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Bathroom Fitting

Toilet cistern slow to fill

Installed a Duravit 0910100005 Happy D Toilet some yrs ago in a 2nd floor flat. Ever since, the cistern never filled very fast & the plumber at the time wasn't able to solve it. Cistern is replenished from the lead tank in the bathroom in the ceiling cupboard. I found the shut off valve that feeds the cistern & tried to turn it, but I think the thread is worn - didn't make any difference anyway. Do I need a plumber to replace the shut off valve to free up the pressure, defur the pipes, or fit a pump to give it extra pressure or something...Looking for an expert to help me finally resolve it. Thx.


Many thanks to Sovereign Plumbing & Heating, Briner & Sons, and Cleverly Building Contractors for taking the time out to answer my question.

I have taken the cistern fitting out a few times in case it was grit causing a blockage, gently cleaned what I could, then flushed it thru with good pressure from the bath cold water tap, fed from the mains. nfortunately it did not solve the problem. It did let me see that the flow of water into the cistern is weak.

I will try to look for the float valve next as suggested. This does sound like a possible root cause. The pressure on the cold water taps fed by the mains is fine, powerful. If I can close off the shut off valve, I will then follow your instructions and see if this solves it.

If not, then it sounds like you are both right, it is a modern toilet just not compatible with a gravity fed water supply, and get a new float valve fitted that is compatible, and better still, connect it to the mains and get a new shut off valve fitted at the same time.

You are all very kind and I appreciate you taking the time out to help others. I will be sure to pass on the kindness and lend a hand to someone else in need I can help...One good turn deserves another! I hope you have a great Christmas and Happy New Year.

5 Answers from MyBuilder Bathroom Fitters

Best Answer

all ball valve inlets are provided with options for gravity (your system) or mains fed ,i do advise you to check the shut off valve is fully open,so only an experieced plumber can help you .you could always conect it to the mains water.


Answered 12th Dec 2011

try cleaning the fitting you may have grit in the washer which may have been disturbed when fitted


Answered 12th Dec 2011

Sometimes the float valve on a toilet has a flow restrictor inside where the pie attaches to it under the loo itself. You would locate it by isolating the toilet and then removing the pipe at the bottom. It usually stick out like a small plastic pin. Pull it out with pliers (it should be a corkscrew shape). This flow restrictor is fitted as standard as most houses are on mains pressure. You have gravity fed water so it does not need the flow restricting. If it is not this and the pressure is okay on cold taps in the bathroom then I would have a plumber round to investigate.

Some times float valves in modern toilets are not compatible at all with gravity fed. In that case you could have a new float valve fitted which is compatible.


Answered 12th Dec 2011

Hi, Edina

As suggested in some of your other replies the float valve in your toilet cistern may have a flow restrictor in it which can be easily removed by isolating the valve, removing the feed pipe under the cistern and withdrawing the resrictor with a pair of long nosed pliers from inside the float valve feed.
if this dosen't completely fix the issue you will need to call in a plumber to check for resrictions in your pipework.

Regards Cliff.


Answered 14th Dec 2011

Indirect water pressure can be poor. Change to mains pressure and move on with your life !


Answered 9th Jun 2019

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