Toilet filling when taps are turned on

Jeepers_Creepers

That blue colour is familiar - I've certainly seen that before. I bet someone on here will ID it :-)

The good news is that, since you have a flexible hose fitting, the replacement doesn't have to be exact. In fact pretty much any will fit.

The tricky bit of replacing these valves is when you have fixed pipework, so the new valve's threaded section that goes through the bottom of the cistern has to be the exact same length as the old one. You won't have that issue.

So, fill your boots - any valve will do.

Do you know if the cold supply to the cistern is from a tank in the loft or direct from the mains? What sort of boiler do you have - a combi?

Elmer_BeFuddled

Just got to say, generally, aren't people helpful on here. 

Alanp

I would also say it’s the fill valve, easy to replace so long as you can isolate the water, a couple of things, I use a length of clear plastic hose to syphon  the water from the cistern , and , when you fit the new fill valve, there’s a rubber gasket, usually tapered which goes on the inside of the cistern taper side down, don’t overtighten the locknut, hand tight and a quarter turn will do, ( ok maybe a bit tighter but it doesn’t need anymore) , plenty of vids on yt, it’s fairly basic to do...

Jeepers_Creepers

I was hoping to recommend a particular brand, but a glance at the reviews suggest that even Fluidmaster and Flomasta are fraught with issues.

https://www.screwfix.com/c/heating-plumbing/fill-flush-valves/cat831618?cm_sp=managedredirect-_-plumbing-_-toiletsyphon

I guess you just have to go for one, and rely on SF's excellent warranties.

I'd look for (a) a brass threaded whatsit, (b) (very important) ease of adjustment of the water level height after installation, and (c) perhaps a model that undoes from inside for super-easy future replacement and repair.

I read one reviewer who said he needed to remove his chosen valve for adjustment - either he's mistaken, or the designer of that valve should be thoroughly chastened with a nailed plank.

lucyplease

Thank you, I did sneak an extra picture in there ! 

I have a photo from the side - but I can’t see a make on it. 

I should have said earlier that sometimes it flows quite heavily into the pan. - like a water feature :-/ would that still be the valve? So odd it’s mainly when we turn  another tap on! 

I have been having a proper look just now (fun!) and after flushing it seems to fill until the little inside blue thing rises (no idea what this is called) then about 5 mins (or if we turn tap on) later starts to fill again in the cistern and then into the pan. 

Thanks we do have a screw fix near!

Jeepers_Creepers

These are clever little valves.

Original inlet valves had a sealed floating ball on an  arm which rose with the water level - yer literal 'ballcock'. As the arm rose, it would steadily move to shut off the inlet orifice (matron!), and this meant that it was a longer drawn-out process with the flow reducing to a trickle, then drips and finally offski.

These new valves work in a way I once understood but have since forgotten, and my life isn't quite dull enough to read about it again. Essentially, tho', it employs the water pressure to help shut off the flow; once the level hits a set point, a mechanism inside the valve 'trips' and uses this pressure to quickly shut off the flow. Ie, it doesn't slowly fall to a trickle and then off, but it fills full-on and then shuts off in an 'instant' (relatively speaking).

The funny blue thing is the 'float'. Again, that's a clever design because the 'old' balls sometimes leaked and water got inside them, so they stopped working. How to fix this? I know - remove the bottom of the 'ball' so it's like an upturned cup. Now it empties every time the water level drops, so it cannot be affected by 'leaks'. (Nods approvingly...)

Scale and wear builds up on the delicate shut-off mech, tho', and this will stop it working properly. Quite possibly you could disassemble it, clean it all up, give it a smear of silicone grease and reassemble it, but - frankly - it ain't wurf the bovver.

Choose a replacement - say the Fluidmaster with brass spigot - and swap it. You CAN do this :-) 

(What 'system' do you have - combi or vented?)

Homer_home

Buy this
https://www.screwfix.com/p/fluidmaster-bottom-entry-fill-valve-/84007?tc=GC8&ds_kid=92700055281954514&ds_rl=1249404&gclid=EAIaIQobChMIq6nptIKA7gIVjrrtCh3bFQt0EAQYAiABEgJlkPD_BwE&gclsrc=aw.ds


Turn water off, place towel under flexible hose, flush toilet, remove rest of water in cistern using a rag, undo  flexible hose (towel placed to catch drips, undo inlet valve (big plastic nut underneath of cistern, hold inlet valve whilst you do) , remove old inlet valve and clean cistern where it sits, reverse process to fit new one do not overtighten flexible hose hand tight then a quarter turn will do too tight and you will cut through the rubber washer

Don't forget to read instructions on how to adjust the height to suit your cistern 

Homer_home

Only valve I don't recommend is a torbeck valve , every one I have either fitted or had a look at has failed within a short period 

Jeepers_Creepers

As he says^

Homer, why not the brass spigotted version? Less likely to cross-thread (man, the number of times that's happened to me...)

And Lucy, familiarise yourself with how to adjust the water level height before fitting the valve - have a play with it before even starting.

Homer_home

Jeepers_Creepers said:

As he says^

Homer, why not the brass spigotted version? Less likely to cross-thread (man, the number of times that's happened to me...)

And Lucy, familiarise yourself with how to adjust the water level height before fitting the valve - have a play with it before even starting.

Good point , brass is better, linked to the wrong one , now edited