon causes the push down the pan for the solids to go.

toilet will need syphon replacing. the lid should lift of the cistern, some have the push buttons screwed down to the syphon and to remove them just turn the ring around them anti-clockwise.

internal syphon needs re placing not costly

i would think the syphon is not closing after the flush, so as the cistern fills it just runs straight into the pan. you'll need to replace the syphon...

Hi, if you remove the cistern lid and flush the toilet, look at the float (back left) to see if this is rising freely when the water fills back up. Once the water has stopped filling, check the fill level lines on the large syphon in the middle of cistern. Your model of toilet has an eco flush which will be lowest line to save water, so not as much water will flush out. There is a long plastic screw on the float (back left) which you can turn to adjust the water level to the higher line on syphon (1.6 gallon flush) and turn it slowley till the water level reaches that mark. flush a couple of times to see it is filling back up to the set amount.

Sounds like your toilet is not vented properly. Possilbly something caught in the trap is causing it to syphon

The shut off valve depends upon where your plumber fitted it and whether one was installed at all. If there's not one near the cistern then you'll need to find the stop valve which is on either the main household cold water tank outlet or if the cistern is filled directly by mains water then you'll need to turn off the main supply valve or even the valve in the street.

The fault is caused by a failed syphon assembly inside the cistern. Although it's possible to remove the faulty part and replace it the sheer number of different syphon assembly designs and the age of many of them usually mean that it's quicker and simpler to replace the entire assembly. Without knowing exactly which make and model of syphon you have it's impossible to give you any more specific details as the operating methods vary so widely, but if you're mechanically minded then you may well find that you can dismantle the old syphon and locate the failed seal. Sometimes all you need to repair them is an old car tyre inner tube and a pair of scissors. A repair often costs pennies and takes hours, a complete replacement syphon assembly often costs between £13 and £60 depending on the model and design (plus labour) but usually takes no more than around fifteen to twenty minutes to replace if the cistern is close-coupled to the toilet and a bit longer if it's an old-fashioned high level cistern with restricted access.

Given the need for guesswork based on the limited details in your question I hope that you appreciate my reply and ask only that you return the favour by rating my answer.

Hi,

This is caused by the 'syphon' mechanism sticking, quite often nowadays the 'brilliant' plastic push button/ syphon combo sticks, and most toilets are fitted with an internal overflow, lift the lid on the cistern and check for anything causing an obstruction.

More often than not, it's a tiny bit of scale that causes such a headache, and the fact that nothing is made with any quality nowadays!

If you can't see what's wrong call a plumber, he/she will solve it.

I hope this helps

Steve