Toilet filling up very slowly until bathroom tap is switched on

portabello_2

Hi all. We have an unusual problem with the toilet. After flushing, it fills up extremely slowly - until we run either the hot or cold tap in the bathroom at which point it fills normally and is ready to flush again.

Does anyone have any idea what might be causing this? Why would the two be connected? And how can we fix it? Thanks!

tony6403

Very odd! I would think that an airlock is unlikely particularly as you say that turning on the hot tap enables a normal refill.
Have you removed the cistern lid ,flushed and checked the movement of the ball valve.

SailorSam

You can see how the cold tap and the loo may come from the same supply pipe, but can't understand how the hot tap would.
The hot tap must be supplied from your copper tank in the airing cupboard is it ? Which in torn will be supplied from the tank in the loft, does the same outlet from the loft supply the loo ?
Then maybe where it comes out of the loft tank is sticking or bunged up.
Just a thought if it was sticking there and when water was only needed for the loo it came slowly but when extra water for the taps was needed it forced it's way past the sticky outlet in the loft.
I don't know that, it's just an idea .... check where the water comes out the tank in the loft ??????

grizzly1911

I would be surprised if the two were connected. Cold water then possibly.

I would have thought it was either a sticking ball valve hinge/valve mechanism or some form of blockage in the valve mechanism.

Lift the cistern lid, flush the loo. Does the ball valve actuating arm drop? As it is filling does depressing/moving the ball arm alter the flow?

portabello_2

Thnaks for your replies. Have just checked again and it does just seem to be the cold water taps (either the sink or bath) that have an effect on the toilet filling up. - not the hot water after all.

But the cold taps do definitely do make it fill when when run after flushing the loo. I can't see any movement inside the cistern - just a trickle of water coming out until the tap is turned on and the tank fills up normally.

Still puzzled!

grizzly1911

Increases by a lot or just a fraction?

Have you tied pushing the float ball down, that should increase flow.

If it or the valve itself is stuck faulty try wiggling it up and down to see if that makes any difference.

May need to replace valve mechanism, or at least bits in it.

portabello_2

Grizzly, when the cold taps are run, the trickle in the cistern stops and the toilet fills up normally in an instant as it should.

We once had a similar problem (but without the cold taps being involved!) and got a plumber who just replaced a tiny round, flat circle of rubber somewhere in the system. Do you know what this might have been? I can't remember but wondered if it's the same problem again.

grizzly1911

portabello wrote: »

Grizzly, when the cold taps are run, the trickle in the cistern stops and the toilet fills up normally in an instant as it should.

We once had a similar problem (but without the cold taps being involved!) and got a plumber who just replaced a tiny round, flat circle of rubber somewhere in the system. Do you know what this might have been? I can't remember but wondered if it's the same problem again.

Depends on the type of ball valve. If it is a plastic one they do have a rubber diaphragm in them, that flext back would and forward, opening/shutting that may be worn/stiffened. When you open up a local cold supply this could be giving more flow though/pressure differentiation making the diaphragm open more.

They are readily available in DIY places but it would me opening the vale assembly to replace.

karl-123

i am a retired plumbing teacher

it sounds as if you need a new side entry or bottom entry ballvale

unless you strip and clean your old one

turn off the mains
flush the loo
siphon or use a sponge on any remaining water in the wc cistern

remove and clean or replace ballvalve

be carefull when refitting metal backnuts when not corectly inline
with plastic threads can " cross thread " and destroy the ballvalve
i use rubber o rings on my 15mm wc tap conectors but normal red fibre washers with 2 wraps of ptfe will do bye karl

heating-eng

karl-123 wrote: »

i am a retired plumbing teacher

it sounds as if you need a new side entry or bottom entry ballvale

unless you strip and clean your old one

turn off the mains
flush the loo
siphon or use a sponge on any remaining water in the wc cistern

remove and clean or replace ballvalve

be carefull when refitting metal backnuts when not corectly inline
with plastic threads can " cross thread " and destroy the ballvalve
i use rubber o rings on my 15mm wc tap conectors but normal red fibre washers with 2 wraps of ptfe will do bye karl

Retired plumbing teacher in this one. You have had some jobs karl ?

jimmo

heating-eng wrote: »

Retired plumbing teacher in this one. You have had some jobs karl ?

Careful there, h-e.
You do realise our karl is a 6ft 4in skinhead who frightens debt collectors don't you?
https://forums.moneysavingexpert.com/discussion/comment/47747585#Comment_47747585